# Patent

## Title
Systems and methods for effectively interacting with a flash memory

## Abstract

Various systems and methods to use a plurality of linked lists for keeping track of changes to be made in data sets currently in a flash memory. To enhance efficiency of the system, the changes to be made in any particular data set are aggregated in a random access memory (“RAM”) until a sufficient volume of changes have been aggregated to justify a rewrite of the flash memory block in which the particular data set is stored. Since a flash memory may have millions of memory blocks and data sets, there are potentially tremendous demands on the memory resources of the RAM to keep track of all the changes, but the problem presented by these potential demands is avoided through the use of linked lists, in which each list links all of the changes that have been aggregated in RAM and that apply to one specific data set.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 61/982,381, filed on Apr. 22, 2014, which is hereby incorporated by reference.
The present application is also related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 62/089,453, filed on Dec. 9, 2014, which is hereby incorporated by reference.
The present application is also related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 62/109,663, filed on Jan. 30, 2015, which is hereby incorporated by reference.
The present application is also related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 62/121,523, filed on Feb. 27, 2015, which is hereby incorporated by reference.
The present application is also related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 62/129,876, filed on Mar. 8, 2015, which is hereby incorporated by reference.
The present application is also related to and claims priority under 35 USC §120 to U.S. Provisional Application No. 62/141,904, filed on Apr. 2, 2015, which is hereby incorporated by reference.
The following U.S. Patent Applications may include related subject matter to the following U.S. Patents: U.S. patent application Ser. No. 14/641,401, filed Mar. 8, 2015, now U.S. Pat. No. 9,547,553; U.S. patent application Ser. No. 14/740,793, filed Jun. 16, 2015, now U.S. Pat. No. 9,594,696; U.S. patent application Ser. No. 14/740,885, filed Jun. 16, 2015, now U.S. Pat. No. 9,529,622; U.S. patent application Ser. No. 14/806,835, filed Jul. 23, 2015, now U.S. Pat. No. 9,477,412; and U.S. patent application Ser. No. 14/806,861, filed Jul. 23, 2015, now U.S. Pat. No. 9,594,688.


BACKGROUND
Flash memory is stored in blocks. When a change must be made to the data in a block, no matter how minor the change may be, the entire block must be rewritten. On the one hand, the rewriting of flash memory blocks every time a single change must be made both consumes significant time and also places great demands on system resources. On the other hand, to buffer minor changes for each of the blocks in a dedicated RAM memory space and thus rewrite blocks only when a significant number of changes have been accumulated, would require enormous processing and memory resources that are simply not available in operating systems, especially when a very large number of blocks are affected by a very large number of minor changes over a short period. Systems and methods that would help resolve this conflict could potentially have a major beneficial influence on the performance of a data processing system that includes flash memory.
SUMMARY
Described herein are systems and methods to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory within a data processing system. In one particular form of such embodiment, the system (790 in FIG. 26) includes a first compute element, and a first flash memory comprising a plurality of blocks currently storing a plurality of data sets. The system further includes a first random access memory comprising a plurality of linked lists associated with the plurality of blocks, in which each linked list records a respective plurality of requirements to change the data set of the respective block, in which the plurality of requirements were made by the first compute element and have been accumulated in the linked list since the data set was last written to the respective block. Further, the system is configured to identify one of the linked lists as being currently in condition to be used for updating the respective block, to traverse the linked list identified in order to accumulate all the respective plurality of requirements into an aggregated requirement to change the data set of the respective block, and change the data set of the respective block by performing a flash block write to the respective block in conjunction with the aggregated requirement.
One embodiment is a system (790 in FIG. 26) operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory. In one particular form of such embodiment, the system includes a first compute element and a first flash memory comprising a plurality of blocks currently storing respectively a plurality of data sets. The system further includes a first random access memory comprising a plurality of linked lists associated respectively with the plurality of blocks, in which each linked list records a respective plurality of requirements to change the data set of the respective block, and in which the plurality of requirements were made by the first compute element and have been accumulated in the linked list since the data set was last written to the respective block. Further, the first compute element is configured to make a new requirement to change the data set of one of the blocks. Further, the system is configured to link the new requirement to the linked list associated with the one of the blocks, thereby appending the new requirement to the plurality of requirements already associated with the one of the blocks.
One embodiment is a system (790 in FIG. 26) operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory. In one particular form of such embodiment, the system includes a first compute element, and a first flash memory comprising a plurality of blocks currently storing respectively a plurality of data sets. The system further includes a first random access memory comprising a plurality of linked lists associated respectively with the plurality of blocks in which each linked list records a respective plurality of requirements to change the data of the respective block, and in which the plurality of requirements were made by the first compute element and have been accumulated in the linked list since the data set was last written to the respective block. Further, the system is configured to receive a first request to read a first data associated with the data set stored in one of the blocks, read the data set from the one of the blocks, traverse the linked list associated with the one of the blocks in order to accumulate all the respective plurality of requirements into an aggregated requirement to change the data set of the one of the blocks, update the data set read using said aggregated requirement into an updated data set, and respond to the first request by extracting the first data from the updated data set.
One embodiment is a method (FIG. 27) for using a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory. In one particular form of such embodiment, a first random access memory records a plurality of linked lists associated respectively with a plurality of blocks of a first flash memory, in which each linked list is a record of a respective plurality of requirements to change a data set associated with the respective block. Further, the first compute element identifies one of the linked lists as being currently in condition to be used for updating the respective block. Further, the first compute element traverses the linked list identified in order to accumulate all the respective plurality of requirements into an aggregated requirement to change the data set of the respective block. Further, a second compute element changes the data set of the respective block by performing a flash block write to the respective block in conjunction with the aggregated requirement.



BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments are herein described, by way of example only, with reference to the accompanying drawings. No attempt is made to show structural details of the embodiments in more detail than is necessary for a fundamental understanding of the embodiments. In the drawings:
FIG. 1A illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium;
FIG. 1B illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet;
FIG. 1C illustrates one embodiment of a system configured to implement a cache related memory transaction over a shared input-output medium;
FIG. 1D illustrates one embodiment of a system configured to implement a general communication transaction over a shared input-output medium;
FIG. 2A illustrates one embodiment of a system configured to transmit data packets associated with both either a cache related memory transaction or a general communication transactions;
FIG. 2B illustrates one embodiment of a system designed to temporarily stop and then resume the communication of data packets for general communication transactions;
FIG. 3A illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is a PCIE computer expansion bus, and the medium controller is a root complex;
FIG. 3B illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is an Ethernet connection, and the medium controller is a MAC layer;
FIG. 3C illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is an InfiniBand interconnect;
FIG. 4 illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which the system is implemented in a single microchip. In some embodiments, the various elements presented in FIG. 4 may be implemented in two or more microchips;
FIG. 5A illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which there is a fiber optic line and electrical/optical interfaces;
FIG. 5B illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which there are two or more fiber optic lines, and in which each fiber optic line has two or more electrical/optical interfaces;
FIG. 6A illustrates one embodiment of a method for stopping transmission of a data packet associated with a general communication transaction, and starting transmission of a data packet associated with a cache agent;
FIG. 6B illustrates one embodiment of a method for delaying transmission of a data packet associated with a general communication transaction, and transmitting instead a data packet associated with a cache agent;
FIG. 7A illustrates one embodiment of a system configured to cache automatically an external memory element as a result of a random-access read cycle;
FIG. 7B illustrates one embodiment of prolonged synchronous random-access read cycle;
FIG. 7C illustrates one embodiment of a system with a random access memory that is fetching at least one data element from an external memory element, serving it to a compute element, and writing it to the random access memory;
FIG. 7D illustrates one embodiment of a DIMM system configured to implement communication between an external memory element, a first RAM, and a first computer element;
FIG. 7E illustrates one embodiment of a system controller configured to fetch additional data elements from additional memory locations of an external memory, and write such data elements to RAM memory;
FIG. 7F illustrates one embodiment of a process by which a system the writing of additional data elements to RAM memory occurs essentially concurrently with additional synchronous random-access write cycles;
FIG. 8A illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules;
FIG. 8B illustrates one embodiment of system configured to fetch sets of data from a shared memory pool;
FIG. 8C illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a first compute element is placed on a first motherboard, a first DIMM module is connected to the first motherboard via a first DIMM slot, and first data link is comprised of a first optical fiber;
FIG. 8D illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a second compute element is placed on a second motherboard, a second DIMM module is connected to the second motherboard via a second DIMM slot, and a second data link is comprised of a second optical fiber;
FIG. 8E illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which each of the memory modules and the shared memory pool resides in a different server;
FIG. 8F illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a first memory module includes a first RAM operative to cache sets of data, a first interface is configured to communicate with a first compute element, and a second interface is configured to transact with the shared memory pool;
FIG. 8G illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which sets of data are arranged in a page format;
FIG. 8H illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, wherein a memory module includes a first RAM comprising a first bank of RAM and a second bank of RAM;
FIG. 8I illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, wherein a memory module includes a first RAM comprising a first bank of RAM and a second bank of RAM;
FIG. 9 illustrates one embodiment of a system configured to propagate data among a plurality of computer elements via a shared memory pool;
FIG. 10A illustrates one embodiment of a system configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network;
FIG. 10B illustrates one embodiment of a system configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network;
FIG. 10C illustrates one embodiment of a system configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network and a plurality of optical fiber data interfaces;
FIG. 10D illustrates one embodiment of a system configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network, and a second plurality of servers housing a second plurality of memory modules;
FIG. 11A illustrates one embodiment of a system configured to use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys;
FIG. 11B illustrates one embodiment of a system configured to request and receive data values needed for data processing;
FIG. 11C illustrates one embodiment of a system configured to streamline a process of retrieving a plurality of values from a plurality of servers using a plurality of keys;
FIG. 11D illustrates one embodiment of a system configured to minimize or at least reduce the duration of time periods between general tasks executed by a first compute element;
FIG. 11E illustrates one embodiment of a system configured to increase the utilization rate of a first compute element;
FIG. 11F illustrates one embodiment of a system configured to achieve a relatively high computational duty-cycle by at least temporarily blocking or redirecting the execution of certain processes;
FIG. 12 illustrates one embodiment of a method for mixing and timing, relatively efficiently, at least two key-value transactions in conjunction with a distributed key-value-store (KVS);
FIG. 13A illustrates one embodiment of a system configured to interleave high priority key-value transactions together with lower priority transactions over a shared input-output medium;
FIG. 13B illustrates one embodiment of a system configured to interleave high priority key-value transactions together with lower priority transactions over a shared input-output medium, in which both types of transactions are packet-based transactions;
FIG. 13C illustrates one embodiment of part of a system configured to interleave high priority key-value transactions together with lower priority transactions over a shared input-output medium, comprising a network-interface-card (NIC) including a medium-access-controller (MAC);
FIG. 14A illustrates one embodiment of a method for mixing high priority key-value transaction together with lower priority transactions over a shared input-output medium without adversely affecting performance;
FIG. 14B illustrates one embodiment of a method for mixing high priority key-value transactions together with lower priority transactions over a shared input-output medium without adversely affecting performance;
FIG. 14C illustrates one embodiment of a method for reducing latency associated with a key-value transaction involving a distributed data store interconnected by a network;
FIG. 15A illustrates one embodiment of a system operative to control random memory access in a shared memory pool;
FIG. 15B illustrates one embodiment of a sub-system with an access controller that includes a secured configuration which may be updated by a reliable source;
FIG. 15C illustrates one alternative embodiment of a system operative to control random memory access in a shared memory pool;
FIG. 16A illustrates one embodiment of a method for determining authorization to retrieve a value in a key-value store while preserving low latency associated with random-access retrieval;
FIG. 16B illustrates one alternative embodiment of a method for determining authorization to retrieve a value in a key-value store while preserving low latency associated with random-access retrieval;
FIG. 17A illustrates one embodiment of a system operative to distributively process a plurality of data sets stored on a plurality of memory modules;
FIG. 17B illustrates one embodiment of a system in which a plurality of compute elements send data requests to a single data interface;
FIG. 17C illustrates one embodiment of a system in which the data interface then accesses multiple data sets stored in a single memory module, and then sends each such data set to the correct compute element;
FIG. 17D illustrates one embodiment of a system in which a single compute element sends a plurality of data requests to a plurality of data interfaces;
FIG. 17E illustrates one embodiment of a system in which a single compute element receives responses to data requests that the compute element sent to a plurality of data interfaces, in which each data interface fetches a response from an associated memory module and sends that response to the compute element;
FIG. 18 illustrates one embodiment of a method for storing and sending data sets in conjunction with a plurality of memory modules;
FIG. 19A illustrates one embodiment of a system operative to achieve load balancing among a plurality of compute elements accessing a shared memory pool;
FIG. 19B illustrates one embodiment of a system including multiple compute elements and a first data interface, in which the system is operative achieve load balancing by serving data sets to the compute elements proportional to the rate at which the compute elements request data sets for processing;
FIG. 20 illustrates one embodiment of a method for load balancing a plurality of compute elements accessing a shared memory pool;
FIG. 21A illustrates one embodiment of a system operative to achieve data resiliency in a shared memory pool;
FIG. 21B illustrates one embodiment of a sub-system with a compute element making a data request to an erasure-encoding interface which converts the request to a plurality of secondary data requests and sends such secondary data requests to a plurality of data interfaces;
FIG. 21C illustrates one embodiment of a sub-system with the plurality of data interfaces using random-access read cycles to extract data fragments stored in associated memory modules;
FIG. 21D illustrates one embodiment of a sub-system with the plurality of data interfaces sending, as responses to the secondary data requests, data fragments to the erasure-coding interface which reconstructs the original data set from the data fragments and sends such reconstructed data set to the compute element as a response to that compute element's request for data;
FIG. 21E illustrates one embodiment of a sub-system with a compute element streaming a data set to an erasure-coding interface which converts the data set into data fragments and streams such data fragments to multiple data interfaces, which then write each data fragment in real-time in the memory modules associated with the data interfaces;
FIG. 22A illustrates one embodiment of a system operative to communicate, via a memory network, between compute elements and external destinations;
FIG. 22B illustrates one embodiment of a system operative to communicate, via a switching network, between compute elements and memory modules storing data sets;
FIG. 23A illustrates one embodiment of a method for facilitating general communication via a switching network currently transporting a plurality of data elements associated with a plurality of memory transactions;
FIG. 23B illustrates an alternative embodiment of a method for facilitating general communication via a switching network currently transporting a plurality of data elements associated with a plurality of memory transactions;
FIG. 24A illustrates one embodiment of a system configured to generate automatically a procedure to effectively combine fetching and processing of data sets;
FIG. 24B illustrates one embodiment of a compute element operative to fetch and process data sets, including a depiction of the requests for data sets and the reception of data sets;
FIG. 24C illustrates one embodiment of a system configured to generate automatically a procedure to effectively combine fetching and processing of data sets, in which executable instructions are executed immediately upon their receipt by an executing compute element;
FIG. 25 illustrates one embodiment of a method for generating a sequence of executable instructions operative to combine effectively fetching and processing of data sets;
FIG. 26 illustrates one embodiment of a system using a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory; and
FIG. 27 illustrates one embodiment of a method for keeping track of changes to be made in data sets currently stored in a flash memory.



DETAILED DESCRIPTION
In this description, “cache related memory transaction” or a “direct cache related memory transaction” is a transfer of one or more data packets to or from a cache memory. A “latency-critical cache transaction” is a cache transaction in which delay of a data packet to or from the cache memory is likely to delay execution of the task being implemented by the system.
In this description, “general communication transaction” is a transfer of one or more data packets from one part of a communication system to another part, where neither part is a cache memory.
In this description, a “communication transaction” is a transfer of one or more data packets from one part of a communication system to another part. This term includes both “cache related memory transaction” and “general communication transaction”.
In this description, a “shared input-output medium” is part of a system that receives or sends both a data packet in a cache related memory transaction and a data packet in a general communication transaction. Non-limiting examples of “shared input-output medium” include a PCIE computer extension bus, an Ethernet connection, and an InfiniBand interconnect.
In this description, an “external I/O element” is a structural element outside of the system. Non-limiting examples include a hard disc, a graphic card, and a network adapter.
In this description, an “external memory element” is a structure outside the system that holds data which may be accessed by the system in order to complete a cache related memory transaction or other memory transactions.
In this description, “cache-coherency” is the outcome of a process by which consistency is achieved between a cache memory and one or more additional cache memory locations inside or external to the system. Generally, data will be copied from one source to the other, such that coherency is achieved and maintained. There may be a separate protocol, called a “cache-coherency protocol”, in order to implement cache-coherency.
In this description, an “electro-optical interface” is a structure that allows conversion of an electrical signal into an optical signal, or vice versa.
In this description, a “prolonged synchronous random-access read cycle” is a synchronous RAM read cycle that has been lengthened in time to permit access from an external memory element.
In this description, “shared memory pool” is a plurality of memory modules that are accessible to at least two separate data consumers in order to facilitate memory disaggregation in a system.
In this description, “simultaneously” means “essentially simultaneously”. In other words, two or more operations occur within a single time period. This does not mean necessarily that each operation consumes the same amount of time—that is one possibility, but in other embodiments simultaneously occurring operations consume different amounts of time. This also does not mean necessarily that the two operations are occurring continuously—that is one possibility, but in other embodiments an operation may occur in discrete steps within the single time period. In this description, “simultaneity” is the action of two or more operations occurring “simultaneously”.
In this description, “efficiently” is a characterization of an operation whose intention and/or effect is to increase the utilization rate of one or more structural elements of a system. Hence, “to efficiently use a compute element” is an operation that is structured and timed such that the utilization rate of the compute element is increased. Hence, “efficiently mixing and timing at least two key-value transactions” is an operation by which two or more needed data values are identified, requested, received, and processed, in such a manner that the utilization rate of the compute element in increased.
In this description, “utilization rate” is the percentage of time that a structural element of a system is engaged in useful activity. The opposite of “utilization rate” is “idle rate”.
In this description, a “needed data value” is a data element that is held by a server and needed by a compute element to complete a compute operation being conducted by the compute element. The phrase “data value” and the word “value” are the same as “needed data value”, since it is understand that in all cases a “value” is a “data value” and in all cases a “data value” is needed by a compute element for the purpose just described.
In this description, “derive” is the operation by which a compute element determines that a needed data value is held by one or more specific servers. The phrase “derive” sometimes appears as “identify”, since the objective and end of this operation is to identify the specific server or servers holding the needed data value. If a needed data value is held in two or more servers, in some embodiments the compute element will identify the specific server that will be asked to send the needed data value.
In this description, “request” is the operation by which a compute element asks to receive a needed set of data or data value from a server holding that set of data or data value. The request may be sent from the compute element to either a NIC and then to a switched network or directly to the switched network. The request is then sent from the switched network to the server holding the needed data value. The request may be sent over a data bus.
In this description, “propagation of a request” for a needed data value is the period of time that passes from the moment a compute element first sends a request to the moment that that the request is received by a server holding the needed data value.
In this description, “get” is the operation by which a compute element receives a needed data value from a server. The needed data value is sent from the server to a switching network, optionally to a NIC and then optionally to a DMA controller or directly to the DMA controller, and from the DMA controller or the NIC or the switching network either directly to the compute element or to a cache memory from which the compute element will receive the needed data value.
In this description, “process” is the operation by which a compute element performs computations on a needed data value that it has received. In other words, the compute element fulfills the need by performing computations on the needed data element. If, for example, the social security number of a person is required, the “needed data value” may be the person's name and number, and the “process” may by the operation by which the compute element strips off the number and then applies it in another computation or operation.
In this description, “compute element” is that part of the system which performs traditional computational operations. In this description, it may be the part of the system that performs the derive, request, and process operations. In some embodiments, the compute element also receives the needed data value from a server, via a switching network, a DMA, and optionally a NIC. In other embodiments, the requested data value is not received directly by the compute element, but is received rather by the cache memory, in which case the compute element obtains the needed value from the cache memory. A compute element may or may not be part of a CPU that includes multiple compute elements.
In this description, “executing the request” is the operation during which a server that has received a request for a needed data value identifies the location of the needed data value and prepares to send the needed data value to a switching network.
In this description, “key-value transaction” is the set of all the operations in which a location of a needed data value is “derived” from a key, the data value is “requested” optionally with the key sent by a compute element through a communication network to a server holding the data value, the request received by the server, “executed” by the server, the data value sent by the server through the communication network, “gotten” by the compute element, and “processed” by the compute element.
In this description, “latency-critical” means that a delay of processing a certain request for a value may cause a delay in system operation, thereby introducing an inefficiency into the system and degrading system performance. In some embodiments, the period of time for a “latency-critical” operation is predefined, which means that exceeding that predefined time will or at least may degrade system performance, whereas completing the operation within that period of time will not degrade system performance. In other embodiments, the time period that is “latency-critical” is predefined, but is also flexible depending on circumstances at the particular moment of performing the latency-critical operation.
In this description, “determining” whether a compute element is authorized to access a particular data set in a shared memory pool is the process that determines whether a particular compute element in a system has been authorized by some reliable source to access a particular data set that is stored in a shared memory pool.
In this description, “accessing” a data set encompasses any or all of entering an original value in a data set, requesting to receive an existing data set, receiving an existing data set, and modifying one or more values in an existing data set.
In this description, “preventing” delivery of a data set to a compute element is the process by which an access controller or other part of a system prevents such data set from being delivered to the compute element, even though specifically requested by the compute element. In some cases, denial of access is total, such that the compute element may not access any part of the data set. In some cases, denial access is partial, such that the compute element may access part but not all of a data set. In some cases, denial is conditional, such that the compute element may not access the data set in its current form, but the system may modify the data set such that the compute element may access the modified data set. The prevention of delivery may be achieved using various techniques, such as blocking of communication, interfering with electronic processes, interfering with software processes, altering addresses, altering data, or any other way resulting in such prevention.
In this description, “data set” is a data structure that a compute element might access in order for the compute element to process a certain function. A data set may be a single data item, or may be multiple data items of any number or length.
In this description, a “server” may be a computer of any kind, a motherboard (MB), or any other holder of structures for either or both of data memory and data processing.
In this description, “random access memory” may include RAM, DRAM, flash memory, or any other type of memory element that allows random access to the memory element, or at least a random access read cycle in conjunction with the memory element. The term does not include any type of storage element that must be accessed sequentially, such as a sequentially-accessed hard disk drive (HDD) or a sequentially accessed optical disc.
In this description, “data interface” is a unit or sub-system that controls the flow of data between two or more parts of a system. A data interface may alter the data flowing through it. A data interface may handle communication aspects related to the flow of data, such as networking. A data interface may access memory modules storing the data. A data interface may handle messages in conjunction with the two or more parts of the system. A data interface may handle signaling aspects related to controlling any of the parts of the system. Some possible non-limiting examples of a “data interface” include an ASIC, an FPGA, a CPU, a microcontroller, a communication controller, a memory buffer, glue logic, and combinations thereof.
In this description, “data corpus” is the entire amount of data included in related data sets, which together make up a complete file or other complete unit of information that may be accessed and processed by multiple compute elements. As one example, the data corpus may be a copy of all the pages in the Internet, and each data set would be a single page.
In this description, a “memory module” is a physical entity in a system that stores data and that may be accessed independently of any other memory module in the system and in parallel to any other memory module in the system. Possible examples include a DIMM card or other physical entity that may be attached or removed from the system, or a memory chip that is part of the system but that is not necessarily removed or re-attached at will.
In this description, “data resiliency” means the ability of a system to reconstruct a data set, even if the system does not have all of the data that makes up that data set. Any number of problems may arise in that require “data resiliency”, including, without limitation, (i) the destruction of data, (ii) the corruption of data, (iii) the destruction of any part of the operating, application, or other software in the system, (iv) the corruption of any part of operating, application, or other software in the system, (v) the destruction of a compute element, erasure-coding interface, data interface, memory module, server, or other physical element of the system, and (vi) the malfunction, whether temporary or permanent, of a compute element, erasure-coding interface, data interface, memory module, server, or other physical element of the system. In all such cases, the system is designed and functions to provide “data resiliency” to overcome the problem, and thus provide correct and whole data sets.
In this description, an “external destination” is a destination that is outside a system, wherein such system may include a switching network, compute elements, and memory modules storing data sets. An external destination may be a data center, a computer, a server, or any other component or group of components that are capable of receiving an electronic communication message.
In this description, a “respective block” means the specific memory block within a flash memory that is associated with a particular linked list, such that aggregation of all the changes indicated in the linked list will result in execution of all such changes when the memory block is rewritten.
FIG. 1A illustrates one embodiment of a system 100 configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium 105. The system 100 includes a number of computing elements, including a first compute element 100-c1 through N-th compute element 100-cn. The compute elements are in communicative contact with a cache memory 101, which is in communicative contact with a cache agent 101-ca that controls communication between the cache memory 101 and a medium controller 105-mc. The medium controller 105-mc controls communication between the cache agent 101-ca and a shared input-output medium 105, which is communicative contact with an external memory elements 112 that is outside the system 100.
FIG. 1B illustrates one embodiment of a system 100 configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium 105, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet. Here two transactions are illustrated. One transaction 101-tran is a cache related memory transaction between the cache memory 101 and the external memory element 112, via the cache agent 101-ca, the medium controller 105-mc, and the shared input-output medium 105. Transaction 101-tran can go to the cache memory 101, or to the external memory element 112, or in both directions, and may include a cache-coherency transaction. In some embodiments, there is an additional path 101-init between the cache agent 101-ca and the cache memory 101, in which the cache agent initiates transaction 101-tran. The second transaction 106-tran, is a general communication transaction between a part of the system other than the cache memory 101, and some external element other than the external memory element 112, such as an external I/O elements 119 in FIG. 1D. This transaction 106-tran also goes through the shared input-output medium 105 and the medium controller 105-mc, but then continues to another part of the system rather than to the cache agent 101-ca. 
FIG. 1C illustrates one embodiment of a system configured to implement a cache related memory transaction over a shared input-output medium 105. The DMA controller 105-dma performs copy operations 101-copy from the cache memory 101 into the media controller 105-mc, and from the media controller to the external memory element 112, or vice-versa.
FIG. 1D illustrates one embodiment of a system configured to implement a general communication transaction over a shared input-output medium 105. The DMA controller 105-dma performs copy operations 106-copy from a non-cache related source (not shown) into the media controller 105-mc, and from the media controller to the external I/O element 119, or vice-versa.
FIG. 2A illustrates one embodiment of a system configured to transmit data packets associated with both either a cache related memory transaction or a general communication transactions. It illustrates that transactions occur in the form of data packets. The cache related memory transaction 101-tran includes a number of data packets, P1, P2, through Pn, that will pass through the medium controller 105-mc. Again, the data packets may flow in either or both ways, since data packets may transmit to or from the cache memory. The cache related memory transaction 101-tran is a packetized transaction 101-tran-P. In the same, or at least an overlapping time period, there is a general communication transaction 106-tran which includes a number of data packets P1, P2, through Pn, which are all part of the general communication transaction 106-tran that is a packetized transaction 106-tran-P. This packetized transaction 106-tran-P also passes through the medium controller 105-mc, and may pass in both directions.
FIG. 2B illustrates one embodiment of a system designed to temporarily stop and then resume the communication of data packets for general communication transactions. Here, a general packetized communication transaction 106-tran-P includes a first packet 106-tran-first-P. After transaction 106-tran-P has begun, but while first packet 106-tran-first-P is still in process, a packetized cache related memory transaction 101-tran-P begins with a second packet 101-trans-second-P. When the system understands that there are two transactions occurring at the same time, one of which is cache related memory 101-tran-P and the other 106-tran-P not, the system will cause the general communication transaction to stop 106-stop transmission of the particular data packet 106-tran-first-P. After all of the data packets of 101-tran-P have passed the system, the system will then allow the general communication transaction to resume 106-resume and complete the transmission of packet 106-tran-first-P. In some embodiments, the system will allow completion of a data packet from 106-tran-P when such packet is in mid-transmission, but in some embodiments the system will stop the data packet flow of 106-tran-P even in mid-packet, and will then repeat that packet when the transaction is resumed 106-resume. In some of the various embodiments, the particular element that understands there are two transactions at the same time, and that stops and then resumes 106-tran-P, is the medium controller element 105-mc or some other controller such as those illustrated and explained in FIGS. 3A, 3B, and 3C, below.
FIG. 3A illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is a PCIE computer expansion bus 105-pcie, and the medium controller is a root complex 105-root. In FIG. 3A, the specific shared input-output medium 105 is a PCIE computer expansion bus 105-pcie, and the specific medium controller 105-mc is a root complex 105-root. Both the cache related memory transaction 101-tran and the general communication transaction 106-tran pass through both 105-pcie and 105-root. 
FIG. 3B illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is an Ethernet connection 105-eth, and the medium controller is a MAC layer 105-mac. In FIG. 3B, the specific shared input-output medium 105 is an Ethernet connection 105-eth, and the specific medium controller 105-mc is a MAC layer 105-mac. Both the cache related memory transaction 101-tran and the general communication transaction 106-tran pass through both 105-eth and 105-mac. 
FIG. 3C illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium, in which such shared input-output medium is an InfiniBand interconnect 105-inf. 
FIG. 4 illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium 105, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which the system is implemented in a single microchip. In some embodiments, the various elements presented in FIG. 4 may be implemented in two or more microchips. In FIG. 4, various elements of the system previously described are implemented in a single microchip 100-cpu. Such elements include various processing elements, 100c-1 through 100-cn, a cache memory 101, a cache agent 101-ca, a medium controller 105-mc, and a shared input-output medium 105. In FIG. 4, there is a cache related memory transaction 101-tran between cache memory 101 and an external memory element 112. There is further a general communication transaction 106-tran between an external I/O element 119, such as a hard disc, a graphic card, or a network adapter, and a structure other than the cache memory 101. In the particular embodiment illustrated in FIG. 4, the non-cache structure is a DRAM 110-dram, and the communication path between 110-dram and 119 includes a memory controller 110 as shown. The DRAM 110-dram may be part of a computer, and the entire microchip 100-cpu may itself be part of that computer. In other embodiments, the structure other than cache memory 101 may also be on chip 100-cpu but not cache memory 101, or the structure may be another component external to the chip 100-cpu other than DRAM 100-dram. 
FIG. 5A illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium 105, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which there is a fiber optic line 107-fiber-ab and electrical/optical interfaces 107-a and 107-b. In FIG. 5A, there is a cache related memory transaction 101-tran between cache memory 101 (not shown in FIG. 5A) and external memory element 112, in which data packets may move in both directions to and from the external I/O memory element 112, and electrical-optical interface 107b, a shared input-output medium 105 which as illustrated here is a fiber optic line 107-fiber-ab and another electrical-optical interface 107-a, and a medium controller 105-mc. The connection from 112 to 107-b is electrical, the electrical signal is converted to optical signal at 107-b, and the signal is then reconverted back to an electrical signal at 107-a. FIG. 5A includes also a general communication transaction 106-tran between an external I/O element 119 and either a part of the system that is either not the cache memory 101 (not shown in FIG. 5A) or that is outside of the system, such as 110-dram (not shown in FIG. 5A). The signal conversions for 106-tran are the same as for 101-tran. In the event that 101-tran and 106-tran occur simultaneously or at least with an overlap in time, the medium control 101-mc will either stop and resume, or at least delay, the 106-tran data packets to give priority to the 101-tran data packets.
FIG. 5B illustrates one embodiment of a system configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium 105, in which there is a conflict between a cache related memory I/O data packet and a general communication I/O data packet, and in which there are two or more fiber optic lines 107-fiber-cd and 107-fiber-ef, and in which each fiber optic line has two or more electrical/optical interfaces, 107-c and 107-d for 107-fiber-cd, and 107-e and 107-f for 107-fiber-ef. FIG. 5B presents one alternative structure to the structure shown in FIG. 5A. In FIG. 5B, the electrical-optical interfaces and the fiber optic line are not shared. Rather, cache related memory transaction 101-tran between external memory element 112 and cache memory 101 (not shown in FIG. 5B) occurs over e/o interface 107-d not shared with 106-tran, fiber optic line 107-fiber-cd not shared with 106-tran, e/o interface 107-c not shared with 106-tran, and medium controller 105-mc which is shared with 106-tran, and which senses multiple transactions and gives priority to 101-tran data packets. Also, general communication transaction 106-tran between external I/O element 119 and a non-cache element (not shown in FIG. 5B) occurs over e/o interface 107-f not shared with 101-tran, fiber optic line 107-fiber-ef not shared with 101-tran, e/o interface 107-e not shared with 101-tran, and medium controller 105-mc which is shared with 101-tran, senses multiple transactions, and give priority to 101-tran data packets.
One embodiment is a system 100 configured to mix cache related memory transactions together with general communication transactions over a shared input-output medium. Various embodiments include a shared input-output medium 105 associated with a medium controller 105-mc, a cache agent 101-ca, and a first cache memory 101 associated with said cache agent 101-ca. Further, in some embodiments, the cache agent 101-ca is configured to initiate 101-init direct cache related memory transactions 101-tran between the first cache memory 101 and an external memory element 112, via said shared input-output medium 105. Further, in some embodiments the medium controller 105-mc is configured to block general communication transactions 106-tran via said shared input-output medium 105 during the direct cache related memory transactions 101-tran, thereby achieving the mix of transactions without delaying the direct cache related memory transactions 101-tran. 
In one alternative embodiment to the system just described, the medium controller 105-mc includes a direct-memory-access (DMA) controller 105-dma configured to perform the direct cache related memory transactions 101-tran by executing a direct copy operation 101-copy between the first cache memory 101 and the external memory element 112 via the shared input-output medium 105.
In one possible variation of the alternative embodiment just described, the direct-memory-access (DMA) controller 105-dma is further configured to perform the general communication transactions 106-tran by executing another direct copy operation 106-copy in conjunction with an external input-output element 119 via the shared input-output medium 105.
In a second alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, further the direct cache related memory transactions 101-tran are latency-critical cache transactions. Further, the medium controller 105-mc is configured to interrupt any of the general communication transactions 106-tran and immediately commence the direct cache related memory transactions 101-tran, thereby facilitating the latency criticality.
In one possible variation of the second alternative embodiment just described, further both said direct cache related memory transactions 101-tran and general communication transactions 106-tran are packet-based transactions 101-tran-P, and 106-tran-P is performed via the medium controller 105-mc in conjunction with the shared input-output medium 105. Further, the medium controller 105-mc is configured to stop 106-stop on-going communication of a first packet 106-tran-first-P belonging to the general communication transactions 106-tran via the shared input-output medium 105, and substantially immediately commence communication of a second packet 101-tran-second-P belonging to the direct cache related memory transactions 101-tran via the shared input-output medium 105 instead, thereby achieving the interruption at the packet level.
In one possible configuration of the possible variation just described, further the medium controller 105-mc is configured to resume 106-resume communication of the first packet 106-tran-first-P after the second packet 101-tran-second-P has finished communicating, thereby facilitating packet fragmentation.
In a third alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, the shared input-output medium 105 is based on an interconnect element selected from a group consisting of (i) peripheral-component-interconnect-express (PCIE) computer expansion bus 105-pcie, (ii) Ethernet 105-eth, and (iii) InfiniBand 105-inf. 
In one embodiment associated with the PCIE computer expansion bus 105-pcie, the medium controller 105-mc may be implemented as part of a root-complex 105-root associated with said PCIE computer expansion bus 105-pcie. 
In one embodiment associated with the Ethernet 105-eth, the medium controller 105-mc may be implemented as part of a media-access-controller (MAC) 105-mac associated with said Ethernet 105-eth. 
In a fourth alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, further the direct cache related memory transactions 101-tran and general communication transactions 106-tran are packet-based transactions 101-tran-P, and 106-tran-P is performed via the medium controller 105-mc in conjunction with said the shared input-output medium 105. Further, the medium controller 105-mc is configured to deny access to the shared input-output medium 105 from a first packet 106-tran-first-P belonging to the general communication transactions 106-tran, and instead to grant access to the shared input-output medium 105 to a second packet 101-tran-second-P belonging to the direct cache related memory transactions 101-tran, thereby giving higher priority to the direct cache related memory transactions 101-tran over the general communication transactions 106-tran. 
In a fifth alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, further there is at least a first compute element 100-c1 associated with the cache memory 101, and there is a memory controller 110 associated with an external dynamic-random-access-memory (DRAM) 110-dram. Further, the system 100 is integrated inside a central-processing-unit (CPU) integrated-circuit 100-cpu, and at least some of the general communication transactions 106-tran are associated with the memory controller 110 and DRAM 110-dram. 
In a sixth alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, further the system achieves the mix without delaying the direct cache related memory transactions 101-tran, which allows the system 100 to execute cache-coherency protocols in conjunction with the cache memory 101 and the external memory element 112.
In a seventh alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, the shared input-output medium 105 includes an electro-optical interface 107-a and an optical fiber 107-fiber-ab operative to transport the direct cache related memory transactions 101-tran and the general communication transactions 106-tran. 
In an eighth alternative embodiment to the system of mixing cache related memory transactions together with general communication transactions, further including a first 107-c and a second 107-d electro-optical interface, both of which are associated with a first optical fiber 107-fiber-cd, and are operative to transport the direct cache related memory transactions 101-tran in conjunction with the medium controller 105 and the external memory element 112.
In a possible variation of the eighth alternative embodiment just described, further including a third 107-e and a fourth 107-f electro-optical interface, both of which are associated with a second optical fiber 107-fiber-ef, and are operative to transport the general communication transactions 106-tran in conjunction with the medium controller 105 and an external input-output element 119.
FIG. 6A illustrates one embodiment of a method for mixing cache related memory transactions 101-tran together with general communication transactions 106-tran over a shared input-output medium 105 without adversely affecting cache performance. In step 1011, a medium controller 105-mc detects, in a medium controller 105-mc associated with a shared input-output medium 105, an indication from a cache agent 101-ca associated with a cache memory 101, that a second packet 101-tran-second-P associated with a cache related memory transactions 101-tran is pending. In step 1012, as a result of the indication, the medium controller 105-mc stops transmission of a first packet 106-tran-first-P associated with a general communication transactions 106-tran via the shared input-output medium 105. In step 1013, the medium controller 105-mc commences transmission of the second packet 101-tran-second-P via said the input-output medium 105, thereby preserving cache performance in conjunction with the cache related memory transactions 101-tran. 
In a first alternative embodiment to the method just described, further the cache performance is associated with a performance parameter selected from a group consisting of: (i) latency, and (ii) bandwidth.
In a second alternative embodiment to the method just described for mixing cache related memory transactions together with general communication transactions over a shared input-output medium without adversely affecting cache performance, further the general communication transactions 106-tran are packet-based transactions 106-tran-P performed via the medium controller 105-mc in conjunction with the shared input-output medium 105. Also, the cache performance is associated with latency and this latency is lower than a time required to transmit a shortest packet belonging to said packet-based transaction 106-tran-P.
FIG. 6B illustrates one embodiment of a method for mixing cache related memory transactions together with general communication transactions over a shared input-output medium without adversely affecting cache performance. In step 1021, a medium controller 105-mc associated with a shared input-output medium 105 detects an indication from a cache agent 101-ca associated with a cache memory 101, that a second packet 101-tran-second-P associated with a cache related memory transactions 101-tran is pending. In step 1022, as a result of the indication, the medium controller 105-mc delays transmission of a first packet 106-tran-first-P associated with a general communication transaction 106-tran via the shared input-output medium 105. In step 1023, the medium controller 105-mc transmits instead the second packet 101-tran-second-P via the shared input-output medium 105, thereby preserving cache performance in conjunction with the cache related memory transactions 101-tran. 
In a first alternative embodiment to the method just described, the cache performance is associated with a performance parameter selected from a group consisting of: (i) latency, and (ii) bandwidth.
In a second alternative embodiment to the method just described for mixing cache related memory transactions together with general communication transactions over a shared input-output medium without adversely affecting cache performance, further the general communication transactions 106-tran are packet-based transactions 106-tran-P performed via the medium controller 105-mc in conjunction with the shared input-output medium 105. Also, the cache performance is associated with latency; and said latency is lower than a time required to transmit a shortest packet belonging to said packet-based transaction 106-tran-P.
FIG. 7A illustrates one embodiment of a system configured to cache automatically an external memory element as a result of a random-access read cycle. A system 200 is configured to cache automatically an external memory element as a result of a random-access read cycle. In one particular embodiment, the system includes a first random-access memory (RAM) 220-R1, a first interface 221-i1 configured to connect the system 200 with a compute element 200-c1 using synchronous random access transactions 221-tr, and a second interface 221-i2 configured to connect 221-connect the system 200 with an external memory 212.
FIG. 7B illustrates one embodiment of prolonged synchronous random-access read cycle. The system 200 is configured to prolong 221-tr-R-prolong a synchronous random-access read cycle 221-tr-R from the time period between T1 and T2 to the time period between T1 to T3, the prolongation being the period between T2 and T3.
FIG. 7C illustrates one embodiment of a system with a random access memory that is fetching at least one data element from an external memory element, serving it to a compute element, and writing it to the random access memory. In one particular embodiment, the prolong 221-tr-R-prolong (FIG. 7B) is initiated by the first computer element 200-c1 when the synchronous random-access read cycle 221-tr-R (FIG. 7B) is detected to be addressed to a first memory location 212-L1 of the external memory element 212 currently not cached by the first random-access memory 220-R1 (FIG. 7A). The system 200 is further configured to fetch 212-L1-fetch, via the second interface 221-i2 (FIG. 7A), from the external memory element 212, at least one data element 212-D1 associated with the first memory location 212-L1. The system is further configured to serve 212-D1-serve to the first compute element 200-c1, as part of the synchronous random-access read cycle 221-tr-R (FIG. 7B) prolonged, via the first interface 221-i1 (FIG. 7A), the at least one data element 212-D1 that was previously fetched, thereby concluding successfully the synchronous random-access read cycle 221-tr-R (FIG. 7B). The system is further configured to write 212-D1-write the at least one data element 212-D1 to the first random-access memory 220-R1, thereby caching automatically the first memory location 212-L1 for faster future access by the first compute element 200-c1.
FIG. 7D illustrates one embodiment of a DIMM system configured to implement communication between an external memory element, a first RAM, and a first computer element. In one particular embodiment, the first compute element 200-c1 is placed on a first motherboard 200-MB. Further, the system 200 is implemented on a first printed-circuit-board (PCB) having a form factor of a dual-in-line-memory-module (DIMM) 200-DIMM, such that the system 200 is connected to the first motherboard 200-MB like a dual-in-line-memory-module, and such that the first compute element 200-c1 perceives the system 200 as essentially a dual-in-line-memory-module. Further, the external memory element 212 is not placed on said first motherboard 200-MB. Further, the second interface 221-i2 (FIG. 7A) is an electrical-optical interface 221-i2-EO, connected to the external memory element 212 via an optical fiber 207-fiber, together operative to facilitate said connection 221-connect. In the embodiment shown in FIG. 7D, first RAM 220-R1 and first interface 221-i1 are structured and function as described in FIG. 7A.
FIG. 7E illustrates one embodiment of a system controller configured to fetch additional data elements from additional memory locations of an external memory, and write such data elements to RAM memory. The system 200 includes a system controller 200-cont that is configured to fetch 212-L1-fetch-add additional data elements 212-Dn respectively from additional memory locations 212-Ln of the external memory element 212, wherein the additional memory locations 212-Ln are estimated, based at least in part on the first memory location 212-L1 (FIG. 7C), to be accessed in the future by the compute element 200-c1 (FIG. 7A). The system controller 200-cont is further configured to write 212-Dn-write the additional data elements 212-Dn fetched to the first random-access memory 220-R1, thereby caching automatically the additional memory locations 212-Ln for faster future access by the first compute element 200-c1 (FIG. 7A).
FIG. 7F illustrates one embodiment of a process by which a system 200 (FIG. 7E) writing of additional data elements to RAM memory occurs concurrently with additional synchronous random-access write cycles. In FIG. 7E, the writing 212-Dn-write (FIG. 7E) of the additional data elements 212-Dn (FIG. 7E) is operated essentially concurrently with additional 221-tr-R-W-add synchronous random-access read cycles or synchronous random-access write cycles made by said first compute element 200-c1 (FIG. 7A) in conjunction with the first interface 221-i1 (FIG. 7A) and the first random-access memory 220-R1 (FIG. 7E).
FIG. 8A illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules. In one particular embodiment, the system 300 includes first 300-c1 and second 300-cn compute elements associated respectively with first 320-m1 and second 320-mn memory modules, each of said compute elements configured to communicate with its respective memory module using synchronous random access transactions 321-tr. The system includes further a shared memory pool 312 connected with the first and second memory modules via first 331-DL1 and second 331-DLn data links, respectively.
FIG. 8B illustrates one embodiment of system 300 (FIG. 8A) configured to fetch, by a first compute element, sets of data from a shared memory pool. FIG. 8B illustrates an additional embodiment of the system 300 (FIG. 8A) illustrated in FIG. 8A, wherein the system 300 is (FIG. 8A) configured to use the first 320-m1 and second 320-mn (FIG. 8A) memory modules as a cache to the shared memory pool 312, such that sets of data 312-D1 cached on the first 320-m1 or second 320-mn (FIG. 8A) memory modules are read 321-tr-R by the respective compute element 300-c1 or 300-cn (FIG. 8A) using the synchronous random access transactions 321-tr (FIG. 8A), and other sets of data 312-D2 that are not cached on said first or second memory module are fetched 331-DL1-fetch from the shared memory pool 312 into the first 320-m1 or second 320-mn (FIG. 8A) memory modules upon demand from the respective compute elements 300-c1 and 300-cn (FIG. 8A).
FIG. 8C illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a first compute element is placed on a first motherboard, a first DIMM module is connected to the first motherboard via a first DIMM slot, and first data link is comprised of a first optical fiber. In one particular embodiment of the system 300 (FIG. 8A), the first 320-m1 memory module is a first dual-in-line-memory-module (DIMM) 300-DIMM-1.
Further, the first compute element 300-c1 is placed on a first motherboard 300-MB-1, the first dual-in-line-memory-module 300-DIMM-1 is connected to the first motherboard 300-MB-1 via a first dual-in-line-memory-module slot 300-DIMM-1-slot, and the first data link 331-DL1 (FIG. 8A) includes a first optical fiber 307-fiber-1 with a connection to a shared memory pool 312.
FIG. 8D illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a second compute element is placed on a second motherboard, a second DIMM module is connected to the second motherboard via a second DIMM slot, and a second data link is comprised of a second optical fiber. FIG. 8D illustrates one particular embodiment of the system 300 (FIG. 8A) illustrated in FIG. 8C, in which further the second 320-mn memory module is a second dual-in-line-memory-module 300-DIMM-n, the second compute element 300-cn is placed on a second motherboard 300-MB-n, the second dual-in-line-memory-module 300-DIMM-n is connected to the second motherboard 300-MB-n via a second dual-in-line-memory-module slot 300-DIMM-n-slot, and the second data link 331-DLn (FIG. 8A) includes a second optical fiber 307-fiber-n connected to a shared memory pool 312.
FIG. 8E illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which each of the memory modules and the shared memory pool resides in a different server. FIG. 8E illustrates one particular embodiment of the system 300 (FIG. 8A) illustrated in FIG. 8D, in which further the first 300-MB-1 and second 300-MB-n motherboards are placed in a first 300-S-1 and a second 300-S-n server, respectively, and the shared memory pool 312 is placed in a third server 300-server, in which there is a first data link 331-DL1 between the first server 300-S1 and the third server 300-server and in which there is a second data link 331-DLn between the second server 300-S-n and the third server 300-server. The structure presented in FIG. 8E thereby facilitates distributed operation and memory disaggregation.
FIG. 8F illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which a first memory module includes a first RAM operative to cache sets of data, a first interface is configured to communicate with a first compute element, and a second interface is configured to transact with the shared memory pool. In the system 300 (FIG. 8A) the first memory module 320-m1 includes a first random-access memory 320-R1 configured to cache the sets of data 312-D1 (FIG. 8B), a first interface 321-i1 configured to communicate with the first compute element 300-c1 using the synchronous random access transactions 321-tr, and a second interface 321-i2 configured to transact with the external shared memory pool 312 via the first data link 331-DL1.
FIG. 8G illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, in which sets of data are arranged in a page format. In this system 300 (FIG. 8A), the sets of data 312-D1 (FIG. 8B) and other sets of data 312-D2 (FIG. 8B) are arranged in a page format 312-P1, 312-Pn respectively. Also, the system 300 (FIG. 8A) is further configured to conclude that at least some of said other sets of data 312-D2 (FIG. 8B) are currently not cached on the first memory module 320-m1, and consequently to issue, in said first compute element 300-c1, a page fault condition. The system 300 (FIG. 8A) consequently fetches 331-DL1-fetch at least one page 312-Pn from the shared memory pool 312, wherein the at least one page 312-Pn contains the at least some of the other sets of data 312-D2 (FIG. 8B). The system (FIG. 8A) further caches the at least one page 312-Pn in the first memory module 320-m1 for further use.
FIG. 8H illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, wherein a memory module includes a first RAM comprising a first bank of RAM and a second bank of RAM. FIG. 8H and FIG. 8I together illustrate one embodiment of a system 300 (FIG. 8A) that facilitates operation of the first random-access memory 320-R1 similar to a dual-ported random-access memory. In FIG. 8H, the first memory module 320-m1 includes a first random-access memory 320-R1 which itself includes first 320-D1 and second 320-D2 banks of dynamic-random-access-memory (DRAM). Concurrency is facilitated by the reading 321-tr-R (FIG. 8H) made from the first bank 320-D1 (FIG. 8H) by the first compute element while at the same time fetching 331-DL1-fetch (FIG. 8H) is done with the second bank 320-D2 (FIG. 8H).
FIG. 8I illustrates one embodiment of a system configured to cache a shared memory pool using at least two memory modules, wherein a memory module includes a first RAM comprising a first bank of RAM and a second bank of RAM. In FIG. 8I, the first memory module 320-m1 includes a first random-access memory 320-R1 which itself includes first 320-D1 and second 320-D2 banks of dynamic-random-access-memory (DRAM). Concurrency is facilitated by the reading 321-tr-R (FIG. 8I) made from the second bank 320-D2 (FIG. 8I) by the first compute element while at the same time fetching 331-DL1-fetch (FIG. 8I) is done with the first bank 320-D1 (FIG. 8I). The reading and fetching in FIG. 8I are implemented alternately with the reading and fetching in FIG. 8H, thereby facilitating operation of the first random-access memory 320-R1 as a dual-ported random-access memory.
FIG. 9 illustrates one embodiment of a system 400 configured to propagate data among a plurality of computer elements via a shared memory pool. In one particular embodiment, the system 400 includes a plurality of compute elements 400-c1, 400-cn associated respectively with a plurality of memory modules 420-m1, 420-mn, each compute element configured to exchange 409-ex1 data 412-D1 with the respective memory module using synchronous random access memory transactions 421-tr. The system 400 includes further a shared memory pool 412 connected with the plurality of memory modules 420-m1, 420-mn via a plurality of data links 431-DL1, 431-DLn respectively. In some embodiments, the system 400 is configured to use the plurality of data links 431-DL1, 431-DLn to further exchange 409-ex2 the data 412-D1 between the plurality of memory modules 420-m1, 420-mn and the shared memory pool 412, such that at least some of the data 412-D1 propagates from one 400-c1 of the plurality of compute elements to the shared memory pool 412, and from the shared memory pool 412 to another one 400-cn of the plurality of compute elements.
FIG. 10A illustrates one embodiment of a system 500 configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network 550. In one particular embodiment, the system 500 includes a first plurality of data interfaces 529-1, 529-2, 529-n configured to connect respectively to a plurality of compute elements 500-c1, 500-c2, 500-cn with the switching network 550. The system further includes a shared memory pool 512, which itself includes a plurality of memory modules 540-m1, 540-m2, 540-mn, connected to the switching network 550 via a second plurality of data interfaces 523-1, 523-2, 523-k, respectively.
FIG. 10B illustrates one embodiment of a system configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network. In one particular embodiment, the system 500 includes a switching network 550 operative to transport concurrently sets of data 512-D1, 512-D2, 512-Dn associated with a plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR. The system further includes a first plurality of data interfaces 529-1, 529-2, 529-n configured to connect respectively a plurality of compute elements 500-c1, 500-c2, 500-cn with the switching network 500. The system further includes a shared memory pool 512, which itself includes a plurality of memory modules 540-m1, 540-m2, 540-mk, connected to the switching network 550 via a second plurality of data interfaces 523-1, 523-2, 523-k respectively, where the shared memory pool 512 is configured to store or serve the sets of data 512-D1, 512-D2, 512-Dn concurrently by utilizing the plurality of memory modules concurrently, thereby facilitating a parallel memory access by the plurality of compute elements 500-c1, 500-c2, 500-cn in conjunction with the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR via the switching network 550.
FIG. 10C illustrates one embodiment of a system 500 configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network and a plurality of optical fiber data interfaces. In one particular embodiment, the system 500 includes a plurality of servers 500-S-1, 500-S-2, 500-S-n housing respectively said plurality of compute elements 500-c1 (FIG. 10B), 500-c2 (FIG. 10B), 500-cn (FIG. 10B), and a memory-server 500-S-memory housing said switching network 550 and a second plurality of data interfaces 523-1, 523-2, 523-k, which are connected to, respectively, memory modules 540-m1, 540-m2, and 540-mk. The system 500 further includes a first plurality of data interfaces 529-1 (FIG. 10B), 529-2 (FIG. 10B), 529-n (FIG. 10B), which themselves include, respectively, a plurality of optical fibers 507-fiber-1, 507-fiber-2, 507-fiber-n configured to transport a plurality of memory transactions 512-D1-TR (FIG. 10B), 512-D2-TR (FIG. 10B), 512-Dn-TR (FIG. 10B) between the plurality of servers 500-S-1, 500-S-2, 500-S-n and the memory-server 500-S-memory.
FIG. 10D illustrates one embodiment of a system 500 configured to allow a plurality of compute elements concurrent access to a shared memory pool, including one configuration of a switching network 550, and a second plurality of servers housing a second plurality of memory modules. In one particular embodiment, the system 500 includes a second plurality of servers 540-S-1, 540-S-2, 540-S-k housing respectively a plurality of memory modules 540-m1 (FIG. 10C), 540-m2 (FIG. 10C), 540-mk (FIG. 10C). In some particular embodiments, a second plurality of data interfaces 523-1 (FIG. 10C), 523-2 (FIG. 10C), 523-k (FIG. 10C) comprises respectively a plurality of optical fibers 517-fiber-1, 517-fiber-2, 517-fiber-k configured to transport a plurality of memory transactions 512-D1-TR (FIG. 10B), 512-D2-TR (FIG. 10B), 512-Dn-TR (FIG. 10B) between the second plurality of servers 540-S-1, 540-S-2, 540-S-k and the switching network 550.
One embodiment is a system 200 configured to cache automatically an external memory element 212 as a result of a random-access read cycle 221-tr-R. In one embodiment, the system includes a first random-access memory (RAM) 220-R1, a first interface 221-i1 configured to connect the system 200 with a first compute element 200-c1 using synchronous random access transactions 221-tr, and a second interface 221-i2 configured to connect 221-connect the system 200 with an external memory element 212. In some embodiments the system is configured to prolong 221-tr-prolong a synchronous random-access read cycle 221-tr-R initiated by the first compute element 200-c1 in conjunction with the first interface 221-i1 when the synchronous random-access read cycle 221-tr-R is detected to be addressed to a first memory location 221-L1 of the external memory element 212 currently not cached by the first random-access memory 220-R-1, fetch 212-L1-fetch via the second interface 221-i2 from the external memory element 212 at least one data element 212-D1 associated with the first memory location 212-L1, serve 212-D1-serve to the first compute element 200-c1 as part of said synchronous random-access read cycle 221-tr-R prolonged via the first interface 221-i1 the at least one data element 212-D1 that was previously fetched thereby concluding successfully said synchronous random-access read cycle 221-tr-R, and optionally write 212-D1-write the at least one data element 212-D1 to the first random-access memory 220-R1 thereby caching automatically the first memory location 212-L1 for faster future access by the first compute element 200-c1.
In one alternative embodiment to the system 200 just described to cache automatically an external memory element 212, further the first compute element is placed on a first motherboard 200-MB, the system 200 is implemented on a first printed-circuit-board (PCB) having a form factor of a dual-in-line-memory-module (DIMM) 200-DIMM such that the system 200 is connected to the first motherboard 200-MB like a dual-in-line-memory-module and such that said first compute element 200-c1 perceives the system 200 as essentially a dual-in-line-memory-module, the external memory element 212 is not placed on the first motherboard 200-MB, and the second interface 221-i2 is an electrical-optical interface 221-i2-EO connected to said external memory element 212 via an optical fiber 207-fiber together operative to facilitate the connection 221-connect. 
In a second alternative embodiment to the system 200 described above to cache automatically an external memory element 212, further the synchronous random-access read cycle 221-tr-R is performed using a signal configuration selected from a group consisting of (i) single-data-rate (SDR), (ii) double-data-rate (DDR), and (iii) quad-data-rate (QDR).
In a third alternative embodiment to the system 200 described above to cache automatically an external memory element 212, further the prolonging 221-tr-R-prolong of the synchronous random-access read cycle 221-tr-R is done in order to allow enough time for the system 200 to perform the fetch 212-L1-fetch, and further the synchronous random-access read cycle 221-tr-R is allowed to conclude at such time that said serving 212-D1-serve is possible, thereby ending said prolonging 221-tr-R-prolong.
In one possible variation of the third alternative embodiment just described, further the synchronous random-access read cycle 221-tr-R is performed over a double-data-rate (DDR) bus configuration, and the prolonging 221-tr-R-prolong is done using a procedure selected from a group consisting of: (i) manipulating a data strobe signal belonging to said DDR bus configuration, (ii) manipulating an error signal belonging to said DDR bus configuration, (iii) reducing dynamically a clock frame of the DDR bus configuration, (iv) adjusting dynamically a latency configuration associated with said DDR bus configuration, and (v) any general procedure operative to affect timing of said synchronous random-access read cycle 221-tr-R.
In a fourth alternative embodiment to the system 200 described above to cache automatically an external memory element 212, further a system controller 200-cont is included and configured to fetch 212-L1-fetch-add additional data elements 212-Dn respectively from additional memory locations 212-Ln of the external memory element 212 where the additional memory locations are estimated based at least in part on the first memory location 212-L1 and the memory locations are to be accessed in the future by said compute element 200-c1, and write 212-Dn-write the additional data elements 212-Dn fetched to the first random-access memory 220-R1 thereby caching automatically the additional memory locations 212-Ln for faster future access by the first compute element.
In one possible variation of the fourth alternative embodiment just described, further the writing 212-Dn-write of the additional data elements 212-Dn is operated concurrently with additional 221-tr-R-W-add synchronous random-access read cycles or synchronous random-access write cycles made by the first compute element 200-c1 in conjunction with the first interface 221-i1 and the first random-access memory 220-R1.
In one possible configuration of the possible variation just described, further the concurrent operation is made possible at least in part by the first random-access memory 220-R1 being a dual-ported random-access memory.
One embodiment is a system 300 configured to cache a shared memory pool 312 using at least two memory modules, including a first compute element 300-c1 and a second computer element 300-cn which are associated with, respectively, a first memory module 320-m1 and a second memory module 320-mn memory module, where each of the compute elements is configured to communicate with its respective memory module using synchronous random access transactions 321-tr. Also, a shared memory pool 312 connected with the first 320-m1 and second 320-mn memory modules via a first data link 331-DL1 and a second data link 331-DLn, respectively. In some embodiments, the system 300 is configured to use the first 320-m1 and second 320-mn memory modules as a cache to the shared memory pool 312, such that sets of data 312-D1 cached on the first 320-m1 or second 320-mn memory modules are read 321-tr-R by the respective compute element using the synchronous random access transactions 321-tr, and other sets of data 312-D2 that are not cached on the first 320-m1 or second 320-mn memory modules are fetched 331-DL1-fetch from the shared memory pool 312 into the first 320-m1 or the second 320-mn memory module upon demand from the memory module's respective compute element.
In one alternative embodiment to the system 300 just described to cache a shared memory pool 312 using at least two memory modules, further the first 320-m1 memory module is a first dual-in-line-memory-module (DIMM) 300-DIMM-1.
In one possible variation of the alternative embodiment just described, further the first compute element 300-c1 is placed on a first motherboard 300-MB-1, the first dual-in-line-memory-module 300-DIMM-1 is connected to the first motherboard 300-MB-1 via a first dual-in-line-memory-module slot 300-DIMM-1-slot, and the first data link 331-DL1 includes a first optical fiber 307-fiber-1.
In one possible configuration of the possible variation just described, further, the second 320-mn memory module is a second dual-in-line-memory-module 300-DIMM-n, the second compute element 300-cn is placed on a second motherboard 300-MB-n, the second dual-in-line-memory-module 300-DIMM-n is connected to the second motherboard 300-MB-n via a second dual-in-line-memory-module slot 300-DIMM-n-slot, the second data link 331-DLn includes a second optical fiber 307-fiber-n, the first 300-MB-1 and second 300-MB-n motherboard are placed in a first 300-S-1 and a second 300-S-n server, respectively, and the shared memory pool is placed in a third server 300-server thereby facilitating distributed operation and memory disaggregation.
In a second alternative embodiment to the system 300 described above to cache a shared memory pool 312 using at least two memory modules, further the first memory module 320-m1 includes a first random-access memory 320-R1 operative to cache the sets of data 312-D1, a first interface 321-i1 configured to communicate with the first compute element 300-c1 using the synchronous random access transactions 321-tr, and a second interface 321-i2 configured to transact with the external shared memory pool 312 via the first data link 331-DL1.
In a third alternative embodiment to the system 300 described above to cache a shared memory pool 312 using at least two memory modules, further the sets of data 312-D1 and other sets of data 312-D2 are arranged in a page format 312-P1 and 312-Pn, respectively. In some embodiments, the system 300 is further configured to conclude that at least some of the other sets of data 312-D2 are currently not cached on said first memory module 320-m1, to issue in the first compute element 300-c1 a page fault condition, to fetch 331-DL1-fetch by the first compute element 300-c1 at least one page 312-Pn from said shared memory pool 312 where the at least one page 312-Pn contains at least some of the other sets of data 312-D2, and cache the at least one page 312-Pn in said first memory module 320-m1 for further use.
In a fourth alternative embodiment to the system 300 described above to cache a shared memory pool 312 using at least two memory modules, further the first memory module 320-m1 is configured to facilitate the reading 321-tr-R of the sets of data 312-D1 concurrently with the fetching 331-DL1-fetch of the other sets of data 312-D2, such that the fetching 331-DL1-fetch of the other sets of data 312-D2 does not reduce data throughput associated with the readings 321-tr-R.
In one possible variation of the fourth alternative embodiment just described, further, the first memory module 320-m1 comprises a first random-access memory 320-R1 including a first 320-D1 and a second 320-D2 bank of dynamic-random-access-memory (DRAM). In some embodiments, the concurrency is facilitated by the reading 321-tr-R in FIG. 8H made from the first bank 320-D1 in FIG. 8H when the fetching 331-DL1-fetch in FIG. 8H is done with the second bank 320-D2 in FIG. 8H, and by the reading 321-tr-R FIG. 8I made from the second bank 320-D2 in FIG. 8I when the fetching 331-DL1-fetch in FIG. 8I is done with the first bank 320-D1 in FIG. 8I, effectively facilitating operation of the first random-access memory 320-R1 as a dual-ported random-access memory.
One embodiment is a system 400 configured to propagate data among a plurality of compute elements via a shared memory pool 412, including a plurality of compute elements 400-c1, 400-cn associated with, respectively, a plurality of memory modules 420-m1, 420-mn, where each compute element is configured to exchange 409-ex1 data 412-D1 with its respective memory module using synchronous random access memory transactions 421-tr. In this embodiment, further a shared memory pool 412 is connected with the plurality of memory modules 420-m1, 420-mn via a plurality of data links 431-DL1, 431-DLn, respectively. In some embodiments, the system 400 is configured to use the plurality of data links 431-DL1, 431-DLn to further exchange 409-ex2 the data 412-D1 between the plurality of memory modules 420-m1, 420-mn and the shared memory pool 412, such that at least some of the data 412-D1 propagates from one 400-c1 of the plurality of compute elements to the shared memory pool 412 and from the shared memory pool 412 to another one 400-cn of the plurality of compute elements.
One embodiment is a system 500 configured to allow a plurality of compute elements concurrent access to a shared memory pool 512, including a switching network 550 operative to transport concurrently sets of data 512-D1, 512-D2, 512-Dn associated with a plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR. In this embodiment, further a first plurality of data interfaces 529-1, 529-2, 529-n configured to connect, respectively, a plurality of compute elements 500-c1, 500-c2, 500-cn with the switching network 500. In this embodiment, further a shared memory pool 512 including a plurality of memory modules 540-m1, 540-m2, 540-mk, connected to the switching network 550 via a second plurality of data interfaces 523-1, 523-2, 523-k respectively, wherein the shared memory pool 512 is configured to store or serve the sets of data 512-D1, 512-D2, 512-Dn concurrently by utilizing the plurality of memory modules concurrently, thereby facilitating a parallel memory access by the plurality of compute elements 500-c1, 500-c2, 500-cn in conjunction with the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR via the switching network.
One alternative embodiment to the system just described 500 to allow a plurality of compute elements concurrent access to a shared memory pool 512, further including a plurality of servers 500-S-1, 500-S-2, 500-S-n housing respectively the plurality of compute elements 500-c1, 500-c2, 500-cn, and a memory-server 500-S-memory housing the switching network 550 and the second plurality of data interfaces 523-1, 523-2, 523-k. In some embodiments, the first plurality of data interfaces 529-1, 529-2, 529-n includes respectively a plurality of optical fibers 507-fiber-1, 507-fiber-2, 507-fiber-n configured to transport the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR between the plurality of servers 500-S-1, 500-S-2, 500-S-n and the memory-server 500-S-memory. In some embodiments, the at least one of the first plurality of data interfaces 529-1, 529-2, 529-n is a shared input-output medium. In some embodiments, at least one of the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR is done in conjunction with at least one of the plurality of compute elements 500-c1, 500-c2, 500-cn using synchronous random access transactions.
In a second alternative embodiment to the system 500 described above to allow a plurality of compute elements concurrent access to a shared memory pool 512, further the first plurality of data interfaces 529-1, 529-2, 529-n include at least 8 (eight) data interfaces, the plurality of memory modules 540-m1, 540-m2, 540-mk include at least 8 (eight) memory modules, and the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR has an aggregated bandwidth of at least 400 Giga-bits-per-second.
In a third alternative embodiment to the system 500 described above to allow a plurality of compute elements concurrent access to a shared memory pool 512, further each of the plurality of memory modules 540-m1, 540-m2, 540-mk is a dynamic-random-access-memory accessed by the respective one of the second plurality of data interfaces 523-1, 523-2, 523-k using synchronous random access memory transactions, and the latency achieved with each of the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR is lower than 2 (two) microseconds.
In a fourth alternative embodiment to the system 500 described above to allow a plurality of compute elements concurrent access to a shared memory pool 512, further the switching network 550 is a switching network selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, (iii) a cross-bar switching network, and (iv) an integrated-circuit (IC) configured to multiplex said sets of data 512-D1, 512-D2, 512-Dn in conjunction with said plurality of memory modules 540-m1, 540-m2, 540-mk thereby facilitating said transporting concurrently of said sets of data 512-D1, 512-D2, 512-Dn.
In a fifth alternative embodiment to the system 500 described above to allow a plurality of compute elements concurrent access to a shared memory pool 512, further including a second plurality of serves 540-S-1, 540-S-2, 540-S-k housing respectively the plurality of memory modules 540-m1, 540-m2, 540-mk In some embodiments, the second plurality of data interfaces 523-1, 523-2, 523-k includes respectively a plurality of optical fibers 517-fiber-1, 517-fiber-2, 517-fiber-k configured to transport the plurality of memory transactions 512-D1-TR, 512-D2-TR, 512-Dn-TR between the second plurality of servers 540-S-1, 540-S-2, 540-S-k and the switching network 550.
FIG. 11A illustrates one embodiment of a system 600 configured to use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys. The system 600 includes a cache memory 601, and a first compute element 601-c1 associated with and in communicative contact with the cache memory 601. The first compute element 601-c1 includes two or more keys, 618-k1, 618-k2, 618-k3, where each key is associated with a respective data value, 618-k1 with 618-v1, 618-k2 with 618-v2, and 618-k3 with 618-v3. The data values are stored in multiple servers. In FIG. 11A, 618-v1 is stored in first server 618a, 618-v2 is stored in second server 618b, and 618-v3 is stored in third server 618c. It will be understood, however, that two or more specific data values may be served in a single server, although the entire system 600 includes two or more servers. The servers as a whole are a server stack that is referenced herein as a distributed key-value-store (KVS) 621. The first compute element 600-c1 and the distributed KVS 621 are in communicative contact through a switching network 650, which handles requests for data values from the first compute element 600-c1 to the KVS 621, and which handles also data values sent from the KVS 621 to either the first compute element 600-c1 or the cache memory 601. In some embodiments, the system 600 includes also a direct-memory-access (DMA) controller 677, which receives data values from the switching network 650, and which may pass such data values directly to the cache memory 601 rather than to the first compute element 600-c1, thereby temporarily freeing the first compute element 600-c1 to perform work other than receiving and processing a data value. The temporary freeing of the first compute element 600-c1 is one aspect of system 600 timing that facilitates a higher utilization rate for the first compute element 600-c1. In some embodiments, the system 600 includes also a network-interface-card (NIC) 667, which is configured to associate the first compute element 600-c1 and the cache memory 601 with the switching network 650. In some embodiments, the NIC 667 is further configured to block or delay any communication currently preventing the NIC 667 from immediately sending a request for data value from the first compute element 600-c1 to the KVS 621, thereby preventing a situation in which the first compute element 600-c1 must wait before sending such a request. This blocking or delaying by the NIC 667 facilitates efficient usage and a higher utilization rate of the first compute element 600-c1. In FIG. 11A, the order of structural elements between cache memory 601 and first compute element 600-c1 on the one hand and the KVS 621 on the other hand is DMA controller 677, then NIC 667, then switching network 650, but this is only one of many possible configurations, since any of the three elements 677, 667, or 650, may be either on the left, or in the middle, or on the right, and indeed in alternative embodiments, the DMA controller 677 and NIC 667 may be parallel, such that they are not in direct contact with one another but each one is in contact with the switching network 667 and with either the cache memory 601 or the first compute element 600-c1 or with both the cache memory 601 and the first compute element 600-c1.
In some embodiments of FIG. 11A, the KVS 621 is a shared memory pool 512 from FIG. 10B, which includes multiple memory modules 540-m1, 540-m2, 540-mk, where each memory module is associated with a particular server. In FIG. 11A as shown, memory module 540-m1 would be associated with first server 618a, memory module 540-m2 would be associated with second server 618b, and memory module 540-mk would be associated with third server 618c. However, many different configurations are possible, and a single server may include two or more memory modules, provided that the entire system includes a multiplicity of memory modules and a multiplicity of servers, and that all of the memory modules are included in at least two servers. In a configuration with memory modules, the data values are stored in the memory modules, for example data value 618-v1 in memory module 540-m1, data value 618-v2 in memory module 540-m2, and data value 618-v3 in memory module 540-mk, but this is only one of multiple possible configurations, provided that all of the data values are stored in two or more memory modules that are located in two or more servers. In some embodiments, one or more of the multiple memory modules 540-m1, 540-m2, 540-mk, are based on random-access-memory (RAM), which may be a dynamic RAM (DRAM) or a flash memory in two non limiting examples, and at least as far as read cycles are concerned, thereby facilitating the execution of data value requests from the first compute element 600-c1. In some embodiments, a memory module can execute a data value request in a period between 200 and 2,500 nanoseconds.
FIG. 11B illustrates one embodiment of a system configured to request and receive data values needed for data processing. FIG. 11B illustrates two transfers of information, one at the top and one at the bottom, although both transfers pass through the switching network 650. At the top, cache memory 601 receives 618-get1 a first data value 618-v1 which was sent by the first server 618a to the switching network 650. In some embodiments, the first data value 618-v1 is sent directly from the switching network to the cache memory 601, while in other embodiments the first data value 618-v1 is sent from the switching network to a DMA controller 677 (or rather pulled by the DMA controller) and then to the cache memory 601, while in other embodiments the first data value 618-v1 is sent from the switching network 650 directly to the first compute element 600-c1, and in other embodiments the first data value 618-v1 is sent from the switching network 650 to a DMA controller 677 and then to the first compute element 600-c1.
In FIG. 11B, in the bottom transfer of information, a first compute element 600-c1 uses a key, here 618-k2 to identify the server location of a needed data value, here second data value 618-v2. The first compute element 600-c1 then sends a request 600-req2 to receive this data value 618-v2, where such request 600-req2 is sent to the switching network 650 and then to the server holding the data value 618-v2, here second server 618b. 
FIG. 11C illustrates one embodiment of a system configured to streamline a process of retrieving a plurality of values from a plurality of servers using a plurality of keys. In FIG. 11C, the system 600 is configured to perform four general tasks:

    
    
        to use keys 618-k2, 618-k3, to derive 600-c1-der-s2, 600-c1-der-s3 identities of servers holding needed data values,
        to send requests 600-req2, 600-req3 for needed data values to the specific servers in the KVS 621 holding the needed data values, to receive the needed data values 618-get1, 618-get2 from the servers via the switching network 650 or the DMA controller 677 or the cache memory 601, and
        to process 600-c1-pro-v1, 600-c1-pro-v2 the received data values as required.

In some embodiments, the first compute element 600-c1 is dedicated to the four general tasks described immediately above. Dedications to these tasks can enhance the utilization rate of the first compute element 600-c1, and thereby increase the relative efficiency of its usage.

    
    


In the specific embodiment shown in FIG. 11C, time flows from the top to the bottom, actions of the first compute element 600-c1 are illustrated on the left, actions of the second server 618b are illustrated on the right, and interactions between the first compute element 600-c1 and the second server 618b are illustrated by lines pointing between these two structures in which information transfers are via the switched network 650. The server location (e.g. the address of the server) associated with a second needed data value is derived 600-c1-der-s2 by the first compute element 600-c1, after which the first compute element 600-c1 receives 618-get1 a first needed data value that was previously requested, and the first compute element 600-c1 sends a new request for a second needed data value 600-req2 to the second server 618b, after which the first compute element 600-c1 processes the first data value 600-c1-pro-v1, and the first compute element derives the server location of a third needed data value 600-c1-der-s3, after which the first compute element 600-c1 receives 618-get2 the second needed data value, and the first compute element sends a future request 600-req3 for the third needed data value, after which the first compute element processes the second needed data value 60-c1-pro-v2.
After the second server 618b receives from the switching network 650 the new request for a second needed data value 600-req2, the second server 618b executes this request 600-req2-exe by locating, optionally using the second key which is included in the new request 600-req2, the needed data value within the server 618b and preparing to send it to the switching network 650. The period of time from which the first compute element 600-c1 sends a new request for a second needed data value 600-req2 until that request is received by the second server 618b is a request propagation time 600-req2-prop. During the propagation period 600-req2-prop, the period during which the second server 618b executes the data request 600-req2-exe, and the time period 618-get2 during which the second needed data value is transferred from the second server 618b to the first compute element 600-c1, the first compute element 600-c1 processes the first needed data value 600-c1-pro-v1 and, in a first period 699, derives the server location of the third needed data value 600-c1-der-s3. This interleaving of activity between the various structural elements of the system 600 increases the utilization rate of the first compute element 600-c1 and thereby enhances the efficient usage of the first compute element 600-c1.
In the embodiment illustrated in FIG. 11C, processing of the first needed data value 600-c1-pro-v1 occurs before the derivation of server location for the third needed data value 600-c1-der-s3. This is only one of multiple embodiments. In some alternative embodiments, the derivation of server location for the third needed data value 600-c1-der-s3 occurs before the processing of the first needed data value 600-c1-pro-v1. In other alternative embodiments, the processing of the first needed data value 600-c1-pro-v1 occurs in parallel with the derivation of the server location for the third needed data value 600-c1-der-s3. All of these embodiments are possible, because in all of them the first compute element 600-c1 continues to be utilized, which means that the first compute element's 600-c1 utilization rate is relatively high, and therefore its usage is relatively efficient.
FIG. 11D illustrates one embodiment of a system configured to minimize or at least reduce the duration of time periods between general tasks executed by a first compute element. In some embodiments, a first compute element 600-c1 is dedicated to the four general tasks described with respect to FIG. 11C above. In the specific embodiment illustrated in FIG. 11D, a first compute element 600-c1 is operating over time. The first compute element 600-c1 receives 618-get1 a first needed data value. There is a second period 698 after receipt 618-get1 of the first needed data value but before the first compute element 600-c1-prov-v1 processes that first needed data value. There is then a third period 697 after the first compute element 600-c1 has processed the first needed data value 600-c1-pro-v1 but before the first compute element 600-c1 derives the server location of a third needed data value 600-c1-der-s3. To increase system efficiency, it would be desirable to minimize, or at least to reduce the duration, of either or both of the second period 698 and the third period 697. The implementation of the four general tasks by the first compute element 600-c1, as presented and explained in reference to FIG. 11C, will minimize or at least reduce the duration of either or both of the second period 698 and the third period 697, and in this way increase the utilization rate of the first compute element 600-c1 and hence the relative efficiency in the usage of the first compute element 600-c1. In some alternative embodiments, the first compute element 600-c1 derives the server location of a third needed data value 600-c1-der-s3 before it processes the first needed data value 600-c1-pro-v1, in which case the second period 698 is between 618-get1 and 600-c1-der-s3 and the third period 697 is immediately after 600-c1-pro-v1.
FIG. 11E illustrates one embodiment of a system configured to increase the utilization rate of a first compute element. In some embodiments, a first compute element 600-c1 is dedicated to the four general tasks described with respect to FIG. 11C above. In the specific embodiment illustrated in FIG. 11E, a first compute element 600-c1 is operating over time. After sending a new request for a second needed data value 600-req2, the first compute element 600-c1 processes the first needed data value 600-c1-pro-v1 and derives the server location of a third needed data value 600-c1-der-s3, either in the order shown in FIG. 11E, or by deriving the third needed data value 600-c1-der-s3 prior to processing the first needed data value 600-c1-pro-v1, or by performing both operations in a parallel manner. The duration of time during which the first compute element 600-c1 both processes the first needed data value 600-c1-pro-v1 and derives the server location of the third needed data value 600-c1-der-s3, in whatever chronological order, is period 696. In one embodiment, as a result of one or more of the dedication of the first compute element 600-c1 to the four general tasks, and/or the simultaneous operation of the first compute element 600-c1 and the second server 618b as illustrated and described in FIG. 11C, and/or of the operation of the cache memory in receiving some of the data values as illustrated and described in FIG. 11A, the first compute element 600-c1 consumes at least 50 (fifty) percent of the time during period 696 performing the two tasks 600-c1-pro-v1 and 600-c1-der-s3. This is a relatively high computational duty-cycle, and it allows the first compute element 600-c1 to process a plurality of keys, 618-k1, 618-k2, 618-k3 from FIG. 11A, and a plurality of values, 618-v1, 618-v2, 618-v3, from FIG. 11A, at an increased and relatively high rate, thus enhancing the relative efficiency of the first compute element 600-c1.
FIG. 11F illustrates one embodiment of a system configured to achieve a relatively high computational duty-cycle by at least temporarily blocking or redirecting the execution of certain processes. In FIG. 11F, there is a central-processing-unit (CPU) 600-CPU that includes at least a cache memory 601, a first compute element 600-c1, and a second compute element 600-c2. The first compute element 600-c1 includes a plurality of keys, 618-k1, 618-k2, 618-k3, each of which is associated with a corresponding data value stored in a server (such data values and servers not shown in FIG. 11F). The first compute element 600-c1 executes the general tasks illustrated and described in FIG. 11C. The second compute element 600-c2 executes certain processes that are unrelated 600-pr to the general tasks executed by the first compute element 600-c1. The system includes also an operating system 600-OS configured to control and manage the first 600-c1 and second 600-c2 compute elements. The operating system 600-OS is further configured to manage the general tasks executed by the first compute element 600-c1 and the unrelated processes 600-pr that are executed by the second compute element 600-c2. The operating system 600-OS is further configured to help achieve dedication of the first compute element 600-c1 to the general tasks by blocking the unrelated processes 600-pr from running on the first compute element 600-c1, or by causing the unrelated processes 600-pr to run on the second compute element 600-c2, or both blocking or directing to the second compute element 600-c2 depending on the specific process, or on the time constraints, or upon the system characteristics at a particular point in time.
In one embodiment, at least part of cache memory 601 is dedicated for usage by only the first compute element 600-c1 in conjunction with execution of the general tasks illustrated and described in FIG. 11C, thus ensuring performance and timing in accordance with some embodiments.
It will be understood that the particular embodiment illustrated in FIG. 11F is only one of multiple possible embodiments. In some alternative embodiments, there is only a single compute element, but some of its sub-structures are dedicated to the general tasks illustrated and described in FIG. 11C, whereas other of its sub-structures executed unrelated processes. In some alternative embodiments, there are two compute elements, in which some sub-structures of a first compute element 600-c1 are dedicated to general tasks while others execute unrelated tasks, and similarly some sub-structures of a second compute element 600-c2 are dedicated to general tasks while others execute unrelated tasks. In some alternative embodiments, different sub-structures within a compute element are either dedicated to general tasks or execute unrelated processes, but the status of a particular sub-structure will change over time depending on system characteristics, processing demands, and other factors, provided that every instant of time there are some sub-structures that perform only general tasks while other sub-structures execute only unrelated processes.
One embodiment is a system 600 operative to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, including a first compute element 600-c1 associated with a first cache memory 601, and a distributed key-value-store (KVS) 621 including a plurality of servers 618a, 618b, 618c configured to store a plurality of values 618-v1, 618-v2, 618-v3 associated with a plurality of keys 618-k1, 618-k2, 618-k3, in which the plurality of servers is communicatively connected with said first cache memory 601 via a switching network 650. Further, the system is configured to send, from the first compute element 600-c1, to a second 618b of the plurality of servers identified 600-c1-der-s2 using a second 618-k2 plurality of keys, via said switching network 650, a new request 600-req2 to receive a second 618-v2 of the plurality of values associated with the second key 618-k2. Further, the system is configured to receive 618-get1, via said switching network 650, from a first 618a of said plurality of servers, into said first cache memory 601, a first 618-v1 of said plurality of values previously requested. Further, after completion of the operations just described, the system is further configured to process 600-c1-pro-v1 in the first compute element 600-c1, in conjunction with the first cache memory 601, the first value 618-v1 received, simultaneously with the second server 618b and switching network 650 handling the new request 600-req2. The system is further configured to derive 600-c1-der-s3, in the first compute element 600-c1, from a third 618-k3 plurality of keys, during a first period 699 prior to receiving 618-get2 and processing 600-c1-pro-v2 the second value 618-v2, an identity of a third 618c of the plurality of servers into which to send a future request 600-req3 for a third 618-v3 of said plurality of values, thereby facilitating said efficient usage.
In one alternative embodiment to the system just described to efficiently use a compute element, the handling includes (i) propagation 600-req2-prop of the new request 600-req2 via the switching network 650, and (ii) executing 600-req2-exe the new request 600-req2 by the second server 618b. 
In one possible configuration of the alternative embodiment just described, (i) the propagation 600-req2-prop takes between 150 to 2,000 nanoseconds, (ii) the executing 600-req2-exe of the new request 600-req2 takes between 200 and 2,500 nanoseconds, and (iii) the processing 600-c1-pro-v1 takes between 500 and 5,000 nanoseconds. In this way, the processing 600-c1-pro-v1 may extends over a period that is similar in magnitude to the handling, thereby making said simultaneity possibly more critical for achieving the efficient usage. In one possible embodiment of the possible configuration described herein, the distributed key-value-store 621 is a shared memory pool 512 that includes a plurality of memory modules 540-m1, 540-m2, 540-mk, wherein each of the plurality of servers 618a, 618b, 618c is associated with at least one of said plurality of memory modules 540-m1, 540-m2, 540-mk, and wherein the plurality of values 618-v1, 618-v2, 618-v3 are stored in the plurality of memory modules 540-m1, 540-m2, 540-mk. 
In possible variation of the possible configuration described above, the plurality of memory modules 540-m1, 540-m2, 540-mk are based on random-access-memory, thereby facilitating the executing 600-req2-exe of the new request 600-req2 taking between 200 and 2,500 nanoseconds. This possible variation may be implemented whether or not the distributed key-value-store 621 is a shared memory pool 512.
In a second alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, the system 600 is further configured to dedicate the first compute element 600-c1 for: (i) sending any one of the requests 600-req2, 600-req3 to receive respectively any one of the plurality of values 618-v2, 618-v3, (ii) processing 600-c1-pro-v1, 600-c1-pro-v2 any one of the plurality of values 618-v1, 618-v2, and (iii) deriving 600-c1-der-s2, 600-c1-der-s3 identities of any one of the plurality of servers 618b, 618c using respectively any one of the plurality of keys 618-k2, 618-k3. In this way, there are minimized at least: (i) a second period 698 between the receiving 618-get1 and the processing 600-c1-pro-v1, and (ii) a third period 697 between the processing 600-c1-pro-v1 and the deriving 600-c1-der-s3. This minimization of (i) and (ii) facilitates the efficient usage of a compute element 600-c1.
In a first variation to the second alternative embodiment described above, The system further includes a second compute element 600-c2, together with the first compute element 600-c1 belonging to a first central-processing-unit (CPU) 600-CPU, and an operating-system (OS) 600-OS configured to control and manage the first 600-c1 and second 600-c2 compute element, wherein the operating-system 600-OS is further configured to manage a plurality of processes comprising: (i) said sending 600-req2, receiving 618-get1, processing 600-c1-pro-v1, and deriving 600-c1-der-s3, and (ii) other unrelated processes 600-pr. Also, the operating-system 600-OS is further configured to achieve the dedication by blocking the other unrelated processes 600-pr from running on said first compute element 600-c1, and by causing the other unrelated processes 600-pr to run on the second compute element 600-c2.
In a second variation to the second alternative embodiment described above, as a result of the dedication, the simultaneity, and the first cache memory 601, the derivation 600-c1-der-s3 and the processing 600-c1-pro-v1 together account for at least 50 (fifty) per-cent of time spent by the first compute element 600-c1 over a period 696 extending from a beginning of said sending 600-req2 to an end of said deriving 600-c1-der-s3. This utilization rate thereby achieves a high computational duty-cycle, which thereby allows the first compute element 600-c1 to process the plurality of keys 618-k1, 618-k2, 618-k3 and values 618-v1, 618-v2, 618-v3 at an increased rate.
In a first configuration to the second variation to the second alternative embodiment, described above, further the period 696 extending from the beginning of the sending to the end of the deriving, is less than 10 (ten) microseconds.
In a second configuration to the second variation to the second alternative embodiment, described above, further the increased rate facilitates a sustained transaction rate of at least 100,000 (one hundred thousand) of the plurality of keys and values per second.
In a third alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, further the derivation is done by applying on the third key 618-k3 a technique selected from a group consisting of: (i) hashing, (ii) table-based mapping, and (iii) any mapping technique either analytical or using look-up tables.
In a fourth alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, further the first compute element 600-c1 and the first cache memory 601 belong to a first central-processing-unit (CPU) 600-CPU, such that the first compute element 600-c1 has a high bandwidth access to the first cache memory 601, thereby allowing the processing 600-c1-pro-v1 to conclude in less than 5 (five) microseconds.
In one possible configuration of the fourth alternative embodiment just described, the high bandwidth is more than 100 (one hundred) Giga-bits-per-second.
In a fifth alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, the system further comprises a direct-memory-access (DMA) controller 677 configured to receive 618-get1 the first value 618-v1 via the switching network 650 directly into the first cache memory 601.
In one a variation of the fifth alternative embodiment just described, further the direct-memory-access controller 677 frees the first compute element 600-c1 to perform the identification 600-c1-der-s2 of the second server 618b simultaneously with the receiving 618-get1 of the first value 618-v1. In this way, the efficient usage is facilitated.
In a sixth alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, the system 600 is further configured to send to the third 618c of the plurality of servers identified, via said switching network 650, the future request 600-req3 to receive the third value 618-v3, and to receive 618-get2, via the switching network 650, from the second server 618b, into the first cache memory 601, the second value 618-v2. The system is also configured, after completion of the send and receive operations just described, to process 600-c1-pro-v2 the second value 618-v2 received, simultaneously with the third server 618c and switching network 650 handling of the future request 600-req3.
In a seventh alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, system 600 further comprises a network-interface-card (NIC) 667 configured to associate the first compute element 600-c1 and the first cache memory 601 to the said switching network 650. Also, the network-interface-card 667 is further configured to block or delay any communication currently preventing the network-interface-card 667 from immediately performing the sending 600-req2, thereby preventing the first compute element 600-c1 from waiting before performing said sending, thereby facilitating the efficient usage of the first compute element 600-c1.
In an eighth alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, further the deriving 600-c1-der-s3 is done simultaneously with the second server 618b and the switching network 650 handling of the new request 600-req2.
In a ninth alternative embodiment to the system described above to efficiently use a compute element to process a plurality of values distributed over a plurality of servers using a plurality of keys, the system 600 further comprises a direct-memory-access (DMA) controller 677 configured to receive 618-get2 the second value 618-v2 via the switching network 650 directly into the first cache memory 601, wherein the direct-memory-access controller 677 frees the first compute element 600-c1 to perform the processing 600-c1-pro-v1 simultaneously with the receiving 618-get2 of the second value 618-v2. The operation described in this ninth alternative embodiment thereby facilitates efficient usage of the first compute element 600-c1.
In the various system embodiment described above, the processing 600-c1-pro-v1 is depicted as occurring before the deriving 600-c1-der-s3. However, this particular order of events is not required. In various alternative embodiments, the deriving 600-c1-der-s3 occurs before the processing 600-c1-pro-v1. Also, in different alternative embodiments, the deriving 600-c1-der-s3 occurs in parallel with the processing 600-c1-pro-v1.
FIG. 12 illustrates one embodiment of a method for mixing and timing, relatively efficiently, at least two key-value transactions in conjunction with a distributed key-value-store (KVS) 621. In step 1031: a direct-memory-access (DMA) controller 677, starts a first process of receiving 618-get1 via a switching network 650, from a first 618a of a plurality of servers 618a, 618b, 618c directly into a first cache memory 601 associated with a first compute element 600-c1, a first 618-v1 of a plurality of values 618-v1, 618-v2, 618-v3 previously requested and associated with a first 618-k1 of a plurality of keys 618-k1, 618-k2, 618-k3. In step 1032: a first compute element 600-c1 derives 600-c1-der-s2 from a second 618-k2 of the plurality of keys, simultaneously with at least one part of the first process, an identity of a second 618b of the plurality of servers into which to send a new request 600-req2 for a second 618-v2 of said plurality of values. In step 1033: the first compute element 600-c1 sends, via the switching network 650, to the second server 618b identified, the new request 600-req2. In step 1034: the direct-memory-access controller 677 finishes the first process of receiving 618-get1 the requested data element. In step 1035: the first compute element 600-c1 processes 600-c1-pro-v1 the first value 618-v1 received, simultaneously with the second server 618b and the switching network 650 handling the new request 600-req2.
In a first alternative embodiment to the method just described, further the first compute element 600-c1 derives 600-c1-der-s3 from a third of the plurality of keys 618-k3, during a first period 699 prior to receiving 618-get2 and processing 600-c1-pro-v2 the second value 618-v2, an identity of a third 618c of the plurality of servers into which to send a future request 600-req3 for a third 618-v3 of the plurality values.
FIG. 13A illustrates one embodiment of a system 680 configured to interleave high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran over a shared input-output medium 685. The system 680 includes a plurality of values 618-v1, 618-v2, 618-v3, distributed over a plurality of servers 618a, 618b, 618c, using a plurality of keys 618-k1, 618-k2, 618-k3. The system 680 includes a cache memory 601, and a first compute element 600-c1 associated with and in communicative contact with the cache memory 601. The first compute element 600-c1 includes two or more keys, 618-k1, 618-k2, 618-k3, where each key is associated with a respective data value, 618-k1 with 618-v1, 618-k2 with 618-v2, and 618-k3 with 618-v3. The data values are stored in multiple servers. In FIG. 13A, 618-v1 is stored in first server 618a, 618-v2 is stored in second server 618b, and 618-v3 is stored in third server 618c. It will be understood, however, that two or more specific data values may be served in a single server, although the entire system 680 includes two or more servers. The servers as a whole are a server stack that is referenced herein as a distributed key-value-store (KVS) 621.
The first compute element 600-c1 and the distributed KVS 621 are in communicative contact through a shared input-output medium 685 and a medium controller 685-mc, which together handle requests for data values from the first compute element 600-c1 to the KVS 621, and which handle also data values sent from the KVS 621 to either the first compute element 600-c1 or to the cache memory 601. In some embodiments, the system 680 includes also a direct-memory-access (DMA) controller 677, which receives data values from the shared input-output medium 685 and medium controller 685-mc, and which may pass such data values directly to the cache memory 601 rather than to the first compute element 600-c1, thereby at least temporarily freeing the first compute element 600-c1.
In some embodiments illustrated in FIG. 13A, the KVS 621 is a shared memory pool 512 from FIG. 10B, which includes multiple memory modules 540-m1, 540-m2, 540-mk, and wherein one of the memory modules is configured to store the first value 618-v1. In some embodiments, the multiple memory modules 540-m1, 540-m2, 540-mk, are based on random-access-memory, thereby facilitating fast extraction of at least the desired value 618-v1. In some embodiments, “fast extraction” can be executed in less than 3 (three) microseconds. In some embodiments, the blocking of lower priority transactions 686-tran enables sending of the new request 600-req2 from FIGS. 11B and 11C in less than 3 (three) microseconds, thereby matching timing of the extraction, and consequently thereby facilitating overall fast key-value transactions 618-kv-tran, each such fast transaction taking less than 10 (ten) microseconds.
FIG. 13B illustrates one embodiment of a system configured to interleave high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran over a shared input-output medium, in which both types of transactions are packet-based transactions and the system is configured to stop packets of the lower priority transactions 686-tran in order to commence communication of packets of the high priority transactions 681-kv-tran. In FIG. 13B, the first transaction processed by the system is one of a plurality of low priority transactions 686-tran, including packets P1, P2, and Pn at the top of FIG. 13B, and the second transaction processed by the system is one of a plurality of high priority key-value transactions 681-kv-tran, including packets P1, P2, and Pn at the bottom of FIG. 13B. In the particular embodiment illustrated in FIG. 13B, all of the transactions are packet-based transactions, and they are performed via a medium controller in the system 685-mc from FIG. 13A in conjunction with a shared input-output medium 685 from FIG. 13A. The medium controller 685-mc is configured to stop 686-stop the on-going communication of a first packet 686-tran-first-P belonging to one of the lower priority transactions 686-tran, and immediately thereafter to commence communication of a second packet 681-kv-second-P belonging to one of the high priority key-value transactions 681-kv-tran. After the second packet 681-kv-tran-second-P has been communicated, the medium controller 685-mc is configured to resume 686-resume communication of the first packet 686-tran-first-P.
FIG. 13C illustrates one embodiment of part of a system configured to interleave high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran over a shared input-output medium, comprising a network-interface-card (NIC) 685-NIC including a medium-access-controller (MAC) 685-mac. In FIG. 13C, a shared input-output medium 685 from FIG. 13A is a network-interface-card 685-NIC together with a medium-access-controller (MAC) 685-mac that is located on the network-interface-card (NIC) 685-NIC. The elements shown help communicate both high priority key-value transactions 681-kv-tran and lower priority transactions 686-tran, either of which may be communicated either (i) from a KVS 621 to a cache 601 or first compute element 600-c1, or (ii) from a cache 601 or first compute element 600-c1 to a KVS 621. The lower priority transactions 686-tran are not necessarily related to KVS 621, and may be, as an example, a general network communication unrelated with keys or values.
One embodiment is a system 680 configured to interleave high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran over a shared input-output medium 685, including a shared input-output medium 685 associated with a medium controller 685-mc, a central-processing-unit (CPU) 600-CPU including a first compute element 600-c1 and a first cache memory 601, and a key-value-store (KVS) 621 communicatively connected with the central-processing-unit 600-CPU via the shared input-output medium 685. Further, the central-processing-unit 600-CPU is configured to initiate high priority key-value transactions 681-kv-tran in conjunction with the key-value-store (KVS) 621 said shared input-output medium 685, and the medium controller 685-mc is configured to block lower priority transactions 686-tran via the shared input-output medium 685 during at least parts of the high priority key-value transactions 681-kv-tran, thereby achieving the interleaving without delaying the high priority key-value transactions 681-kv-tran. 
In one alternative to the system 680 to interleave transactions, further the key-value-store (KVS) 621 is configured to store a first value 618-v1 associated with a first key 618-k1. Further, the high priority key-value transactions 681-kv-tran include at least a new request 600-req2 from FIGS. 11B and 11C for the first value 618-v1, wherein the new request 600-req2 is sent from the first compute element 600-c1 to the key-value-store 621 via the shared input-output medium 685, and the new request 600-req2 conveys the first key 618-k1 to the key-value-store 621.
In some embodiments, the key-value-store (KVS) 621 is a distributed key-value-store, including a plurality of servers 618a, 618b, 618c. In some forms of these embodiments, the distributed key-value-store is a shared memory pool 512 including a plurality of memory modules 540-m1, 540-m2, 540-mk, wherein one of the plurality of memory modules is configured to store the first value 618-v1. In some forms of these embodiments, the plurality of memory modules 540-m1, 540-m2, 540-mk are based on random-access-memory, thereby facilitating fast extraction of at least the first value 618-v1. In some forms of these embodiments, “fast extraction” is done in less than 3 (three) microseconds. In some forms of these embodiments, the blocking of lower priority transactions 686-tran enables sending of the new request in less than 3 (three) microseconds, thereby matching timing of the extraction, thereby consequently facilitating overall fast key-value transactions, each transaction taking less than 10 (ten) micro second.
In a second alternative to the system 680 to interleave transactions, further the high priority key-value transactions 681-kv-tran are latency-critical key-value transactions, and the medium controller 685-mc is configured to interrupt any of the lower priority transactions 686-tran and immediately commence at least one of the high priority key-value transactions 681-kv-tran, thereby facilitating said latency criticality.
In one possible configuration of the second alternative embodiment just described, further both the high priority key-value transaction 681-kv-tran and the lower priority transactions 686-tran are packet-based transactions performed via the medium controller 685-mc in conjunction with the shared input-output medium 685. Further, the medium controller 685-mc is configured to stop 686-stop on-going communication of a first packet 686-tran-first-P belonging to the lower priority transactions 686-tran via the shared input-output medium 685, and immediately to commence communication of a second packet 681-kv-tran-second-P belonging to the high priority key-value transaction 681-kv-tran via the shared input-output medium 685 instead, thereby achieving the communication interruption at the packet level.
In one possible variation of the configuration just described, the medium controller 685-mc is configured to resume 686-resume communication of the first packet 686-tran-first-P after the second packet 681-kv-tran-second-P has finished communicating, thereby facilitating packet fragmentation.
In a third alternative to the system 680 to interleave transactions, further the shared input-output medium is based on an interconnect element selected from a group consisting of: (i) peripheral-component-interconnect-express (PCIE) computer expansion bus 105-pcie from FIG. 3A, (ii) Ethernet 105-eth from FIG. 3B, and (iii) a network-interface-card (NIC) 685-NIC.
In some embodiments associated with the PCIE computer expansion bus 105-pcie from FIG. 3A, the medium controller 685-mc may be implemented as part of a root-complex 105-root from FIG. 3A associated with the PCIE computer expansion bus 105-pcie. 
In some embodiments associated with the Ethernet 105-eth from FIG. 3B, the medium controller 685-mc may be implemented as part of a media-access-controller (MAC) 105-mac from FIG. 3B associated with the Ethernet 105-eth. 
In some embodiments associated with the NIC 685-NIC, the medium controller 685-mc may be implemented as part of a media-access-controller (MAC) 685-mac associated with the NIC 685-NIC. In some forms of these embodiments, the NIC 685-NIC is in compliance with Ethernet.
In a fourth alternative to the system 680 to interleave transactions, further both the high priority key-value transactions 681-kv-tran and the lower priority transactions 686-tran are packet-based transactions performed via the medium controller 685-mc in conjunction with the shared input-output medium 685. Further, the medium controller 685-mc is configured to deny access to the shared input-output medium 685 from a first packet 686-tran-first-P belonging to the lower priority transactions 686-tran, and instead grant access to the shared input-output medium 685 to a second packet 681-kv-tran-second-P belonging to the high priority key-value transactions 681-kv-tran, thereby giving higher priority to the high priority key-value transactions 681-kv-tran over the lower priority transactions 686-tran. 
In a fifth alternative to the system 680 to interleave transactions, further the key-value-store 621 is configured to store a first value 618-v1 associated with a first key 618-k1. Further, the high priority key-value transactions 681-kv-tran include at least sending of the first value 618-v1 from the key-value-store (KVS) 621 to the central-processing-unit 600-CPU via the shared input-output medium 685.
In one possible configuration of the fifth alternative just described, the system includes further a direct-memory-access (DMA) controller 677 configured to receive the first value 618-v1 via the shared input-output medium 685 directly into the first cache memory 601.
In a sixth alternative embodiment to the system 680 to interleave transactions, further the shared input-output medium 685 includes an electro-optical interface 107-a from FIG. 5A and an optical fiber 107-fiber-ab from FIG. 5A which are operative to transport the high priority key-value transactions 681-kv-tran and the lower priority transactions 686-tran. 
FIG. 14A illustrates one embodiment of a method for mixing high priority key-value transactions 681-kv-tran over a shared input-output medium 685, together with lower priority transactions 686-tran over the same shared input-output medium 685, without adversely affecting system performance. In step 1041, a medium controller 685-mc associated with a shared input-output medium 685 detects that a second packet 681-kv-tran-second-P associated with high priority key-value transactions 681-kv-tran is pending; meaning, as an example, that the second packet 681-kv-tran-second-P has been recently placed in a transmission queue associated with the input-output medium 685.
In step 1042, as a result of the detection, the medium controller 685-mc stops handling of a first packet 686-tran-first-P associated with a lower priority transactions 686-tran via the shared input-output medium 685. In step 1043, the medium controller 685-mc commences transmission of the second packet 681-kv-tran-second-P via said shared input-output medium 685, thereby preventing the lower priority transactions 686-tran from delaying the high priority key-value transaction 681-kv-tran. 
In a first alternative to the method just described for mixing high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran, further the prevention leads to a preservation of timing performance of the high priority key-value transactions 681-kv-tran, wherein such timing performance is selected from a group consisting of: (i) latency of the high priority key-value transactions 681-kv-tran, and (ii) bandwidth of the high priority key-value transactions 681-kv-tran. 
In a second alternative to the method described for mixing high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran, further the prevention leads to a preservation of latency of the high priority key-value transactions 681-kv-tran, and as a result, such latency of the high priority key-value transactions 681-kv-tran is shorter than a time required to transmit a shortest packet belonging to said lower priority transactions 686-tran. 
FIG. 14B illustrates one embodiment of a method for mixing high priority key-value transactions 681-kv-tran over a shared input-output medium 685, together with lower priority transactions 686-tran over the same shared input-output medium 685, without adversely affecting system performance. In step 1051, a medium controller 685-mc associated with a shared input-output medium 685 detects that a second packet 681-kv-tran-second-P associated with high priority key-value transactions 681-kv-tran is pending. In step 1052, as a result of the detection, the medium controller 685-mc delays handling of a first packet 686-tran-first-P associated with a lower priority transactions 686-tran via the shared input-output medium 685. In step 1053, the medium controller 685-mc transmits the second packet 681-kv-tran-second-P via said shared input-output medium 685, thereby preventing the lower priority transactions 686-tran from delaying the high priority key-value transaction 681-kv-tran. 
In a first alternative to the method just described for mixing high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran, further the prevention leads to a preservation of timing performance of the high priority key-value transactions 681-kv-tran, wherein such timing performance is selected from a group consisting of: (i) latency of the high priority key-value transactions 681-kv-tran, and (ii) bandwidth of the high priority key-value transactions 681-kv-tran. 
In a second alternative to the method described for mixing high priority key-value transactions 681-kv-tran together with lower priority transactions 686-tran, further the prevention leads to a preservation of latency of the high priority key-value transactions 681-kv-tran, and as a result, such latency of the high priority key-value transactions 681-kv-tran is shorter than a time required to transmit a shortest packet belonging to lower priority transactions 686-tran. 
FIG. 14C illustrates one embodiment of a method for reducing latency associated with key-value transactions 686-dv-tran involving a distributed data store interconnected by a network. In step 1061, a first network-interface-card (NIC) 685-NIC receives, from a first compute element 600-c1, a new request 600-req2 from FIGS. 11B and 11C to extract with high priority a first value 618-v1 associated with a first key 618-k1. In step 1062, consequently the first network-interface-card 685-NIC delays a lower priority transaction 686-tran or other network-related activity that prevents or that might prevent, the first network-interface-card 685-NIC from immediately communicating the first key 618-k1 to a destination server 618a storing the first value 618-v1 and belonging to a key-value-store 621 comprising a plurality of servers 618a, 618b, 618c. In step 1063, as a result of such delaying, the first network-interface card 685-NIC communicates immediately the first key 618-k1 to the destination server 618a, thereby allowing the destination server 618a to start immediately processing of the first key 618-k1 as required for locating, within the destination server 618a, the first value 618-v1 in conjunction with said new request 600-req2. It is understood that the phrase “lower priority transaction 686-tran or other network-related activity” includes the start of any lower priority transaction 686-tran, a specific packet in the middle of a lower priority transaction 686-tran which is delayed to allow communication of a high priority transaction 681-kv-tran or of any packet associated with a high priority transaction 681-kv-tran, and any other network activity that is not associated with the high priority transaction 681-kv-tran and that could delay or otherwise impede the communication of a high priority transaction 681-kv-tran or any packet associated with a high priority transaction 681-kv-tran. 
In one embodiment, said delaying comprises prioritizing the new request 600-req2 ahead of the lower priority transaction 686-tran or other network-related activity, such that lower priority transaction 686-tran or other network related activity starts only after the communicating of the first key 618-k1.
One embodiment is a system 680 (FIG. 13A) configured to facilitate low latency key-value transactions, including: a shared input-output medium 685 associated with a medium controller 685-mc; a central-processing-unit (CPU) 600-CPU; and a key-value-store 621 comprising a first data interface 523-1 (FIG. 10B) and a first memory module 540-m1 (FIG. 10B), said first data interface is configured to find a first value 618-v1 (FIG. 13A) in said first memory module and extract said first value from said first memory module using random access read cycles, and said key-value-store 621 is communicatively connected with said central-processing-unit 600-CPU via said shared input-output medium 685. In one embodiment, the central-processing-unit 600-CPU is configured to initiate a high priority key-value transaction 681-kv-tran (FIG. 13A) in conjunction with said key-value-store 621, by sending to said key-value-store, via said shared input-output medium 685, a new request 600-req2 (FIG. 11C) for said first value 618-v1, said new request comprising a first key 618-k1 associated with said first value and operative to facilitate said finding; and the medium controller 685-mc is configured to block lower priority transactions 686-tran via said shared input-output medium 685, thereby preventing said lower priority transactions from delaying said new request 600-req2, thereby allowing the system to minimize a time between said sending of the new request to said extraction of the first value 618-v1. In one embodiment, said prevention of delay and said random access read cycles together result in said minimization, such that said time between said sending of the new request 600-req2 to said extraction of the first value 618-v1 is kept below 5 (five) microseconds. In one embodiment, as a result from said minimization, said high priority key-value transaction 681-kv-tran results in the delivery of said first value 618-v1 to said central-processing-unit 600-CPU in less than 10 (ten) microseconds from said initiation.
FIG. 15A illustrates one embodiment of a system 700 configured to control random access memory in a shared memory pool 512. There is a first server 618a, which includes a first memory module 540-m1, a first data interface 523-1, and a second compute element 700-c2. The first memory module 540-m1 includes various data sets which may be requested by a first compute element 600-c1 located on a second server 618b. The first compute element 600-c1 may request access 600-req2 to a data set 703-D1 over a communication network 702 that is in communicative contact with the first server 618a, in which the request is sent to the first data interface 523-1. Simultaneously: (i) the first data interface 523-1 performs a first random access read cycle 703-RD-D1 in conjunction with the first memory module 540-m1 to retrieve the requested first data set 703-D1, and (ii) the access controller 701 determines if the first compute element 600-c1 is authorized to have access to the requested data set 703-D1, such that the determination does not delay the first random access read cycle 703-RD-D1. If the first compute element 600-c1 is authorized to access the first data set 703-D1, then the first server 618b will provide the requested data set 703-D1 to the first compute element 600-c1. If the first compute element 600-c1 is not authorized to receive the first data set 703-D1, then the access controller 701 will prevent delivery of the first data set 703-D1.
In an alternative embodiment illustrated in FIG. 15A, a second compute element 700-c2 is co-located on the first server 618a with the first data interface 523-1 and the first memory module 540-m1. The second compute element 700-c2 is in communicative contact with the first data interface 523-1 via a local data bus 704, which could be, for example, a PCIE bus or Infiniband. The second compute element 700-c2 requests 700-req a second data set 703-D2 from the first memory module 540-m1. The processing of the second request 700-req is similar to the processing of the request 600-req2 from the first compute element 600-c1. This second request 700-req is sent to the first data interface 523-1. Simultaneously: (i) the access controller 701 determines if the second compute element 700-c2 is authorized to access the second data set 703-D2, while (ii) the first data interface 523-1 in conjunction with the first memory module 540-m1 perform a second random access read cycle 703-RD-D2 resulting in the retrieval of the second data set 703-D2. If the access controller 701 determines that the second compute element 700-c2 is authorized to access the second data set 703-D2, then the second data set 703-D2 is sent to the second compute element 700-c2 over the local data bus 704. If the second compute element 700-c2 is not authorized to access the second data set 703-D2, then the access controller 701 prevents delivery of the second data set 703-D2 to the second compute element 700-c2.
In an alternative embodiment illustrated in FIG. 15A, a system is configured to allow or not allow a compute element to write a data set into the shared memory pool. In one embodiment, a first compute element 600-c1 requests to write a third data set into a third address located within the first memory module 540-m1. This third request is sent from the first compute element 600-c1 over the communication network 702 to the first data interface 523-1, and the third data set is then temporarily stored in buffer 7TB. After the first compute element 600-c1 sends this third request, the first compute element 600-c1 can continue doing other work without waiting for an immediate response to the third request. If the access controller 701 determines that the first compute element 600-c1 is authorized to write the third data set into the third address, then the first data interface 523-1 may copy the third data set into the third address within the first memory module 540-m1. If the first compute element is not authorized to write into the third address, then the access controller 701 will prevent the copying of the third data set into the third address within the first memory module 540-m1.
In an alternative to the alternative embodiment just described, the requesting compute element is not the first compute element 600-c1 but rather the second compute element 700-c2, in which case the third request is conveyed by the local data bus 704, and the rest of the process is essentially as described above, all with the second compute element 700-c2 rather than the first compute element 600-c1.
In the various embodiments illustrated in FIG. 15A, different permutations are possible. For example, if a particular compute element, be it the first 600-c1 or the second 700-c2 or another compute element, makes multiple requests, all of which are rejected by the access controller 701 due to lack of authorization, that compute element may be barred from accessing a particular memory module, or barred even from accessing any data set in the system.
FIG. 15B illustrates one embodiment of a sub-system with an access controller 701 that includes a secured configuration 701-sec which may be updated by a reliable source 701-source. This is a sub-system of the entire system 700. Access controller 701 is implemented as a hardware element having a secured configuration function 701-sec operative to set the access controller into a state in which a particular compute element (600-c1, or 700-c2, or another) is authorized to access some data set located in first memory module 540-m1, but a different compute element (600-c1, or 700-c2, or another) is not authorized to access the same data set. The rules of authorization are located within a secured configuration 701-sec which is part of the access controller 701. These rules are created and controlled by a reliable source 701-source that is not related to any of the particular compute elements. The lack of relationship to the compute elements means that the compute elements cannot create, delete, or alter any access rule or state of access, thereby assuring that no compute element can gain access to a data set to which it is not authorized. FIG. 15B shows a particular embodiment in which the reliable source 701-source is located apart from the access controller, and thereby controls the secured configuration 701-sec remotely. In alternative embodiments, the reliable source 701-source may be located within the access controller 701, but in all cases the reliable source 701-source lacks a relationship to the compute elements.
The communicative connection between the reliable source 701-source and the secured configuration 701-sec is any kind of communication link, while encryption and/or authentication techniques are employed in order to facilitate said secure configuration.
FIG. 15C illustrates one alternative embodiment of a system operative to control random memory access in a shared memory pool. Many of the elements described with respect to FIGS. 15A and 15B. appear here also, but in a slightly different configuration. There is a motherboard 700-MB which includes the second compute element 700-c2, the first data interface 523-1, and the shared memory pool 512, but these structural elements do not all reside on a single module within the motherboard 700-MB. The first memory module 540-m1, and the first data interface 523-1, including the access controller 701, are co-located on one module 700-module which is placed on the motherboard 700-MB. The second compute element 700-c2, which still makes requests 700-req over the local data bus 704, is not co-located on module 700-module, but rather is in contact with module 700-module through a first connection 700-con-1 which is connected to a first slot 700-SL in the motherboard. In FIG. 15C, the first compute element 600-c1 still makes requests 600-req2 over a communication network 702 that is connected to the motherboard 700-MB through a second connection 700-con-2, which might be, for example, and Ethernet connector. In the particular embodiment illustrated in FIG. 15C, there is a reliable source 701-source that controls authorizations of compute elements to access data sets, such reliable source 701-source is located outside the motherboard 700-MB, and the particular connection between the reliable source 701-source and the motherboard 700-MB is the communication network 702 which is shared with the first compute element 600-c1. This is only one possible embodiment, and in other embodiments, the reliable source 701-source does not share the communication network 702 with the first compute element 600-c1, but rather has its own communication connection with the motherboard 700-MB. In some embodiments, the length of the local data bus 704 is on the order of a few centimeters, whereas the length of the communication network 702 is on the order of a few meters to tens of meters.
One embodiment is a system 700 operative to control random memory access in a shared memory pool, including a first data interface 523-1 associated with a first memory module 540-m1 belonging to a shared memory pool 512, an access controller 701 associated with the first data interface 523-1 and with the first memory module 540-m1, and a first compute element 600-c1 connected with the first data interface 523-1 via a communication network 702, whereas the first memory module 540-m1 is an external memory element relative to the first compute element 600-c1. That is to say, there is not a direct connection between the first compute element 600-c1 and the first memory module 540-m1 (e.g. the two are placed on different servers). Further, the first data interface 523-1 is configured to receive, via the communication network 702, a new request 600-req2 from the first compute element 600-c1 to access a first set of data 703-D1 currently stored in the first memory module 540-m1. Further, the first data interface 523-1 is further configured to retrieve the first set of data 703-D1, as a response to the new request 600-req2, by performing at least a first random access read cycle 703-RD-D1 in conjunction with the first memory module 540-m1. Further, the access controller 701 is configured to prevent delivery of said first set of data 703-D1 to said first compute element 600-c1 when determining that said first compute element is not authorized to access the first set of data, but such that the retrieval is allowed to start anyway, thereby preventing the determination from delaying the retrieval when the first compute element is authorized to access the first set of data.
In one embodiment, said retrieval is relatively a low latency process due to the read cycle 703-RD-D1 being a random access read cycle that does not require sequential access. In one embodiment, the retrieval, which is a relatively low latency process, comprises the random access read cycle 703-RD-D1, and the retrieval is therefore executed entirely over a period of between 10 nanoseconds and 1000 nanoseconds, thereby making said retrieval highly sensitive to even relatively short delays of between 10 nanoseconds and 1000 nanoseconds associated with said determination, thereby requiring said retrieval to start regardless of said determination process.
In one alternative embodiment to the system 700 operative to control random memory access in a shared memory pool 512, the system includes further a second compute element 700-c2 associated with the first memory module 540-m1, whereas the first memory module is a local memory element relative to the second compute element. The system 700 includes further a local data bus 704 operative to communicatively connect the second compute element 700-c2 with the first data interface 523-1. Further, the first data interface 523-1 is configured to receive, via the local data bus 704, a second request 700-req from the second compute element 700-c2 to access a second set of data 703-D2 currently stored in the first memory module 540-m1. Further, the first data interface 523-1 is configured to retrieve the second set of data 703-D2, as a response to said second request 700-req, by performing at least a second random access read cycle 703-RD-D2 in conjunction with the first memory module 540-m1. Further, the access controller 701 is configured to prevent delivery of the second set of data 703-D2 to the second compute element 700-c2 after determining that the second compute element in not authorized to access the second set of data.
In one possible configuration of the alternative embodiment described above, further the access controller 701 is implemented as a hardware element having a secured configuration function 701-sec operative to set the access controller into a state in which the second compute element 700-c2 is not authorized to access the second data set 703-D2. Further, the secured configuration function 701-sec is controllable only by a reliable source 701-source that is not related to the second compute element 700-c2, thereby preventing the second compute element 700-c2 from altering the state, thereby assuring that the second compute element does not gain access to the second data set 703-D2.
In a second possible configuration of the alternative embodiment described above, further the second compute element 700-c2, the first data interface 523-1, the access controller 701, and the first memory module 540-m1 are placed inside a first server 618a. Further, the first compute element 600-c1 is placed inside a second server 618b, which is communicatively connected with the first server 618a via the communication network 702.
In one variation of the second possible configuration described above, further the first data interface 523-1, the access controller 701, and the first memory module 540-m1 are packed as a first module 700-module inside the first server 618a 
In one option of the variation described above, further the second compute element 700-c2 is placed on a first motherboard 700-MB. Further, the first module 700-module has a form factor of a card, and is connected to the first motherboard 700-MB via a first slot 700-SL in the first motherboard.
In a second alternative embodiment to the system 700 operative to control random memory access in a shared memory pool 512, further the retrieval is performed prior to the prevention, such that the retrieval is performed simultaneously with the determination, thereby avoiding delays in the retrieval. Further, the prevention is achieved by blocking the first set of data 703-D1 retrieved from reaching the first compute element 600-c1.
In a third alternative embodiment to the system 700 operative to control random memory access in a shared memory pool 512, further the prevention is achieved by interfering with the retrieval after the determination, thereby causing the retrieval to fail.
In a fourth alternative embodiment to the system 700 operative to control random memory access in a shared memory pool 512, further the shared memory pool is a key-value store, the first data set 703-D1 is a first value 618-v1 (FIG. 13A) associated with a first key 618-k1, the first key 618-k1 is conveyed by said new request 600-req2, and the retrieval comprises finding the first value 618-v1 in the first memory module 540-m1 using the first key 618-k1 conveyed, prior to the performing of the first random access read cycle 703-RD-D1.
In one possible configuration of the fourth alternative embodiment described above, further the authorization is managed by a reliable source 701-source at the key-value store level, such that the first compute element 600-c1 is authorized to access a first plurality of values associated respectively with a first plurality of keys, and such that the first compute element is not authorized to access a second plurality of values associated respectively with a second plurality of keys, wherein the first value 618-v1 belongs to said second plurality of values.
In a fifth alternative embodiment to the system 700 operative to control random memory access in a shared memory pool 512, further the first memory module 540-m1 is based on a random-access-memory (RAM), the first data set 703-D1 is located in a first address associated with the random-access-memory, and the first address is conveyed by the new request 600-req2.
In one possible configuration of the fifth alternative embodiment described above, further the authorization is managed by a reliable source 701-source at the random-access-memory address level, such that the first compute element 600-c1 is authorized to access a first range of addresses, and such that the first compute element is not authorized to access a second range of addresses, wherein the first data set 703-D1 has an address that is within the second range of addresses. In some embodiments, the random-access-memory (RAM) is DRAM. In some embodiments, random-access-memory (RAM), is Flash memory.
One embodiment is a system 700 operative to control random memory access in a shared memory pool 512, including a first data interface 523-1 associated with a first memory module 540-m1 belonging to a shared memory pool 512, an access controller 701 and a temporary write buffer 7TB associated with the first data interface 523-1 and the first memory module 540-m1, and a first compute element 600-c1 connected with the first data interface 523-1 via a communication network 702 whereas the first memory module 540-m1 is a memory element that is external relative to the first compute element. Further, the first data interface 523-1 is configured to receive, via the communication network 702, a third request from the first compute element 600-c1 to perform a random write cycle for a third set of data into a third address within the first memory module 540-m1. Further, the first data interface 523-1 is configured to temporarily store the third set of data and third address in the temporary write buffer 7 TB, as a response to the third request, thereby allowing the first compute element 600-c1 to assume that the third set of data is now successfully stored in the first memory module 540-m1. Further, the first data interface 523-1 is configured to copy the third set of data from the temporary write buffer 7 TB into the third address within the first memory module 540-m1, using at least one random access write cycle, but only after said access controller 701 determining that the first compute element 600-c1 is authorized to write into the third address.
One embodiment is a system 700-module operative to control data access in a shared memory pool 512, including a first memory module 540-m1 belonging to a shared memory pool 512, configured to store a first 703-D1 and a second 703-D2 set of data. The system includes also a first data interface 523-1 associated with the first memory module 540-m1, and having access to (i) a first connection 700-con-1 with a local data bus 704 of a second system 700-MB, and to (ii) a second connection 700-con-2 with a communication network 702. The system includes also an access controller 701 associated with the first data interface 523-1 and the first memory module 540-m1. Further, the first data interface 523-1 is configured to facilitate a first memory transaction associated with the first set of data 703-D1, via the communication network 702, between a first compute element 600-c1 and the first memory module 540-m1. Further, the first data interface 523-1 is configured to facilitate a second memory transaction associated with the second set of data 703-D2, via the local data bus 704, between a second compute element 700-c2 belonging to the second system 700-MB and the first memory module 540-m1. Further, the access controller 701 is configured to prevent the second compute element 700-c2 from performing a third memory transaction via the local data bus 704 in conjunction with the first set of data 703-D1, by causing the first data interface 523-1 to not facilitate the third memory transaction.
In an alternative embodiment to the system 700-module operative to control data access in a shared memory pool 512, further the second system 700-MB is a motherboard having a first slot 700-SL, and the first connection 700-con-1 is a connector operative to connect with said first slot.
In one possible configuration of the alternative embodiment just described, further the first local bus 704 is selected from a group of interconnects consisting of: (i) peripheral-component-interconnect-express (PCIE) computer expansion bus, (ii) Ethernet, and (iii) Infiniband.
In a second alternative embodiment to the system 700-module operative to control data access in a shared memory pool 512, further the communication network 702 is based on Ethernet, and the second connection 700-con-2 in an Ethernet connector. In one embodiment, system 700-module is a network interface card (NIC).
FIG. 16A illustrates one embodiment of a method for determining authorization to retrieve a first value 681-v1 in a key-value store 621 while preserving low latency associated with random-access retrieval. In step 1071, a first data interface 523-1 receives a new request 600-req2 from a first compute element 600-c1 to access a first value 618-v1 (FIG. 13A) currently stored in a first memory module 540-m1 associated with the first data interface, wherein the first memory module belongs to a key-value store 621 (FIG. 13A), and the first value is associated with a first key 618-k1 that is conveyed by the new request 600-req2. In step 1072, a determination process is started in which an access controller 701 associated with the first data interface 523-1 determines whether or not the first compute element 600-c1 is authorized to access the first value. In step 1073, using the first key 618-k1, the first data interface 523-1 finds in the memory module 540-m1 a first location that stores the first value 618-v1, and this finding occurs simultaneously with the determination process described in step 1072. In step 1074, the first data interface 523-1 performs a first random access read cycle 703-RD-D1 in conjunction with the first memory module 540-m1, thereby retrieving the first value 618-v1, and this cycle is performed simultaneously with the determination process described in step 1072. In step 1075, the access controller 701 finishes the determination process. In step 1076, when the determination process results in a conclusion that the first compute element 600-c1 is not authorized to access the first value 618-v1, the access controller 701 prevents delivery of the first value 618-v1 retrieved for the first compute element 600-c1. In some embodiments, the finding in step 1073 and the performing in step 1074 are associated with random-access actions done in conjunction with the first memory module 540-m1, and the result is that the retrieval has a low latency, which means that the simultaneity of steps 1073 and 1074 with the determination process facilitates a preservation of such low latency.
In an alternative embodiment to the method just described for determining authorization to retrieve a first value 618-v1 in a key-value store 621 while preserving low latency associated with random-access retrieval, further when the determination process results in a conclusion that the first compute element 600-c1 is authorized to access said value 618-v1, the access controller 701 allows delivery of the retrieved value 618-v1 to the first compute element 600-c1.
FIG. 16B illustrates one embodiment of a method for determining authorization to retrieve a first value 618-v1 in a key-value store 621 while preserving low latency associated with random-access retrieval. In step 1081, a first data interface 523-1 receives a new request 600-req2 from a first compute element 600-c1 to access a first value 618-v1 (FIG. 13A) currently stored in a first memory module 540-m1 associated with the first data interface, wherein the first memory module belongs to a key-value store 621 (FIG. 13A), and the first value is associated with a first key 618-k1 that is conveyed by the new request 600-req2. In step 1082, a determination process is started in which an access controller 701 associated with the first data interface 523-1 determines whether or not the first compute element 600-c1 is authorized to access the first value. In step 1083, using a the first key 618-k1, the first data interface 523-1 starts a retrieval process that includes (i) finding in the first memory module 540-m1 a first location that stores the first value 618-v1, and (ii) performing a first random access read cycle 703-RD-D1 at the first location to obtain the first value 618-v1, such that the retrieval process occur simultaneously with the determination process performed by the access controller 701. In step 1084, the access controller finishes the determination process. In step 1085, when the determination process results in a conclusion that the first compute element 600-c1 is not authorized to access the first value 618-v1, the access controller 701 interferes with the retrieval process, thereby causing the retrieval process to fail, thereby preventing delivery of the first value 618-v1 to the first compute element 600-c1.
FIG. 17A illustrates one embodiment of a system 720 operative to distributively process a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 stored on a plurality of memory modules 540-m1, 540-m2, 540-mk In this system 720, a plurality of compute elements 700-c1, 700-c2, 700-cn send requests for data to one or more data interfaces 523-1, 523-2, 523-k. Data is held in data sets which are located in memory modules 540-m1, 540-m2, 540-mk, which together comprise a shared memory pool 512. Each data interface is associated with one or more memory modules 540-m1, 540-m2, 540-mk. As an example, data interface 523-1 is associated with memory module 540-m1. In the embodiment shown in FIG. 17A, each data registry 723-R1, 723-R2, 723-Rk is associated with one of the data interfaces. Each memory module includes one or more data sets. In the embodiment shown, memory module 540-m1 includes data sets 712-D1, 712-D2, memory module 540-m2 includes data sets 712-D3, 712-D4, and memory module 540-mk includes data sets 712-D5, 712-D6. It is understood that a memory module may include one, or two, or any other number of data sets. It is understood that the shared memory pool 512 may include two, three, or any other plurality number of memory modules. It is understood that the system may include one, two, or any other number of data interfaces, and one, two, or any other number of compute elements. Various functions of each data interface may be: to know the location of each data set included within an associated memory module, to receive requests for data from compute elements, to extract from the associated memory modules data sets, to send as responses to the compute elements the data sets, and to keep track of which data sets have already been served to the compute elements. Within each data registry is an internal registry which facilitates identification of which data sets have not yet been served, facilitates keeping track of data sets which have been served, and may facilitate the ordering by which data sets that have not yet been served to the compute elements will be served. In FIG. 17A, data interface 523-1 includes internal registry 723-R1, data interface 523-2 including internal registry 723-R2, and data interface 523-k includes internal registry 523-Rk.
In an embodiment alternative to the embodiment shown in FIG. 17A, the internal registries 723-R1, 723-R2, and 723-Rk, are not part of data interfaces. Rather, there is a separate module between the data interfaces 523-1, 523-2, 523-k, and the memory modules 540-m1, 540-m2, 540-mk. This separate module includes one or more internal registries, and the functions of the internal registries, as described above, are implemented in this separate module rather than in the data interfaces illustrated in FIG. 17A.
FIG. 17B illustrates one embodiment of a system in which a plurality of compute elements 700-c1, 700-c2 send data requests 7DR1, 7DR2 to a single data interface 523-1 which then accesses multiple data sets 712-D1, 712-D2 stored in a single memory module 540-m1. In various embodiments, any number of compute elements may send data requests to any number of data interfaces. In the particular embodiment illustrated in FIG. 17B, a plurality of compute elements 700-c1, 700-c2 send their requests to a single data interface 523-1. It is understood that three or any higher number of compute elements may send their requests to single data interface 523-1. FIG. 17B shows only one memory module 540-m1 associated with data interface 523-1, but two or any other number of memory modules may be associated with data interface 523-1. FIG. 17B shows two data sets 712-D1, 712-D2 included within memory module 540-m1, but there may be three or any other higher number of included data sets. FIG. 17B shows two data requests 7DR1, 7DR2, but there may be three or any other number of data requests send by the compute elements.
FIG. 17C illustrates one embodiment of a system in which a single data interface 523-1 extracts from a single memory module 540-m1 some data sets and sends those data sets as multiple responses 7SR1, 7SR2 to the correct compute element. In this sense, a “correct” compute element means that the compute element which requested data set receives a data set selected for it by the data interface. FIG. 17C is correlative to FIG. 17B. After data interface 523-1 has received the data requests, the data interface 523-1 sends 7SR1 the first data set 712-D1, as a response to request 7DR1, to compute element 700-c1, and the data interface 523-1 sends 7SR2 the second data set 712-D2, as a response to request 7DR2, to compute element 700-c2. It is noted that data interface 523-1 sends data set 712-D2 as a response to request 7DR2 only after concluding, based on sending history as recorded in 723-R1, that data set 712-D2 was not served before.
FIG. 17D illustrates one embodiment of the system in which a single compute element 700-c1 sends a plurality of data requests 7DR1, 7DR3 to a plurality of data interfaces 523-1, 523-2 in which each data interface then accesses data sets stored in an associated memory module. Compute element 700-c1 sends data request 7DR1 to data interface 523-1, which then accesses associated memory module 540-m1 containing data sets 712-D1 and 712-D2. Compute element 700-c1 also sends data request 7DR3 to data interface 523-2, which then accesses associated memory module 540-m2 containing data sets 712-D3 and 712-D4. These two requests 7DR1 and 7DR3 may be sent essentially simultaneously, or with a time lag between the earlier and the later requests. It is understood that compute element 700-c1 may send data requests to three or even more data interfaces, although FIG. 17D shows only two data requests. It is understood that either or both of the data interfaces may have one, two, or more associated memory modules, although FIG. 17D shows only one memory module for each data interface. It is understood that any memory module may have more than two data sets, although FIG. 17D shows exactly two data sets per memory module.
FIG. 17E illustrates one embodiment of the system in which a single compute element 700-c1 receives responses to data requests that the compute element 700-c1 sent to a plurality of data interfaces 523-1, 523-2, in which each data interface accesses an associated memory module and sends the accessed data to the compute element 700-c1. FIG. 17E is correlative to FIG. 17D. Data interface 523-1, as a response to request 7DR1, selects data set 712-D1 since it was not served yet, extracts data set 712-D1 from memory module 540-m1, and serves 7SR1 data set 712-D1 to compute element 700-c1. Data interface 523-2, as a response to request 7DR3, selects data set 712-D3 since it was not served yet, extracts data set 712-D3 from memory module 540-m2, and serves 7SR3 data set 712-D3 to compute element 700-c1. The two responses 7DR1 and 7DR2 may be sent essentially simultaneously, or with a time lag between the earlier and the later. It is noted that data interface 523-2 sends data set 712-D3 as a response to request 7DR3 only after concluding, based on sending history as recorded in 723-R2, that data set 712-D3 was not served before. After serving data set 712-D3, data interface 523-2 may record that fact in 723-R2, and therefore may guarantee that data set 712-D3 is not served again as a result of future requests made by any of the compute elements.
One embodiment is a system 720 that is operative to distributively process a plurality of data sets stored on a plurality of memory modules. One particular form of such embodiment includes a plurality of compute elements 700-c1, 700-c2, 700-cn, a shared memory pool 512 with a plurality of memory modules 540-m1, 540-m2, 540-mk configured to distributively store a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6, and a plurality of data interfaces 523-1, 523-2, 523-k associated respectively with the plurality of memory modules 540-m1, 540-m2, 540-mk. Further, each of the data interfaces is configured to:
(i) receive data requests 7DR1, 7DR2 from any one of the plurality of compute elements, such as 7DR1 from 700-c1, or 7DR2 from 700-c2;
(ii) identify from the data sets 712-D1, 712-D2 of the memory module 540-m1 the data sets 712-D1, 712-D2 that were not served yet;
(iii) serve 7SR1, 7SR2, as replies to the data requests 7DR1, 7DR2, respectively, the data sets identified 712-D1, 712-D2, respectively; and
(iv) keep track of the data sets already served, such that, as an example, after responding with 712-D1 to data request 7DR1, data interface 523-1 keeps a record of the fact that 712-D1 was just served, and therefore data interface 523-1 knows not to respond again with 712-D1 to another data request such as 7DR2, but rather to respond with 712-D2 to data request 7DR2, since 712-D2 has not yet been served.

Further, each of the plurality of compute elements is configured to:

(i) send some of the data requests 7DR1, 7DR3 to at least some of the plurality of data interfaces 523-1, 523-2 respectively;

(ii) receive respectively some of the replies 7SR1, 7SR3 comprising some of the data sets 712-D1, 712-D3 respectively; and

(iii) process the data sets received,

Further, the compute elements continue to send data requests, receive replies, and process data, until a first condition is met. For example, one condition might be that all of the data sets that are part of the data corpus are served and processed.

In one alternative embodiment to the system just described, further the data requests 7DR1, 7DR2, 7DR3 do not specify certain which of the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 should be served to the compute elements 700-c1, 700-c2. Rather, the identification and the keeping track constitute the only way by which the plurality of data interfaces 523-1, 523-2, 523-k know which one of the plurality of data sets is to be specifically served to the specific compute element making the data request, and thereby identification and keeping track constitute the only way by which the system 720 insures that none of the data sets is served more than once. As a non-limiting example, when sending data request 7DR1, compute element 700-c1 does not specify in the request that data set 712-D1 is to be served as a response.
The decision to send data set 712-D1 as a response to data request 7DR1 is made independently by data interface 523-1 based on records kept indicating that data set 712-D1 was not yet served. The records may be kept within the internal register 723-R1 of data interface 523-1.
In one possible configuration of the alternative embodiment just descried, further the plurality of compute elements 700-c1, 700-c2, 700-cn comprises a first compute element 700-c1 and a second compute element 700-c2, the plurality of data interfaces 523-1, 523-2, 523-k comprises a first data interface 523-1 including a first internal registry 723-R1 that is configured to facilitate the identification and the keeping track, and the plurality of memory modules 540-m1, 540-m2, 540-mk comprises a first memory module 540-m1 associated with the first data interface 523-1 and configured to store a first data set 712-D1 and a second data set 712-D2. Further, the first compute element 700-c1 is configured to send a first data request 7DR1 to the first data interface 523-1, and the first data interface is configured to (i) conclude, according to the first internal registry 723-R1, that the first data set 712-D1 is next for processing from the ones of the data sets 712-D1, 712-D2 stored in the first memory module 540-m1, (ii) extract the first data set 712-D1 from the first memory module 540-m1, (iii) serve 7SR1 the first data set 712-D1 extracted to the first compute element 700-c1, and (iv) update the first internal registry 723-R1 to reflect said serving of the first data set. Further, the second compute element 700-c2 is configured to send a second data request 7DR2 to the first data interface 523-1, and the first data interface is configured to (i) conclude, according to the first internal registry 723-R1, that the second data set 712-D2 is next for processing from the ones of the data sets 712-D1, 712-D2 stored in the first memory module 540-m1, (ii) extract the second data set 712-D2 from the first memory module 540-m1, (iii) serve the second data set 712-D2 extracted to the second compute element 700-c2, and (iv) update the first internal registry 723-R1 to reflect said serving of the second data set.
In one possible variation of the configuration just described, further the plurality of data interfaces 523-1, 523-2, 523-k comprises a second data interface 523-2 including a second internal registry 723-R2 that is configured to facilitate the identification and the keeping track, and the plurality of memory modules 540-m1, 540-m2, 540-mk comprises a second memory module 540-m2 associated with said second data interface 523-2 and configured to store a third data set 712-D3 and a fourth data set 712-D4. Further, the first compute element 700-c1 is configured to send a third data request 7RD3 to the second data interface 523-2, and the second data interface is configured to (i) conclude, according to the second internal registry 723-R2, that the third data set 712-D3 is next for processing from the ones of the data sets 712-D3, 712-D4 stored in the second memory module 540-m2, (ii) extract the third data set 712-D3 from the second memory module 540-m2, (iii) serve the third data set 712-D3 extracted to the first compute element 700-c1, and (iv) update the second internal registry 723-R2 to reflect said serving of the third data set. Further, the second compute element 700-c2 is configured to send a fourth of said data requests to the second data interface 523-2, and the second data interface is configured to (i) conclude, according to the second internal registry 723-R2, that the fourth data set 712-D4 is next for processing from the ones of the data sets 712-D3, 712-D4 stored in the second memory module 540-m2, (iii) extract the fourth data set 712-D4 from the second memory module 540-m2, (iii) serve the fourth data set 712-D4 extracted to the second compute element 700-c2, and (iv) update the second internal registry 723-R2 to reflect said serving of the fourth data set.
In a second alternative embodiment to the system described to be operative to distributively process a plurality of data sets stored on a plurality of memory modules, further the plurality of compute elements 700-c1, 700-c2, 700-cn are configured to execute distributively a first task associated with the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 by performing the processing of the data sets received.
In one possible configuration of the second alternative embodiment just described, further the execution of the first task can be done in any order of the processing of plurality of data sets, such that any one of the plurality of data sets can be processed before or after any other of the plurality of data sets. In other words, there is flexibility in the order in which data sets may be processed.
In one possible variation of the configuration just described, further the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 constitute a first data corpus, and the first task is selected from a group consisting of: (i) counting number of occurrences of specific items in the first data corpus, (ii) determining size of the data corpus, (iii) calculating a mathematical property for each of the data sets, and (iv) running a mathematical filtering process on each of the data sets.
In a third alternative embodiment to the system described to be operative to distributively process a plurality of data sets stored on a plurality of memory modules, further each of the compute elements 700-c1, 700-c2, 700-cn is configured, per each of the sending of one of the data requests made by such compute element, to select one of the plurality of data interfaces as a target of receiving such data request, wherein the selection is done using a first technique. As a non-limiting example, compute element 700-c1 chooses to send data request 7DR1 to data interface 523-1, and then chooses to send data request 7DR3 to data interface 523-2, but compute element 700-c1 could have, instead, chosen to send data request 7DR3 to data interface 523-k, and in that event compute element 700-c1 would have received a different data set, such as data set 712-D5, as a response to data request 7DR3.
In one possible configuration of the third alternative embodiment just described, further the first technique is round robin selection.
In one possible configuration of the third alternative embodiment just described, further the first technique is pseudo-random selection.
In one possible configuration of the third alternative embodiment just described, further the selection is unrelated and independent of the identification and the keeping track.
In a fourth alternative embodiment to the system described to be operative to distributively process a plurality of data sets stored on a plurality of memory modules, further the keeping track of the data sets already served facilitates a result in which none of the data sets is served more than once.
In a fifth alternative embodiment to the system described to be operative to distributively process a plurality of data sets stored on a plurality of memory modules, further the first condition is a condition in which the plurality of data sets is served and processed in its entirety.
FIG. 18 illustrates one embodiment of a method for storing and sending data sets in conjunction with a plurality of memory modules. In step 1091, a system is configured in an initial state in which a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 belonging to a first data corpus are stored among a plurality of memory modules 540-m1, 540-m2, 540-mk, and such memory modules are associated, respectively, with a plurality of data interfaces 523-1, 523-2, 523-k, such that each of the plurality of data sets is stored only once in only one of the plurality of memory modules. In step 1092, each of the data interfaces 523-1, 523-2, 523-k, respectively, keeps a record 723-R1, 723-R2, 723-Rk about (i) which of the plurality of data sets are stored in the respective memory modules associated with the various data interfaces and (ii) which of the various data sets were served by the data interface to any one of the compute elements 700-c1, 700-c2, 700-cn. In step 1093, each of the data interfaces, 523-1, 523-2, 523-k, receives data request such as 7DR1, 7DR2, 7DR3, from any one of the plurality of compute elements 700-c1, 700-c2, 700-cn. In step 1094, each of the data interfaces selects and serves, as a response to each of the data requests received by that data interface, one of the data sets, wherein the data set selected is stored in a memory module associated with that data interface, and wherein the data interface knows and guarantees that the data set served as a response was not previously served by the data interface since the start of the initial state. For example, data interface 523-1 might serve, as a response to receiving data request 7DR1, one data set such as 712-D1, where that data set is stored in a memory module 540-m1 associated with data set 523-1, and the selection of that data set 712-D1 is based on the record 723-R1 kept by the data interface 523-1 which indicates that this data set 712-D1 has not been previously sent as a response since the start of the initial state. In some embodiments, eventually all of the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6, are served distributively to the plurality of compute elements 700-c1, 700-c2, 700-cn, thereby allowing the plurality of compute elements to distributively process the entire first data corpus.
In one alternative embodiment to the method just described, further the plurality of data sets is a plurality of values associated with a respective plurality of keys, and the data requests are requests for the values associated with the keys. For example, a plurality of values, 618-v1, 618-v2, 618-v3 (all from FIG. 13A), may be associated respectively with a plurality of keys, e.g. 618-k1, 618-k2, 618-k3 (all from FIG. 13A), and the data requests are requests for the values associated with the keys.
In one possible configuration of the alternative embodiment just described, the plurality of compute elements 700-c1, 700-c2, 700-cn, do not need to keep track of which values have already been served because a record of served values is already kept by each data interface. Therefore, the requests do not need to specify specific keys or values, because the data interfaces already know which keys and values can still be served to the plurality of compute elements.
FIG. 19A illustrates one embodiment of a system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn, accessing a shared memory pool 512. The system 740 includes a first data interface 523-G that is communicatively connected to both the compute elements 700-c1, 700-c2, 700-cn and the shared memory pool 512. The shared memory pool 512 includes a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 which comprise a data corpus related to a particular task to be processed by the compute elements 700-c1, 700-c2, 700-cn. The data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 may be stored in the shared memory pool 512 in any manner, including individually as shown in FIG. 19A, or within various memory modules not shown in FIG. 19A, or in a combination in which some of the various data sets are stored individually while others are stored in memory modules. Upon receiving requests from the compute elements 700-c1, 700-c2, 700-cn for data sets related to a particular task being processed by the compute elements 700-c1, 700-c2, 700-cn, the first data interface 523-G extracts the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 from the shared memory pool 512 and serves them to the compute elements 700-c1, 700-c2, 700-cn. The rate at which the first data interface 523-G extracts and serves data sets to a particular compute element is proportional to the rate at which that compute elements requests to receive data sets, and each compute element may request data sets as the compute element finishes processing of an earlier data set and becomes available to receive and process additional data sets. Thus, the first data interface 523-G, by extracting and serving data sets in response to specific data requests, helps achieve a load balancing of processing among the various compute elements 700-c1, 700-c2, 700-cn, such that there is a balance between available capacity for processing and the receipt of data sets to be processed, such that utilization of system capacity for processing is increased. The first data interface 523-G includes an internal registry 723-RG that is configured to keep track of which of the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 have been extracted from the shared pool 512 and served to the compute elements 700-c1, 700-c2, 700-cn. The first data interface 523-G may extract and serve each of the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 exactly once, thereby insuring that no data set is processed multiple times.
FIG. 19B illustrates one embodiment of a system 740 including multiple compute elements 700-c1, 700-c2 and a first data interface 523-G, in which the system 740 is operative achieve load balancing by serving data sets to the compute elements 700-c1, 700-c2 proportional to the rate at which the compute elements 700-c1, 700-c2 request data sets for processing. As it becomes or is about to become available to process additional data sets, the first compute element 700-c1 sends a first data request 8DR1 to the first data interface 523-G. The first data interface 523-G concludes, based on information in the internal registry 723-RG, that a first data set 712-D1 is the next for processing, so the first data interface 523-G extracts 700-f1 the first data set 712-D1 from the shared memory 512, serves 8SR1 the first data set 712-D1 to the first compute element 700-c1, and updates the internal registry 723-RG to reflect the serving of the first data set. The first compute element 700-c1 continues to perform processing 701-p1 of data sets related to the task, here by processing the first data set received in response 8SR1. As it becomes available or is about to become available to process additional data sets, the second compute element 700-c2 sends a second data request 8DR2 to the first data interface 523-G. The first data interface 523-G concludes, based on information in the internal registry 723-RG, that the first data set has already been served to one of the compute elements but a second data set is the next for processing, so the first data interface 523-G extracts 700-f2 the second data set 712-D2 from the shared memory 512, serves 8SR2 the second data set to the second compute element 700-c2, and updates the internal registry 723-RG to reflect the serving of the second data set. The second compute element 700-c2 continues to perform processing 701-p2 of data sets related to the task, here by processing the second data set received in response 8SR2.
As it becomes available or is about to become available to process additional data sets, the first compute element 700-c1 sends a third data request 8DR3 to the first data interface 523-G. The first data interface 523-G concludes, based on information in the internal registry 723-RG, that the first and second data sets have already been served to the compute elements but a third data set is next for processing, so the first data interface 523-G extracts 700-f3 the third data set 712-D3 from the shared memory 512, serves 8SR3 the third data set to the first compute element 700-c1, and updates the internal registry 723-RG to reflect the serving of the third data set. The first compute element 700-c1 continues to perform processing 701-p3 of data sets related to the task, here by processing the third data set received in response 8SR3.
As it becomes available or is about to become available to process additional data sets, the first compute element 700-c1 sends a fourth data request 8DR4 to the first data interface 523-G. The first data interface 523-G concludes, based on information in the internal registry 723-RG, that the first, second, and third data sets have already been served to the compute elements but a fourth data set is next for processing, so the first data interface 523-G extracts 700-f4 the fourth data set 712-D4 from the shared memory 512, serves 8SR4 the fourth data set to the first compute element 700-c1, and updates the internal registry 723-RG to reflect the serving of the fourth data set. The first compute element 700-c1 continues to perform processing 701-p4 of data sets related to the task, here by processing the third data set received in response 8SR4.
It is understood that in all of the steps described above, the compute elements 700-c1, 700-c2 can process data sets only after they have received such data sets from the first data interface 523-G. The first data interface 523-G, however, has at least two alternative modes for fetching and sending data sets to the compute elements 700-c1, 700-c2. In one mode, the first data interface 523-G fetches a data set only after it has received a data request from one of the compute elements. This mode is reflected in element 700-f3, in which the first data interface 523-G first receives a data request 8DR3 from the first compute element 700-c1, the first data interface 523-G then fetches 700-f3 the third data set, and the first data interface 523-G then serves 8SR3 third data set to the first compute element 700-c1. In a second mode, the first data interface 523-G first fetches the next available data set before the first data interface 523-G has received any data request from any of the compute elements, so the first data interface 523-G is ready to serve the next data set immediately upon receiving the next data request from one of the compute elements 700-c1, 700-c2. This mode is illustrated in 700-f1, in which the first data interface 523-G fetches a first data set prior to receiving the first data request 8DR1 from the first compute element 700-c1, in 700-f2, in which the first data interface 523-G fetches a second data set prior to receiving the second data request 8DR2 from the second compute element 700-c2, and in 700-f4, in which the first data interface 523-G fetches a fourth data set prior to receiving the fourth data request 8DR4 from the first compute element 700-c1. By this second mode, there is no loss of time that might have resulted if the first data interface 523-G were fetching a data set while the requesting compute element was waiting for data.
FIG. 19B illustrates a time line, in which time begins at the top and continues towards the bottom. In one embodiment, over a first period 709-per, the first compute element 700-c1 issues exactly three data requests 8DR1, 8DR3, and 8DR4, receiving respectively responses 8SR1, 8SR3, and 8SR4 which include, respectively, a first data set 712-D1, a third data set 712-D3, and a fourth data set 712-D4, which the first compute element 700-c1 then processes, 701-p1, 701-p3, 701-p4, respectively. The first compute element 700-c1 does not issue additional data requests during the first period 709-per, because the first compute element 700-c1 will not be able to process received data within the time of 709-per. In one embodiment, 8DR3 is issued only after 701-p1 is done or about to be done, and 8DR4 is issued only after 701-p3 is done or about to be done, such that the first compute element 700-c1 issues data requests at a rate that is associated with the processing capabilities or availability of the first compute element 700-c1.
In one embodiment, over the same first period 709-per, the second compute element 700-c2 issues only one data request 8DR2, because the corresponding processing 701-p2 of the corresponding second data set 712-d2 requires long time, and further processing by the second compute element 700-c2 will not fit within the time period of 709-per. In this way, the second compute element 700-c2 issues data requests at a rate that is associated to the processing capabilities or availability of the second compute element 700-c2.
As explained above, each of the first compute element 700-c1 and the first compute element 700-c2 issues data requests in accordance with its processing capabilities or availability within a given time period. It is to be understood that data requests, receiving of data sets, and processing of data sets by the compute elements 700-c1 and 700-c2 are not synchronized, and therefore are unpredictably interleaved. Further, the compute elements 700-c1, 700-c2 are not aware of exactly which data set is received per each data request, but the compute elements 700-c1, 700-c2 do not request specific data sets, do not make the selection of which data sets they will receive, and do not know which data sets have been received from the first data interface 523-G. It is the first data interface 523-G that decides which data sets to serve based on the records kept in the internal registry 723-RG, the data sets selected have never yet been served to the compute element 700-c1, 700-c2, and the data sets are served by the first data interface 523-G in response to specific data requests from the compute elements 700-c1, 700-c2. The keeping of records in the internal registry 723-RG and the selection of data sets to be served based on those records, allows the achievement of load balancing among the various compute elements 700-c1, 700-c2, and this is true whether or not the various compute elements have the same processing capabilities or processing availabilities.
One embodiment is a system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512. One particular form of such embodiment includes a shared memory pool 512 configured to store and serve a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 comprising at least a first data set 712-D1 and a second data set 712-D2; a first data interface 523-G configured to extract and serve any of the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 from the shared memory pool 512, and comprising an internal registry 723-RG configured to keep track of the data sets extracted and served; and a plurality of compute elements 700-c1, 700-c2, 700-cn comprising at least a first compute element 700-c1 and a second compute element 700-c2, wherein the plurality of compute elements 700-c1, 700-c2 are communicatively connected with the first data interface 523-G, and the plurality of compute elements 700-c1, 700-c2 are configured to execute distributively a first task associated with the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6. Further, the first compute element 700-c1 is configured to send a first data request 8DR1 to the first data interface 523-G after deciding that the first compute element is currently available or will be soon available to start or continue contributing to execution of the task (i.e., processing one of the data sets), and the first data interface 523-G is configured to (i) conclude, according to the records kept in the internal registry 723-RG, that the first data set 712-D1 is next for processing, (ii) extract 700-f1 the first data set 712-D1 from the shared memory pool 512, (iii) serve 8SR1 the first data set extracted to the first compute element 700-c1 for performing said contribution 701-p1 (i.e., processing data set 712-D1), and (iv) update the internal registry 723-RG to reflect the serving of the first data set 712-D1 to the first compute element 700-c1. Further, the second compute element 700-c2 is configured to send a second data request 8DR2 to the first data interface 523-G after deciding that the second compute element 700-c2 is currently available or will be soon available to start or continue contributing to execution of the task, and the first data interface 523-G is configured to (i) conclude, according to the internal registry 723-RG reflecting that the first data set 712-D1 has already been served, that the second data set 712-D2 is next for processing, (ii) extract 700-f2 the second data set from the shared memory pool 512, (iii) serve 8SR2 the second data set extracted to the second compute element 700-c2 for performing the contribution 701-p2 (i.e., processing data set 712-D2), and (iv) update the internal registry 723-RG to reflect the serving of the second data set 712-D2 to the second server 700-c2. As herein described, the decisions regarding the availabilities facilitate the load balancing in conjunction with the executing distributively of the first task, all without the plurality of compute elements 700-c1, 700-c2, 700-cn being aware of the order in which the plurality of data sets are extracted and served by the first data interface 523-G.
In one alternative embodiment to the system just described, further the plurality of data sets further comprises at least a third data set 712-D3. Also, the first compute element 700-c1 is further configured to send a next data request 8DR3 to the first data interface 523-G after deciding that the first compute element 700-c1 is currently available or will be soon available to continue contributing to the execution of the task, and the first data interface 523-G is configured to (i) conclude, according to the internal registry 723-RG, that the third data set 712-D3 is next for processing, (ii) extract 700-f3 the third data set from the shared memory pool 512, (iii) serve 8SR3 the third data set extracted to the first compute element 700-c1 for performing the contribution 701-p3 (i.e., processing data set 712-D3), and (iv) update the internal registry 723-RG to reflect the serving of the third data set 712-D3.
In one possible configuration of the first alternative embodiment just described, further the next data request 8DR3 is sent only after the first compute element 700-c1 finishes the processing 701-p1 of the first data set 712-D1, thereby further facilitating said load balancing.
In a second possible configuration of the first alternative embodiment just described, further the first data request 8DR1 and next data request 8DR3 are sent by the first compute element 700-c1 at a rate that corresponds to a rate at which the first compute element 700-c1 is capable of processing 701-p1, 701-p3 the first data set 712-D1 and the third data set 712-D3, thereby further facilitating said load balancing.
In a second alternative embodiment to the above described system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512, further the concluding and the updating guarantee that no data set is served more than once in conjunction with the first task.
In a third alternative embodiment to the above described system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512, further the conclusion by said first data interface 523-G regarding the second data set 712-D2 is made after the second data request 8DR2 has been sent, and as a consequence of the second data request 8DR2 being sent.
In a fourth alternative embodiment to the above described system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512, further the conclusion by the first data interface 523-G regarding the second data set 712-D2 is made as a result of the first data set 712-D1 being served 8SR1, and before the second data request 8DR2 has been sent, such that by the time the second data request 8DR2 has been sent, the conclusion by the first data interface 523-G regarding the second data set 712-D2 has already been made.
In a fifth alternative embodiment to the above described system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512, further the extraction 700-f2 of the second data set 712-D2 from the shared memory pool 512 is done after the second data request 8DR2 has been sent, and as a consequence of the second data request 8DR2 being sent.
In a sixth alternative embodiment to the above described system 740 operative to achieve load balancing among a plurality of compute elements 700-c1, 700-c2, 700-cn accessing a shared memory pool 512, further the extraction 700-f2 of the second data set 712-D2 from the shared memory pool 512 is done as a result of the first data set 712-D1 being served 8SR1, and before the second data request 8DR2 has been sent, such that by the time the second data request 8DR2 has been sent, the second data set 712-D2 is already present in the first data interface 523-G and ready to be served by the first data interface 523-G to a compute element.
FIG. 20 illustrates one embodiment of a method for load balancing a plurality of compute elements accessing a shared memory pool. In step 1101, a system is configured in an initial state in which a plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 belonging to a first data corpus are stored in a shared memory pool 512 associated with a first data interface 523-G, such that each of the plurality of data sets is stored only once. In step 1102, the internal registry 723-RG of a first data interface 523-G keeps a record about which of the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 are stored in the shared memory pool 512 and which of the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 were served by the first data interface 523-G to any one of the plurality of compute elements 700-c1, 700-c2, 700-cn. In step 1103, the first data interface 523-G receives data requests 8DR1, 8DR2, 8DR3, 8DR4 from any of plurality of compute elements 700-c1, 700-c2, 700-cn, in which the rates of request from the various compute elements 700-c1, 700-c2, 700-cn may vary based on factors such as the processing capabilities of the various compute elements 700-c1, 700-c2, 700-cn and the availability of processing time and resources given the various processing activities being executed by each of the compute elements 700-c1, 700-c2, 700-cn. In step 1104, in response to the each of the data requests sent by a compute element and received by the first data interface 523-G, the first data interface 523-G serves one of the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 that is stored in the shared memory pool 512 and that is selected for sending to the compute element making the data request, where the data set is selected and served on the basis of the records kept in the internal registry 723-RG such that the data set served is guaranteed not to have been sent previously by the first data interface 523-G since the start from the initial state of the system 740. For example, the first data interface 523-G may select and serve, based on the records kept in the internal registry 723-RG, the second data set 712-D2 to be sent in response to a second data request 8DR2 from the second compute element 700-c2, wherein the records kept in internal registry 723-RG guarantee that this second data set 712-D2 has not yet been served to any of the compute elements 700-c1, 700-c2, 700-cn. The results are that (i) each data set is served by the first data interface 523-G and processed by one of the compute elements only once; and (ii) each of the plurality of compute elements 700-c1, 700-c2, 700-cn is served data at a rate that is proportional to the rate at which such compute element makes data requests. This proportionality, and the serving of data sets in direct relation to such proportionality, means that load balancing is achieved among the plurality of compute elements 700-c1, 700-c2, 700-cn. 
In one alternative embodiment to the method just described, further the initial state is associated with a first task to be performed by the plurality of compute elements 700-c1, 700-c2, 700-cn in conjunction with the first data corpus, and the initial state is set among the first data interface 523-G and the plurality of compute elements 700-c1, 700-c2, 700-cn in conjunction with the first task, thereby allowing the keeping record, receiving, and serving to commence.
In one possible configuration of the alternative embodiment just described, said record keeping, receiving, and serving allow the plurality of compute elements 700-c1, 700-c2, 700-cn to distributively perform the first task, such that each of the plurality of compute elements 700-c1, 700-c2, 700-cn performs a portion of the first task that is determined by the compute element itself according to the rate at which that compete element is making data requests to the first data interface 523-G.
In one possible variation of the configuration just described, the rate at which each compute element makes data requests is determined by the compute element itself according to the present load on the compute element or the availability of computational capability of the compute element.
In one option of the variation just described, the data requests 8DR1, 8DR2, 8DR3, 8DR4 do not specify specific identities of the data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 to be served, such that the specific identities of the data sets served are determined solely by the first data interface 523-G according to the records kept by the internal registry 723-RG, thereby allowing the plurality of compute elements 700-c1, 700-c2, 700-cn to perform the first task asynchronously, thereby allowing the plurality of compute elements 700-c1, 700-c2, 700-cn to achieve load balancing efficiently.
In a second possible configuration of the alternative embodiment described above, the receiving of data requests and the serving of data sets in response to the data requests, end when the entire first data corpus has been served to the plurality of compute element 700-c1, 700-c2, 700-cn. 
In a possible variation of the second configuration just described, the execution of the first task is achieved after the entire data corpus has been served to the plurality of compute elements 700-c1, 700-c2, 700-cn, and after each of the compute elements has processed all of the data sets that were served to that compute element by the first data interface 523-G.
In a third possible configuration of the alternative embodiment described above, further the first data interface 523-G performs on the plurality of data sets 712-D1, 712-D2, 712-D3, 712-D4, 712-D5, 712-D6 a pre-processing activity associated with the first task, after the extracting 700-f1, 700-f2, 700-f3, 700-f4 of the data sets and prior to the serving 8SR1, 8SR2, 8SR3, 8SR4 of the data sets.
FIG. 21A illustrates one embodiment of a system 740 operative to achieve data resiliency in a shared memory pool 512. The system 740 includes multiple compute elements 700-c1, 700-c2, 700-cn, that execute various functions such as requesting data, receiving data, streaming request to write to memory, and processing data. The system 740 includes also multiple erasure-encoding interfaces 741-1, 741-2, 741-m, that execute various functions such as receiving data requests from compute elements, sending secondary data requests to data interfaces, receiving data fragments from data interfaces, reconstructing data sets, sending reconstructed data sets to compute elements as responses to requests for data, receiving streamed requests to write to memory, erasure-coding data sets into data fragments, creating multiple sub-streams of data fragments, and sending the sub-streams to memory modules to be added to memory. The system 740 includes also a shared memory pool 512 with multiple memory modules 540-m1, 540-m2, 540-mk, that execute various functions includes storing data sets in the form of data fragments. For example, as shown in FIG. 21A, a first data set 712-D1 has been coded 7code at the top into multiple data fragments 7D1-1, 7D1-2, 7D1-k, in which the various fragments are stored in different memory modules, first data fragment 7D1-1 in first memory module 540-m1, second data fragment 7D1-2 in second memory module 540-m2, and third data fragment 7D1-k in third memory module 540-mk. Similarly, FIG. 21A shows a second data set 712-D2 that has been coded 7code at the bottom into multiple data fragments 7D2-1, 7D2-2, 7D2-k, in which the various fragments are stored in different memory modules, first data fragment 7D2-1 in first memory module 540-m1, second data fragment 7D2-2 in second memory module 540-m2, and third data fragment 7D2-k in third memory module 540-mk. Although only two data sets are shown in FIG. 21A, it is understood that there may be many more data sets in a system. Although each data set is shown in FIG. 21 to be coded into three data fragments, it is understood that any data set may be coded into two, four, or any higher number of data fragments. In the particular embodiment shown in FIG. 21A, there are at least two separate severs, a first server 700-S-1 that includes a first memory module 540-m1 and a first data interface 523-1, and a second server 700-S-2 that includes a first erasure-coding interface 741-1.
It should be understood that there may be any number of servers or other pieces of physical hardware in the system 740, and such servers or hardware may include any combination of the physical elements in the system, provided that the entire system 740 includes all of the compute elements 700-c1, 700-c2, 700-ck, all of the erasure-coding interfaces 741-1, 741-2, 741-k, all of the data interfaces 523-1, 523-2, 523-k, and all of the memory modules 540-m1, 540-m2, 540-mk, plus whatever other hardware elements have been added to the system 740. For example, one system might have a server including all of the memory modules and all of the data interfaces, a separate server including all of the erasure-coding interfaces, and a separate server including all of the compute elements. Or alternatively, there may be two more servers for the compute elements, and/or two or more servers for the erasure-coding interfaces, and/or two or more servers for the data interfaces and memory modules. In alternative embodiments, one or more compute elements may be co-located on a server with one or more erasure-coding interfaces and/or one or more data interfaces and memory modules, provided that all of the compute elements, erasure-coding interfaces, data interfaces, and memory modules are located on some server or other physical hardware.
FIG. 21B illustrates one embodiment of a sub-system with a compute element 700-c1 making a data request 6DR1 to an erasure-encoding interface 741-1 which converts the request to a plurality of secondary data requests 6DR1-a, 6DR1-b, 6DR1-k, and sends such secondary data requests to a plurality of data interfaces 523-1, 523-2, 523-k. As shown, each secondary data request is sent to a separate data interface.
FIG. 21C illustrates one embodiment of a sub-system with the plurality of data interfaces 523-1, 523-2, 523-k using random-access read cycles 6RA1-a, 6RA1-b, 6RA-k, to extract multiple data fragments 7D1-1, 7D1-2, 7D1-k stored in associated memory modules 540-m1, 540-m2, 540-mk In the embodiment illustrated in FIG. 21C, the data fragments are part of a data set 712-D1 not shown in FIG. 21C. In the embodiment illustrated in FIG. 21C, the data fragments are stored in random access memory (RAM), which means that the data interfaces extract and fetch the data fragments very quickly using a random access read cycle or several random access read cycles. In the embodiment shown in FIG. 21C, exactly one data interface is associated with exactly one memory module in order to support simultaneity in accessing the various data fragments 7D1-1, 7D1-2, 7D1-k, but in alternative embodiments the various data interfaces and memory modules may be associated otherwise, provided however that the multiple data fragments 7D1-1, 7D1-2, 7D1-k may be extracted in parallel by a plurality of data interfaces, such that the multiple data fragments 7D1-1, 7D1-2, 7D1-k may be fetched quickly by the various data interface, and possibly during several clock cycles in which the various data interfaces access the various memory modules in parallel using simultaneous random access read cycles. Such simultaneity in random access is critical for achieving low latency that is comparable to latencies associated with randomly accessing uncoded data stored in RAM.
FIG. 21D illustrates one embodiment of a sub-system with the plurality of data interfaces 523-1, 523-2, 523-k, sending, as responses 6SR1-a, 6SR1-b, 6SR1-k to a secondary data requests 6DR1-a, 6DR1-b, 6DR1-k (shown in FIG. 21B), data fragments 7D1-1, 7D1-2, 7D1-k to an erasure-coding interface 741-1 which reconstructs 7rec the original data set 712-D1 from the data fragments and sends such reconstructed data set 712-D1 to a compute element 700-c1 as a response 6SR-1 to that compute element's request for data 6DR-1 (shown in FIG. 21B). The data fragments may be sent serially to the erasure-coding interface 741-1, which might be, for example, 7D1-1, then 7D1-2, then 7D1-k, then 7D2-1 (part of second data set 712-D2 shown in FIG. 21A), then 7D1-2 (part of data set 712-D2 shown in FIG. 21A), then 7D1-k (part of data set 712-D2 shown in FIG. 21A). The data fragments 7D1-1, 7D1-2, 7D1-k may be sent simultaneously to the erasure-coding interface 741-1 using a switching network such as switching network 550 (FIG. 21A), which may be selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network, in order to achieve a low latency that is comparable to latencies associated with randomly accessing uncoded data stored in RAM. The erasure-coding interface 741-1 may reconstruct 7rec the data set 712-D1 even if one of the data fragments 7D1-1, 7D1-2, 7D1-k is either missing or corrupted, and this is one aspect of data resiliency of the overall system 740. In the embodiment shown in FIG. 21D, all of the data interfaces are communicatively connected with a single erasure-coding interface 741-1 which is communicatively connected with exactly one compute element 700-c1, but in alternative embodiments the various data interfaces may be communicatively connected with various erasure-coding interfaces, and the various erasure-coding interfaces may be communicatively connected with various compute elements, through the switching network 550 discussed previously.
FIG. 21E illustrates one embodiment of a sub-system with a compute element 700-c1 streaming 7STR a data set 712-D1 (shown in FIG. 21D) to an erasure-coding interface 741-1 which converts the data set into data fragments 7D1-1, 7D1-2, 7D1-k and streams 7STR1, 7STR2, 7STRk such data fragments to multiple data interfaces 523-1, 523-2, 523-k, which then write 7WR1, 7WR2, 7WRk each data fragment in real-time in the memory modules 540-m1, 540-m2, 540-mk associated with the data interfaces. The physical connection between the compute element 700-c1 and the erasure-coding interface, here in FIG. 21E or in any of the FIG. 21A, 21B, or 21D, may be a peripheral-component-interconnect-express (PCIE) computer expansion bus, an Ethernet connection, an Infiniband connection, or any other physical connection permitting high-speed transfer of data between the two physical elements, such as switching network 550. The coding of the data fragment streams 7STR1, STR2, STRk by the erasure-coding interface 741-1 may be done very quickly, in “real-time”. The data interfaces 523-1, 523-2, 523-k write 7WR1, 7WR2, 7WRk the data fragments 7D1-1, 7D1-2, 7D1-k to the memory modules 540-m1, 540-m2, 540-mk in RAM using fast random access cycles, which means that the writing process is very fast, possibly as fast as a single random access write cycle into a RAM.
One embodiment is a system 740 operative to achieve data resiliency in a shared memory pool 512. One particular form of such embodiment includes a plurality of memory modules 540-m1, 540-m2, 540-mk belonging to a shared memory pool 512 and associated respectively with a plurality of data interfaces 523-1, 523-2, 523-k; a first erasure-coding interface 741-1 communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k; and a first compute element 700-c1 communicatively connected with the first erasure-coding interface 741-1. Further, the plurality of memory modules 540-m1, 540-m2, 540-mk are configured to distributively store a plurality of data sets 712-D1, 712-D2, such that each data set is distributively stored among at least two of the memory modules in a form of a plurality of data fragments coded using a first erasure-coding scheme, and each data fragment is stored on a different one of the at least two memory modules. As an example, a first data set 712-D1 may include first data fragment 7D1-1 stored in first memory module 540-m1, second data fragment 7D1-2 stored in second memory module 540-m2, and third data segment 7D1-k stored in third memory module 540-mk. As another example, as either a substitute for the first data set 712-D1, or in addition to the first data set 712-D1, there may be a second data set 712-D2, including a first data fragment 7D2-1 stored in first memory module 540-m1, a second data fragment 7D2-2 stored in second memory module 540-m2, and a third data segment 7D2-k stored in third memory module 540-mk. Further, the first compute element 700-c1 is configured to send to the first erasure-coding interface 741-1 a request 6DR1 for one of the data sets. For example, the first erasure-encoding interface may request a first data set 712-D1. Further, the first erasure-coding interface 741-1 is configured to (i) convert the request into a first plurality of secondary data requests 6DR1-a, 6DR1-b, 6DR1-k; (ii) send the first plurality of secondary data requests, respectively, into at least a first sub-set of the plurality of data interfaces 523-1, 523-2, 523-k; (iii) receive as responses 6SR1-a, 6SR1-b, 6SR1-k at least a sub-set of the plurality of data fragments 7D1-1, 7D1-2, 7D1-k associated with the one of the data sets 712-D1; (iv) reconstruct 7rec the one of the data sets 712-D1, using the first erasure-coding scheme, from the data fragments received 7D1-1, 7D1-2, 7D1-k; and (v) send the reconstruction to the first compute element 700-c1 as a response 6SR1 to the request 6DR1 made. Further, each of the plurality of data interfaces, that is, each of 523-1, 523-2, 523-k, is configured to (i) receive, from the first erasure-coding interface 741-1, one of the plurality of secondary data requests (such as, for example secondary data request 6DR1-a received at first date interface 523-1); (ii) extract, from the respective memory module (such as, for example, from first memory module 540-m1 associated with first data interface 523-1), using a random-access read cycle 6RA1-a, one of the data fragments 7D1-1 associated with the one secondary data request; and (iii) send 6SR1-a the data fragment 7D1-1 extracted to the first erasure-coding interface 741-1 as part of the responses received by the first erasure-coding interface 741-1.
In a first alternative embodiment to the system just described, further one of the plurality of memory modules 540-m1 and its associated data interface 523-1 are located in a first server 700-S-1. Further, the first erasure-coding interface 741, the first compute element 700-c1, others of the plurality of memory modules 540-m2, 540-mk, and others of the associated data interfaces 523-2, 523-k, are all located outside the first server 700-S-1. The ultimate result is that, due to the uses of the first erasure-coding interface 741-1 and the first erasure-coding scheme, the system 740 is a distributed system that is configured to endure any failure in the first server 700-S-1, and further that the reconstruction 7rec is unaffected by the possible failure in the first server 700-S-1.
In one possible configuration of the first alternative embodiment just described, the system 740 includes also additional erasure-coding interfaces 741-2, 741-m, each configured to perform all tasks associated with the first erasure-coding interface 741-1, such that any failure of the first erasure-coding interface 741-1 still allows the system 740 to perform the reconstruction 7rec using at least one of the additional erasure-coding interfaces (such as the second erasure-coding interface 741-2) instead of the failed first erasure-coding interface 741-1.
In one possible variation of the configuration just described, further the first erasure-coding interface 741-1 is located in a second server 700-S-2, while the additional erasure-coding interfaces 714-2, 741-m, the first compute element 700-c1, the others of the plurality of memory modules 540-m2, 540-mk, and the associated data interfaces 523-2, 523-k, are all located outside said second server 700-S-2. The result is that the system 740 is further distributed, and is configured to endure any failure in the second server 700-S-2, such that the reconstruction 7rec would still be possible even after a failure in the second server 700-S-2.
In a second alternative embodiment to the above-described system 740 operative to achieve data resiliency in a shared memory pool, the system 740 further includes additional erasure-coding interfaces 741-2, 741-m, each of which is configured to perform all tasks associated with the first erasure-coding interface 741-1. Further, the system 740 also includes additional compute elements 700-c2, 700-cn, each of which is configured to associate with at least one of the erasure-coding interfaces (for example, compute element 700-c2 with erasure-coding interface 741-2, and compute element 700-cn with erasure-coding interface 741-m) in conjunction with erasure-coding transactions such as 7rec and alike, associated with the plurality of memory modules 540-m1, 540-m2, 540-mk and the plurality of data fragments 7D1-1, 7D1-2, 7D1-k, 7D2-1, 7D2-2, 7D2-k. As a result of the additions set forth in this second possible alternative, each of the plurality of compute elements, including the first compute element, is configured to receive one of the data sets 712-D1 reconstructed 7rec using at least one of the additional erasure-coding interfaces 741-2, and also the shared memory pool 512 is configured to serve the plurality of data sets 712-D1, 712-D2 to the plurality of compute elements regardless of any failure in one of the memory modules 540-m1, 540-m2, 540-mk. 
In one possible option for the second alternative embodiment just described, each erasure-coding interface 741-2, 741-2, 741-m is associated with one of the compute elements 700-c1, 700-c2, 700-cn. 
In another possible option for the second alternative embodiment just described, each of the compute elements 700-c1, 700-c2, 700-cn can use any one or any combination of the erasure-encoding interfaces 741-2, 741-2, 741-m, thereby creating a resilient matrix of both data and erasure-coding resources, capable of enduring any single failure scenario in the system. In one possible option of this embodiment, the different elements in the resilient matrix are interconnected using a switching network or an interconnect fabric 550.
In one possible configuration of the second alternative embodiment, further the plurality of memory modules 540-m1, 540-m2, 540-mk are based on dynamic-random-access-memory (DRAM), at least 64 (sixty four) memory modules are included in the plurality of memory modules, and the first erasure-coding interface 741-1 together with the additional erasure-coding interfaces 741-2, 741-m are communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k using a switching network 550 selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network. One result of this possible configuration is that a rate at which the data sets 712-D1, 712-D2 are being reconstructed 7rec is at least 400 Giga-bits-per second.
In a third alternative embodiment to the above-described system 740 operative to achieve data resiliency in a shared memory pool, further the plurality of memory modules 540-m1, 540-m2, 540-mk are based on random-access-memory (RAM), and therefore the random-access read cycles 6RA1-a, 6RA1-b, 6RA1-k allow the extraction to proceed at data rates that support the first compute element 700-c1 in receiving said data sets 712-D1, 712-D2, after said reconstruction 7rec, at data rates that are limited only by the ability of the first compute element 700-c1 to communicate.
In one possible configuration of the third alternative embodiment, further the random-access-memory in memory modules 540-m1, 540-m2, 540-mk is a dynamic-random-access-memory (DRAM), and the first erasure-coding interface 741-1 is communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k using a switching network 550 selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network. One result of this possible configuration is that a first period beginning in the sending of the request 6DR1 and ending in the receiving of the response 6SR1 to the request is bounded by 5 (five) microseconds. In one embodiment, said random-access read cycles 6RA1-a, 6RA1-b, 6RA-k are done simultaneously, as facilitated by the plurality of data interfaces 523-1, 523-2, 523-k acting together, thereby facilitating said bound of 5 (five) microseconds.
In a second possible configuration of the third alternative embodiment, further the random-access-memory in memory modules 540-m1, 540-m2, 540-mk is a dynamic-random-access-memory (DRAM), and the first erasure-coding interface 741-1 is communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k using a switching network 550 selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network. One result of this possible configuration is that a rate at which the data sets 712-D2, 712-D2 are being reconstructed is at least 100 Giga-bits-per second.
In a fourth alternative embodiment to the above-described system 740 operative to achieve data resiliency in a shared memory pool, further the one of the data sets 712-D1 is a first value 618-v1 (illustrated in FIGS. 11A and 13A) associated with a first key 618-k1 (illustrated in FIGS. 11A and. 13A), and the first value 618-v1 is stored as one of the pluralities of data fragments 7D1-1, 7D1-2, 7D1-k in the plurality of memory modules 540-m1, 540-m2, 540-mk. Further, the request 6DR1 for one of the data sets 712-D1 is a request for the first value 618-v1, in which the request 6DR1 conveys the first key 618-k1. Further, the first plurality of secondary data requests 6DR1-a, 6DR1-b, 6DR1-k are requests for the one of the pluralities of data fragments 7D1-1, 7D1-2, 7D1-k, in which each of the requests for the one of the pluralities of data fragments conveys the first key 618-k1 or a derivative of the first key 618-k1 to the respective data interface 523-1, 523-2, 523-k. Further, the respective data interface 523-1, 523-2, 523-k is configured to use the first key 618-k1 or a derivative of the first key to determine an address from which to perform said random access read cycles 6RA1-a, 6RA1-b, 6RA1-k. 
One embodiment is a system 740 operative to stream data resiliently into a shared memory pool 512. One particular form of such embodiment includes a plurality of memory modules 540-m1, 540-m2, 540-mk belonging to a shared memory pool 512 and associated respectively with a plurality of data interfaces 523-1, 523-2, 523-k, a first erasure-coding interface 741-1 communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k, and a first compute element 700-c1 communicatively connected with the first erasure-coding interface 741-1. Further, the first compute element 700-c1 is configured to stream 7STR a plurality of data sets 712-D1, 712-D2 into the first erasure-coding interface 741-1. Further, the first erasure-coding interface 741-1 is configured to (i) receive the stream; (ii) convert in real-time each of the plurality of data sets 712-D1, 712-D2 in the stream into a plurality of data fragments (for example, first plurality 7D1-1, 7D1-2, 7D1-k, and second plurality 7D2-1, 7D2-2, 7D2-k) using a first erasure-coding scheme; and stream each of the pluralities of data fragments respectively into the plurality of data interfaces (for example, 7D1-1, 7D1-2, and 7D1-k into 523-1, 523-2, and 523-k, respectively), such that a plurality of sub-streams 7STR1, 7STR2, 7STRk of data fragments are created in conjunction with the plurality of data interfaces. Further, each of the data interfaces 523-1, 523-2, 523-k is configured to (i) receive one of said sub-streams of data fragments (for example, 523-1 receiving sub-stream 7STR1 containing fragments 7D1-1 and 7D2-1), and (ii) write in real-time each of the data fragments in the sub-stream into the respective memory module (for example, into memory module 540-m1 associated with data interface 523-1) using a random-access write cycle 7WR1. One result of this embodiment is a real-time erasure-coding of the stream 7STR of data sets into the shared memory pool 512 as facilitated by the first erasure-coding interface 741-1 and multiple random-access write cycles 7WR1, 7WR2, 7WRk, each of which is associated with a data interface 523-1, 523-2, 523-k. 
In an alternative embodiment to the system 740 just described to stream data resiliently into a shared memory pool 512, further the plurality of memory modules 540-m1, 540-m2, 540-mk are based on random-access-memory (RAM), and therefore the random-access write cycles 7WR1, 7WR2, 7WRk allow the writing to proceed at data rates that support the first compute element 700-c1 in writing the data sets 712-D1, 712-D2, after said conversion, at data rates that are limited only by the ability of the first compute element 700-c1 to communicate.
In one possible configuration of the alternative embodiment just described, further the random-access-memory 540-m1, 540-m2, 540-mk is a dynamic-random-access-memory (DRAM), and the first erasure-coding interface 741-1 is communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k using a switching network selected 550 from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network. One result of this possible configuration is that any one of the data sets 712-D1, 712-D2 is written in the plurality of memory modules 540-m1, 540-m2, 540-mk no later than 5 (five) microseconds from being put in said stream 7STR. In one embodiment, said random-access write cycles 7WR1, 7WR2, 7WRk are done simultaneously, as facilitated by the plurality of data interfaces 523-1, 523-2, 523-k acting together, thereby facilitating said bound of 5 (five) microseconds.
In a second possible configuration of the alternative embodiment described above to the system 740 operative to stream data resiliently into a shared memory pool 512, further the random-access-memory 540-m1, 540-m2, 540-mk is a dynamic-random-access-memory (DRAM), and the first erasure-coding interface 741-1 is communicatively connected with the plurality of data interfaces 523-1, 523-2, 523-k using a switching network 550 selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network. One result of this possible configuration is that a rate at which the data sets 712-D1, 712-D2 are being written is at least 100 Giga-bits-per second.
FIG. 22A illustrates one embodiment of a system 760 operative to communicate, via a memory network 760-mem-net, between compute elements 500-c1, 500-c2 and external destinations 7DST. The system includes a plurality of compute elements 500-c1, 500-c2, a memory network 760-mem-net, and a gateway compute node 500-gate. The gateway compute node 500-gate is configured to obtain 761-obt, from the plurality of compute nodes 500-c1, 500-c2, via the memory network 760-mem-net, using a first communication protocol adapted for low latency transmissions, a plurality of general communication messages 7mes intended for a plurality of destinations 7DST external to the system 760. The first communication protocol may be the same communication protocol used in a switching network 550 (FIG. 22B), or be another communication protocol adapted for low latency transmissions. The gateway compute node 500-gate is also configured to transmit 762-TR the plurality of general communication messages 7mes to said plurality of destinations 7DST external to the system, via a general communication network 760-gn, using a second communication protocol adapted for the general communication network 760-gn. 
FIG. 22B illustrates one embodiment of a system 760 operative to communicate, via a switching network 550, between compute elements 500-c1, 500-c2 and memory modules 540-m1, 540-m2, 540-mk storing data sets 512-Dn, 512-D1, 512-D2, respectively. The system 760 includes a plurality of compute elements 500-c1, 500-c2, which may be in a separate server 560-S-1. FIG. 22B shows a first compute element 500-c1 in a separate server 560-S-1, and a second compute element 500-c2 which is not part of a separate server, but it is understood that multiple compute elements may be contained with a single separate server, or each compute element may be part of its own separate server, or none of the compute elements may be part of any separate server. The plurality of compute elements 500-c1, 500-c2 are configured to access 512-D1-TR, 512-D2-TR the plurality of data sets 512-D1, 512-D2, 512-Dn via the switching network 550 using the first communication protocol adapted for low latency transmissions, thereby resulting in the memory network 760-mem-net having a first latency performance in conjunction with the access. FIG. 22B illustrates one possible embodiment of the memory network 760-mem-net illustrated in FIG. 22A. In FIG. 22B, the memory network 760-mem-net includes a switching network 550 and a shared memory pool 512.
The shared memory pool includes the memory modules 540-m1, 540-m2, 540-mk, including the data sets 512-Dn, 512-D1, 512-D2, respectively. Data interfaces 523-1, 523-2, 523-3 are associated with the memory modules, 540-m1, 540-m2, 540-mk, respectively, and are communicatively connected with the switching network 550. FIG. 22B shows the first memory module 540-m1 and first data interface 523-1 included in a separate server 560-S-2, whereas the other memory modules 540-m2, 540-mk and their respective data interfaces 523-2, 523-k, are not included in separate server 560-S-2 or in any other separate server. However, it is understood that any combination of separate servers is possible, including no servers for any of the memory modules or data interfaces, a single separate server for all of the memory modules and data interfaces, each pair of a memory module and its associated data interface in a separate module, or some pairs of memory modules and data interfaces in separate servers while other pairs are not in separate servers. The system 760 also includes the gateway compute node 550-gate, which, as shown in FIG. 22B, is in a separate server 560-S-3, but which in alternative embodiments may be part of another server with other element of the system 760, and in additional alternative embodiments is not placed in a separate server.
The system 760 achieves communication with the destinations 7DST via the memory network 760-mem-net, while simultaneously achieving, using the memory network 760-mem-net, the access 512-D1-TR, 512-D2-TR by the plurality of compute elements 500-c1, 500-c2 to the plurality of data sets 512-D1, 512-D2, 512-Dn in conjunction with the first latency performance associated with such access. One result is that the low latency between the compute elements 500-c1, 500-c2 and the data sets 512-D1, 512-D2, 512-Dn is preserved with no negative impact by communications between the compute element 500-c1, 500-c2 and the plurality of external destinations 7DST. The forwarded communication (transmission 762-TR) with the external destinations 7DST, that is, from the gateway compute node 500-gate to the external destinations 7DST, uses a second communication protocol that may or may not be low latency, since the latency of communication between the compute elements 500-c1, 500-c2 and the external destinations 7DST is generally less critical for system performance than latency between the compute elements 500-c1, 500-c2 and the data sets 512-Dn, 512-D2, 512-D2.
One embodiment is a system 760 operative to communicate with destinations 7DST external to the system 760 via a memory network 760-mem-net. In a particular embodiment, the system 760 includes a gateway compute node 500-gate, a plurality of compute elements 500-c1, 500-c2, and a memory network 760-mem-net. In a particular embodiment, the memory network 760-mem-net includes a shared memory pool 512 configured to store a plurality of data sets 512-D1, 512-D2, 512-Dn, and a switching network 550. Further, the plurality of compute elements 500-c1, 500-c2 are configured to access 512-D1-TR, 512-D2-TR the plurality of data sets 512-D1, 512-D2, 512-Dn via the switching network 550 using a first communication protocol adapted for low latency transmissions, thereby resulting in the memory network 760-mem-net having a first latency performance in conjunction with the access by the compute elements 500-c1, 500-c2. Further, the gateway compute node 500-gate is configured to obtain 761-obt, from the plurality of compute nodes 500-c1, 500-c2, via the memory network 760-mem-net, using the first communication protocol or another communication protocol adapted for low latency transmissions, a plurality of general communication messages 7mes intended for a plurality of destinations 7DST external to the system 760. The gateway compute node 500-gate is further configured to transmit 762-TR the plurality of general communication messages 7mes to the plurality of destinations 7DST external to the system 760, via a general communication network 760-gn, using a second communication protocol adapted for the general communication network 760-gn. One result is that the system 760 achieves the communication with the destinations 7DST via the memory network 760-mem-net, while simultaneously achieving, using the memory network, the access 512-D1-TR, 512-D2-TR to the plurality of data sets 512-D1, 512-D2, 512-Dn in conjunction with said first latency performance.
In a first alternative embodiment to the system just described, further the switching network 550 is a switching network selected from a group consisting of: (i) a non-blocking switching network, (ii) a fat tree packet switching network, and (iii) a cross-bar switching network, thereby facilitating the access 512-D1-TR, 512-D2-TR being simultaneous in conjunction with at least some of the plurality of data sets 512-D1, D2, 512-Dn, such that at least one 512-D1 of the data sets is accessed simultaneously with at least another 512-D2 of the data sets, thereby preventing delays associated with the access, thereby further facilitating the first latency performance in conjunction with the first communication protocol.
In a second alternative embodiment to the system described above, further the shared memory pool 512 includes a plurality of memory modules 540-m1, 540-m2, 540-mk associated respectively with a plurality of data interfaces 523-1, 523-2, 523-k communicatively connected with the switching network 550, in which the plurality of data sets 512-D1, 512-D2, 512-Dn are distributed among the plurality of memory modules, such that each data interface (e.g., 523-2) is configured to extract from its respective memory module (e.g., 540-m2) the respective data set (e.g., 512-D1) simultaneously with another of the data interfaces (e.g., 523-k) extracting from its respective memory module (e.g., 540-mk) the respective data set (e.g., 512-D2), and such that, as a result, at least one of the data sets (e.g., 512-D1) is transported to one of the compute elements (e.g., 500-c1), in conjunction with the access 512-D1-TR, simultaneously with at least another of the data sets (e.g., 512-D2) being transported to another of the compute elements (e.g., 500-c2) in conjunction with the access 512-D2-TR, thereby preventing delays associated with said access, thereby further facilitating the first latency performance in conjunction with the first communication protocol.
In a first possible configuration of the second alternative embodiment just described, further the memory modules 540-m1, 540-m2, 540-mk are based on random-access-memory (RAM), in which the extraction of the data sets 512-Dn, 512-D1, 512-D21 is performed using random access read cycles, thereby further facilitating the first latency performance in conjunction with said first communication protocol.
In a possible variation of the first possible configuration just described, further, the memory modules 540-m1, 540-m2, 540-mk are based on dynamic-random-access-memory (DRAM), in which the extraction of the data sets 512-Dn, 512-D1, 512-D2 is done in less than 2 (two) microseconds, and the access 512-D1-TR is done in less than 5 (five) microseconds.
In a second possible configuration of the second alternative embodiment described above, further the obtaining 761-obt includes writing, by one or more of the compute elements 500-c1, 500-c2, the general communication messages 7mes into one or more of the memory modules 540-m1, 540-m2, 540-mk, and the obtaining 761-obt includes also reading, by the gateway compute node 500-gate, the general communication messages 7mes from the memory modules 540-m1, 540-m2, 540-mk. 
In a possible variation of the second possible configuration just described, further the writing includes sending, by one of the compute elements 500-c1, 500-c2 to one of the data interfaces 523-1, 523-2, 523-k, via the switching network 550, using a packetized message associated with the first communication protocol, one of the general communication messages 7mes, and the writing further include writing one of the general communication messages 7mes, by the specific data interfaces (e.g., 523-1), to the memory module (e.g., 540-m1) associated with that data interface (523-1), using a random-access write cycle.
In a possible option for the possible variation just described, reading further includes reading one of the general communication messages 7mes, by one of the data interfaces (e.g., 523-1), from the associated memory module (e.g., 540-m1), using a random-access read cycle; and reading also includes sending, by the specific data interface (e.g., 523-1), to the gateway compute node 500-gate, via the switching network 550, using a packetized message associated with the first communication protocol, said one of the general communication messages 7mes. 
In a third alternative embodiment to the system 760 described above, further the first communication protocol is a layer two (L2) communication protocol, in which layer three (L3) traffic is absent from the memory network 760-mem-net, thereby facilitating the first latency performance, and the second communication protocol is a layer three (L3) communication protocol, in which layer three (L3) functionality is added by the gateway compute element 500-gate to the general communication messages 7mes, thereby facilitating the transmission 762-TR of general communication messages 7mes to those of the destinations 7DST that require layer three (L3) functionality such as Internet-Protocol (IP) addressing functionality.
In a fourth alternative embodiment to the system 760 described above, further the first communication protocol does not include a transmission control protocol (TCP), thereby facilitating the first latency performance, and the second communication protocol includes a transmission control protocol, in which relevant handshaking is added by the gateway compute element 500-gate in conjunction with the general communication messages 7mes when relaying the general communication messages to those destinations 7DST requiring a transmission control protocol.
In a fifth alternative embodiment to the system 760 described above, further the switching network 550 is based on Ethernet.
In one configuration of the fifth alternative embodiment just described, further the general communication network 760-gn is at least one network of the Internet.
In a sixth alternative embodiment to the system 760 described above, further the first latency performance is a latency performance in which the access 512-D1-TR, 512-D2-TR of any of the compute elements 500-c1, 500-c2 to any of the data sets 512-D1, 512-D2, 512-Dn is done in less than 5 (five) microseconds.
In a seventh alternative embodiment to the system described above, further the shared memory pool 512 is a key-value-store 621 (FIG. 13A), in which said plurality of data sets 512-D1, 512-D2, 512-Dn are a plurality of values 618-v1, 618-v2, 618-v3 (FIG. 13A) associated respectively with a plurality of keys 618-k1, 618-k2, 618-k3 (FIG. 13A).
In one possible configuration of the seventh alternative embodiment just descried, the system further includes a shared input-output medium 685 (FIG. 13A) associated with a medium controller 685-mc (FIG. 13A), in which both the shared input-output medium 685 (FIG. 13A) and the medium controller 685-mc (FIG. 13A) are associated with one of the compute elements 500-c1 (interchangeable with the compute element 600-c1 illustrated in FIG. 13A). Further, the access 512-D1-TR, 512-D2-TR is a high priority key-value transaction 681-kv-tran (FIG. 13A). Further, one of the compute elements (e.g., 500-c1), in conjunction with the first communication protocol, is configured to initiate the high priority key-value transaction 681-kv-tran (FIG. 13A) in conjunction with the key-value-store 621 (FIG. 13A) via the shared input-output medium 685 (FIG. 13A). Further, the medium controller 685-mc (FIG. 13A), in conjunction with the first communication protocol, is configured to block lower priority transactions 686-tran (FIG. 13A) via the shared input-output medium 685 (FIG. 13A) during at least parts of the high priority key-value transactions 681-kv-tran (FIG. 13A), thereby preventing delays in the access 512-D1-TR, 512-D2-TR, thereby further facilitating said first latency performance.
In a possible variation of the possible configuration just described, further, the shared input-output medium 685 (FIG. 13A) is the switching network 550.
In an eighth alternative embodiment to the system described above, further the obtaining 761-obt includes sending by the compute elements 500-c1, 500-c2 the general communication messages 7mes to the gateway compute node 500-gate using a packetized transmission associated with the first communication protocol directly via the switching network 550.
In a ninth alternative embodiment to the system 760 described above, the system 760 further includes a first server 560-S-1, a second server 560-S-2, and a third server 560-S-3. Further, at least one of the compute nodes 500-c1, 500-c2 is located in the first server 560-S-1, at least a part of the shared memory pool 512 (such as a memory module 540-m1) is located inside the second server 560-S-2, the gateway compute node 500-gate is located inside the third server 560-S-3, and the switching network 550 is located outside the first, second, and third servers. In this ninth alternative embodiment, the memory network 760-mem-net facilitates memory disaggregation in the system 760.
FIG. 23A illustrates one embodiment of a method for facilitating general communication via a switching network 550 currently transporting a plurality of data elements associated with a plurality of memory transactions. In step 1111, a plurality of data sets 512-D1, 512-D2, 512-Dn associated with a plurality of memory transactions 512-D1-TR, 512-D2-TR that are latency critical, are transported, via a switching network 550, using a first communication protocol adapted for low latency transmissions, between a first plurality of compute elements 500-c1, 500-c2 and a plurality of memory modules 540-m1, 540-m2, 540-mk In step 1112, a plurality of general communication messages 7mes are sent 761-obt, via the switching network 550, by the plurality of compute elements 500-c1, 500-c2, respectively, to a gateway compute node 500-gate, using the first communication protocol or another communication protocol adapted for low latency transmissions, thereby keeping the switching network 550 in condition to continue facilitating the plurality of memory transactions 512-D1-TR, 512-D2-TR. In step 1113, the plurality of general communication messages 7mes are communicated, via a general communication network 760-gn, using a second communication protocol adapted for the general communication network 760-gn, by the gateway compute node 500-gate, on behalf of the plurality of compute elements 500-c1, 500-c2, to a plurality of external destinations 7DST.
FIG. 23B illustrates an alternative embodiment of a method for facilitating general communication via a switching network 550 currently transporting a plurality of data elements associated with a plurality of memory transactions. In step 1121, a plurality of data sets 512-D1, 512-D2, 512-Dn associated with a plurality of memory transactions 512-D1-TR, 512-D2-TR are transported, via a switching network 550, using a first communication protocol adapted for said switching network 550, between a first plurality of compute elements 500-c1, 500-c2 and a plurality of memory modules 540-m1, 540-m2, 540-mk In step 1122, a plurality of communication tunnels respectively between said plurality of compute elements 500-c1, 500-c2 and a gateway compute node 500-gate are sustained, using the first communication protocol or another communication protocol adapted for the switching network 550, via the switching network 550. In step 1123, the plurality of tunnels is used by the plurality of compute elements 500-c1, 500-c2 to send a plurality of general communication messages 7mes to the gateway compute node 500-gate. In step 1124, the plurality of general communication messages 7mes are communicated 762-TR, via a general communication network 760-gn, using a second communication protocol adapted for the general communication network 760-gn, by the gateway compute node 500-gate, on behalf of the plurality of compute elements 500-c1, 500-c2, to a plurality of external destinations 7DST.
FIG. 24A illustrates one embodiment of a first system 780 configured to generate automatically a procedure to effectively combine fetching and processing of data sets. The system 780 includes a first database 781-DB storing a code sequence 7-code describing an action to be performed by a target system 780-target separate from the first system 780. Such code sequence 7-code is converted by a first compute element 780-c1 into machine executable instructions 7-exe including a fetching sequence 7-fetch to be executed by the target system 780-target. According to the converted machine executable instructions 7-exe, a second compute element 780-c2 located in the target system 780-c2, will fetch the data set from a data source 782-data located in the target system 780-target, and then process such data set. The fetching-and-processing procedure to be executed by the second compute element 780-c2 is operative to fetch, by the second compute element 780-c2, from the data source 782-data, using the fetching sequence 7-fetch, a first data set 512-D1 belonging to the plurality of data sets. The fetch-and-processing procedure is operative also to conclude, by the second compute element 780-c2, that the first data set 512-D1 has not yet been received in the second compute element 780-c2 due to a first latency associated with the fetch. Therefore, in order to not lose time, and instead of processing the first data set 512-D1 that is not yet available to the second compute element, the second compute element 780-c2 fetches from the data source 782-dataa second data set 512-D2 belonging to the plurality of data sets. The fetch-and-processing procedure is operative also to process, by the second compute element 780-c2, the first data set 512-D1 after such first data set 512-D1 has been received by the second compute element 780-c2 from the data source 782-data. As described herein the code sequence 7-code might be a source code, a high-level computer language code, or other data bits that are not immediately executable by a data processor until the code sequence 7-code has been converted into executable machine language.
FIG. 24B illustrates one embodiment of a second compute element 780-c2 operative to fetch and process data sets 512-D1, 512-D2 according to the machine executable instructions 7-exe, including a depiction of the requests for data sets and the reception of data sets. The second compute element 780-c2, according to the machine executable instructions 7-exe, initiates a process to fetch 78-fetch-1 a first data set 512-D1 stored in the data source 782-data by sending a request to data source 782-data. There will be a latency associated with the receipt 78R1 by the second compute element 780-c2 of the first data set 512-1. During this latency, and in order not to lose time, the second compute element 780-c2, according to the machine executable instructions 7-exe, initiates another process to fetch 78-fetch-2 a second data set 512-D2 stored in the data source 782-data by sending another request to the data source 782-data. The first data set 512-D1 is then received 78R1 from data source 782-data in the second compute element 780-c2. The second compute element 780-c2, after it has received 78R1 the first data set 512-D1, processes 780-p1 this first data set 512-D1. Thereafter, the second compute element 780-c2 receives 78R2 the second data set 512-D2, and afterwards processes 780-p2 the second data set 512-D2, all according to the machine executable instructions 7-exe. 
FIG. 24C illustrates one embodiment of a system 780′ configured to generate automatically a procedure to effectively combine fetching and processing of data sets, in which executable instructions are executed immediately upon their receipt by an executing compute element 780-c2. This system includes (i) a first database 781-DB configured to store an executable code 7-code, (ii) a first compute element 780-c1 configured to convert the executable code 7-code into a sequence of machine executable instructions 7-exe and communicate 78-com the converted machine executable instructions 7-exe to a second compute element 780-c2, and (iii) a target system 780-target including a data source 782-data storing a plurality of data sets 512-D1, 512-D2, and a second compute element 780-c2 configured to execute a fetch-and-processing procedure. The structure of the system 780′ illustrated in FIG. 24C is the same as the system 780 illustrated in FIG. 24A, except that the system 780′ in FIG. 24C includes also, within the overall system 780′, the target system 780-target. The system 780′ in FIG. 24C operates in a manner similar to the system 780 and target system 780-target in FIG. 24A, except that in the system 780′ of FIG. 24C the first compute element 780-c1 communicates 78-com the sequence of executable instructions 7-exe to the second compute element 780-c2 just before the second compute element 780-c2 starts executing the sequence of executable instructions 7-exe in the sequence illustrated in FIG. 24B as 78-fetch-1, 78-fetch-2, 78R1, 780-p1, 78R2, and 780-p2. Hence, both the structure and the execution of the embodiment illustrated in FIG. 24C are different than the structure and the execution of the embodiment illustrated in FIG. 24A.
One embodiment is a system 780 configured to generate automatically a procedure operative to effectively combine fetching and processing of data sets. In a particular embodiment, a first database 781-DB is configured to store a code sequence 7-code describing an action to be performed by a target system 780-target on each of a plurality of data sets 512-D1, 512-D2, in which the action for each of the plurality of data sets comprises (i) fetching the data set from a data source 782-data in the target system 780-target, and (ii) processing the data set fetched. Further, a first compute element 780-c1 has access to the first database 781-DB, and is configured to convert the code sequence 7-code into a sequence of executable instructions 7-exe includes a fetching sequence 7-fetch, in which the sequence of executable instructions 7-exe, when executed by a second compute element 780-c2 of the target system 780-target, results in a fetching-and-processing procedure. Further, the fetching-and-processing procedure is operative to fetch 78-fetch-1 from the data source 782-data, using said fetching sequence 7-fetch, a first data set 512-D1 belonging to the plurality of data sets. The fetching-and-processing procedure is further operative to conclude that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 due to a first latency associated with the fetch 78-fetch-1, and therefore, in order to not lose time, and instead of processing 780-p1 the first data set 512-D1, to fetch 78-fetch-2 from the data source 782-dataa second data set 512-D2 belonging to the plurality of data sets. The fetching-and-processing procedure is further configured to process 780-p1 the first data set 512-D1 after the first data set 512-D1 has been received 78R1 by the second compute element 780-c2.
In a first alternative embodiment to the system just described, the fetching-and-processing procedure is further operative to process 780-p2 the second data set 512-D2 after it has been received by the second compute element 780-c2.
In a possible configuration of the first alternative embodiment just described, the fetching-and-processing procedure is further operative to perform a sequence of additional fetches of additional ones of the plurality of data sets, until all of the data sets have been fetched. In one embodiment of this possible configuration, the additional fetches are done regardless of and asynchronously with reception of the additional ones of the plurality of data sets.
In one possible variation of the possible configuration just described, the fetching-and-processing procedure is further operative to process each of such additional ones of the plurality of data sets as they are received, until all of said data sets have been processed.
In a second alternative embodiment to the system described above to generate automatically a procedure operative to effectively combine fetching and processing of data sets, the system 780 (from FIG. 24A) further includes the target system 780-target and thus becomes a new system 780′ (from FIG. 24B).
In a first possible configuration of the second alternative embodiment just described, further the conversion is performed by the first compute element 780-c1 just before the second compute element 780-c2 starts executing the sequence of machine executable instructions 7-exe. 
In a possible variation of the first possible configuration of the second alternative embodiment just described, further the first compute element 780-c1 communicates 78-com the sequence of machine executable instructions 7-exe to the second compute element 780-c2 just before the second compute element 780-c2 starts executing the sequence of machine executable instructions 7-exe. 
In a second possible configuration of the second alternative embodiment previously described, further the first compute element 780-c1 and the second compute element 780-c2 are a single compute element.
In a third alternative embodiment to the system described to generate automatically a procedure operative to effectively combine fetching and processing of data sets, further the code sequence 7-code is written in a high-level programming language, and the conversion of the code sequence 7-code into machine executable instructions 7-exe is a compilation process.
One embodiment is a system 780′ configured to combine effectively fetching and processing of data sets according to an automatically generated procedure. In a particular embodiment, the system includes a data source 782-data configured to produce, store, or obtain a plurality of data sets 512-D1, 512-D2, a first compute element 780-c1, and a second compute element 780-c2 communicatively connected with said the source 782-data. The system also includes a code sequence 7-code describing an action to be performed on each of the plurality of data sets 512-D1, 512-D2, in which the action for each of the plurality of data sets comprises: (i) fetching the data set from the data source 782-data, and (ii) processing the data set fetched. Further, the first compute element 780-c1 is configured to convert the code sequence 7-code into a sequence of machine executable instructions 7-exe including a fetching sequence 7-fetch in which the sequence of machine executable instructions 7-exe, when executed by the second compute element 780-c2, results in a procedure that combines effectively the fetching of the data sets and the processing of the data sets. Further, the second compute element 780-c2 is configured to receive 78-com and execute the sequence of machine executable instructions 7-exe, thereby implementing the procedure for fetching and processing data sets. Further, the fetching-and-processing procedure is operative to fetch 78-fetch-1 from the data source 782-data, using the fetching sequence 7-fetch, a first data set 512-D1 belonging to the plurality of data sets. The fetching-and-processing procedure is further operative to conclude that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 due to a first latency associated with the fetch 78-fetch-1, therefore, in order to not lose time, and instead of processing 780-p1 the first data set 512-D1, to fetch 78-fetch-2 from the data source 782-dataa second data set 512-D2 belonging to the plurality of data sets. The fetching-and-processing procedure is further operative to process 780-p1 the first data set 512-D1 after it has been received 78R1 by the second compute element 780-c2.
In a first alternative embodiment to the system just described, the system further includes a switching network 550 (FIG. 10B), and the data source 782-data is a data interface 523-1, 523-2, 523-k (FIG. 10B) associated with a shared memory pool 512 (FIG. 10B), in which the data interface is communicatively connected with the second compute element 780-c2 via the switching network 550 (FIG. 10B). In this embodiment, the second compute element 780-c2 is interchangeable with the plurality of compute elements 500-c1, 500-c2, 500-cn illustrated in FIG. 10B.
In one possible configuration of the first alternative embodiment just described, further the plurality of data sets 512-D1, 512-D2 is a plurality of values 618-v1, 618-v2 (FIG. 11A) associated respectively with a plurality of keys 618-k1, 618-k2 (FIG. 11A). In this embodiment, the switching network illustrated as element 550 in FIG. 10B is interchangeable with the switching network illustrated as element 650 in FIG. 11A. Further, it should be understood that the key value system depicted as element 621 in FIG. 11A may be implemented, in some embodiments, using the shared memory pool illustrated as element 512 in FIG. 10B. In this sense the key value system 621 and the shared memory pool 512 may be considered interchangeable in the context of the data sets represented by the values associated with the keys in the key value system.
In one possible variation of the first possible configuration just described, further the fetching sequence 7-fetch is operative to send to the data interface 523-1, 523-2, 523-k (FIG. 10B), via the switching network 650 (FIG. 11A), one of the keys 618-k1 (FIG. 11A) in the plurality of keys 618-k1, 618-k2, 618-k3, thereby allowing the data interface to find one of the values 618-v1 (FIG. 11A) in the plurality of values 618-v1, 618-v2, 618-v3 that is associated with the one of the keys sent. The fetching sequence 7-fetch is further operative to receive from the data interface 523-1, 523-2, 523-k3, via the switching network 650, the one of the values found 618-v1.
In one possible option to the possible variation just described, further the first latency is associated with a time required for one of plurality of keys 618-k1, 618-k2, 618-k3 to arrive at the data interface 523-1, 523-2, 523-k. The first latency is further associated with a time required for finding the one of the values 618-v1. The first latency is further associated with the time required for the reception by the second compute element 780-c2 of the one of the values 618-v1.
In a second alternative embodiment to the system described above that is configured to combine effectively fetching and processing of data sets according to an automatically generated procedure, further the data source 782-data is a shared input-output medium 685 (FIG. 13A). Further, the fetching 78-fetch-1, 78-fetch-2 in conjunction with the data sets 512-D1, 512-D2, is associated with a memory transaction or a key-value transaction 681-kv-tran (FIG. 13A) conveyed via the shared input-output medium 685 (FIG. 13A).
In a first possible configuration of the second alternative embodiment just described, further the first latency is associated with a delay in the fetching 78-fetch-1, 78-fetch-2 resulting from any general communication transaction 686-tran (FIG. 13A) conveyed via the shared input-output medium 685 (FIG. 13A).
In a second possible configuration of the second alternative embodiment described above, further the shared input-output medium 685 (FIG. 13A) is based on an interconnect element selected from a group consisting of: (i) peripheral-component-interconnect-express (PCIE) computer expansion bus, (ii) Ethernet, and (iii) Infiniband.
FIG. 25 illustrates one embodiment of a method for generating a sequence of executable instructions operative to combine effecting fetching and processing of data sets. In step 1131, a first compute element 780-c1 receives a code sequence 7-code describing an action to be performed on each of a plurality of data sets 512-D1, 512-D2, in which the action for each of the plurality of data sets comprises: (i) fetching the data set from a data source 782-data, and (ii) processing the data set fetched. In step 1132, the first compute element 780-c1 identifies, in the code sequence 7-code: a first code component describing the fetching (for example, a “get” instruction, or an equation having an argument that needs to be fetched from somewhere), and a second code component 780-c2 describing the processing to be done in conjunction with each data set fetched (for example, a mathematical expression acting on the argument). In step 1133, the first compute element 780-c1 selects, based on (i) the identification, and on (ii) at least a first characteristic of the data sets 512-D1, 512-D2, a fetching sequence suitable for the fetching. As just one example, if the data sets are key-value pairs, then a fetching of a value using a key is used. In step 1134, the first compute element converts the code sequence 7-code into a sequence of machine executable instructions 7-exe including at least one instance of the fetching sequence selected 7-fetch, in which the sequence of machine executable instructions 7-exe, when executed, results in a fetching-and-processing procedure. Further, the fetching-and-processing procedure is operative to have a second compute element 780-c1 fetch 78-fetch-1, from the data source 782-data, using the fetching sequence 7-fetch, a first data set 512-D1 belonging to the plurality of data sets 512-D1, 512-D2. The fetching-and-processing procedure is further operative to have the second compute element 780-c2 conclude that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 due to a first latency associated with the fetch 78-fetch-1. Therefore, in order to not lose time, and instead of processing 780-p1 the first data set 512-D1, the procedure is operative to have the second compute element 780-c2 fetch 78-fetch-2 from the data source 782-dataa second data set 512-D2 belonging to the plurality of data sets 512-D1, 512-D2. The fetching-and-processing procedure is further operative to have the second compute element 780-c2 process the first data set 512-D1 after it has been received 78R1 by the second compute element 780-c2.
In a first alternative embodiment to the method just described, further the second compute element's 780-c2 conclusion that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 is a default condition when no interrupt associated with reception of the first data set 512-D1 has been detected by the second compute element 780-c2, thereby indicating to the second compute element 780-c2 that the first data set 512-D1 is not yet ready for processing by the second compute element 780-c2, thereby facilitating the fetching 78-fetch-2 of the second data set 512-D2 by the second compute element 780-c2.
In one configuration of the first alternative embodiment just described, further the second compute element's 780-c2 conclusion that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 is a passive conclusion in which the fetching 78-fetch-2 of the second data set 512-D2 by the second compute element 780-c2 is done automatically unless interrupted by the interrupt.
In a second alternative embodiment to the method described above for generating a sequence of executable instructions operative to combine effecting fetching and processing of data sets, further the second compute element's 780-c2 conclusion that the first data set 512-D1 has not yet been received 78R1 in the second compute element 780-c2 is reached by second compute element's 780-c2 actively checking for reception 78R1 of the first data set 512-D1 by the second compute element 780-c2.
In a third alternative embodiment to the method described above for generating a sequence of executable instructions operative to combine effecting fetching and processing of data sets, further the code sequence 7-code is a loop in which each iteration of the loop describes an action to be performed on one of the data sets (for example, on the first data set 512-D1) of the plurality of data sets 512-D1, 512-D2 having an index associated with the iteration.
In a fourth alternative embodiment to the method described above for generating a sequence of executable instructions operative to combine effecting fetching and processing of data sets, further the code sequence 7-code describes a single instruction to be performed on multiple data, in which the single instruction is associated with the processing and the multiple data are associated with the plurality of data sets 512-D1, 512-D2. In some embodiments, the single instruction to be performed on multiple data is an SIMD instruction.
One embodiment is a system 780 configured to generate automatically a procedure operative to effectively combine fetching and processing of data sets. In a particular embodiment, a first database 781-DB is configured to store a code sequence 7-code describing an action to be performed by a target system 780-target on each of a plurality of data sets 512-D1, 512-D2, in which the action per each of the plurality of data sets comprises: (i) fetching the data set from a data source 782-data in the target system 780-target, and (ii) processing said data set fetched. Further, a first compute element 780-c1, having access to said first database 781-DB, is configured to convert the code sequence 7-code into a sequence of executable instructions 7-exe comprising a fetching sequence 7-fetch, in which said sequence of executable instructions 7-exe, when executed by a second compute element 780-c2 of the target system 780-target, results in a fetching-and-processing procedure. Further, the fetching-and-processing procedure is operative to fetch 78-fetch-1 from the data source 782-data, using said fetching sequence 7-fetch, a first data set 512-D1 belonging to the plurality of data sets. The fetching-and-processing procedure is further operative to initiate a second fetch 78-fetch-2 from the data source 782-data, using said fetching sequence 7-fetch, for a second data set 512-D2 belonging to the plurality of data sets, in which the initiation is done prior to processing 780-p1 of the first data set 512-D1 that has not yet been received 78R1 in said second compute element 780-c2 due to a first latency associated with the fetching 78-fetch-1 of the first data set 512-D1. The fetching-and-processing procedure is further configured to process 780-p1 the first data set 512-D1 after the first data set 512-D1 has been received 78R1 by the second compute element 780-c2.
FIG. 26 illustrates one embodiment of a system 790 using a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory. As shown in FIG. 26, the system 790 includes a first server 790-S-1 that includes a first compute element 700-c1, and a first random access memory 791-RAM. In some embodiments, the first compute element 700-c1 includes a data set 792-D1-u that has been updated using some aggregated change requirements, and an updated first data 7d1′ which has been extracted by the first compute element 700-c1 from the updated data set 792-D1-u. In some embodiments, the first compute element 700-c1 includes also a plurality of changes to be made to a particular data set, where such changes have been accumulated into an aggregated requirement 792-D1-12, which might be the particular aggregated change requirements that is used to create the updated data set 792-D1-u. In some embodiments, the first server 790-S-1 includes an additional compute element 700-cn, and further there may be three or more compute elements within the first server 790-S-1.
As shown in FIG. 26, the first server 790-S-1 includes also a random access memory 791-RAM, which itself includes multiple change requirements each of which relates to a particular data set with a memory block of a flash memory 792-flash. The various change requirements are accumulated in the random access memory 791-RAM in the order in which they are received, such that requirement 792-D1-r1 is received before 792-D1-r2, which is received before 792-D1-r3. These three change requirements all relate to a first data set 792-D1 in a first memory block 792-B1 within the flash memory 792-flash. However, the receipt of change requirements for a single data set will almost certainly be interspersed with other change requirements related to different data sets. As shown in FIG. 26, change requirement 792-D1-r1 related to data set 792-D1 is received first, then change requirement 792-D2-r1 related to data set 792-D2 in second memory block 792-B2, then change requirement 792-D1-r2 related to the first data set 792-D1, then 792-D2-r2 related to the second data set 792-D2, and finally change requirement 792-D1-r3 related to the first data set 792-D1.
The change requirements in random access memory 791-RAM are executable as data entries, where change requirement 792-D1-r1 is executable as data entry 792-D1-e1, then 792-D2-r1 as 792-D2-e1, 792-D1-r2 as 792-D1-e2, 792-D2-r2 as 792-D2-e2, and 792-D1-r3 as 792-D1-e3. However, in order to perform the execution of changes, each executable data entry related to a particular data set is linked as part of a linked list from an earlier data entry to a later data entry. As shown in FIG. 26, a first linked list 7LL-B1, represented by a boldfaced line segment to the left of 791-RAM, links a first executable data entry 792-D1-e1 related to a first data set 792-D1 to a second executable data entry 792-D1-e2 related to the first data set 792-D1, and also the second executable data entry 792-D1-e3 to a third executable data entry 792-D1-e3 related to the first data set 792-D1. In the embodiment illustrated in FIG. 26, the linkages are made through pointers. So, for example, 792-D1-e1 has pointer 7pt1 which points at the physical address for 792-D1-e2, and 792-D1-e2 has pointer 7pt2 which points at the physical address for 792-D1-e3. In this way, all of the executable data entries for a specific data set are linked, and all of the data entries may be executed when the memory block holding the specific data set is rewritten. For example, all of the data entries for the first data set 792-D1 are executed when the first memory block 792-B1 is rewritten.
Similarly, a second linked list 7LL-B2 shown in FIG. 26 links all of the executable data entries related to the second data set 792-D2. In particular, executable data entry 792-D2-e1 related to the second data set 792-D2 is linked via pointer 7pt1′ to executable entry 792-D2-e2 also related to the second data set 792-D2. When sufficient changes for the second data set 792-D2 have been accumulated, the second data block 792-B2 is rewritten with all of these changes. Second linked list 7LL-B2 is illustrated by the dotted line segment to the right of 791-RAM, connecting the dotted-line boxes with the executable data entries 792-D2-e1 and 792-D2-e2 for the second data set 792-D2.
It should be noted that the last entry illustrated for the first data set 792-D1, which is entry 792-D1-e3, does not have a pointer, and the reason is that there is nothing to point to, because this is the last entry for that data set. If, at some time, a fourth change request is made for the first data set 792-D1, then that fourth change request will generate a fourth executable data entry, at which time a pointer will be added from the third entry 792-D1-e3 to the new fourth executable data entry. Similarly, there is no pointer for executable data entry 792-D2-e2 related to the second data set 792-D2, because this is the last executable data entry for the second data set 792-D2, but if, at some time, a third change request is made for second data set 792-D2, then that third change request will generate a third executable data entry, at which time a pointer will be added from the second entry 792-D2-e2 to the new third executable data entry.
The system 790 illustrated in FIG. 26 includes a flash memory 792-flash, which includes multiple memory blocks 792-B1, 792-B2. As shown, first memory block 792-B1, delineated by a boldfaced rectangle, includes a first data set 792-D1, whereas second memory block 792-B2, delineated by a rectangle created by a dotted line, includes a second data set 792-D2. It will be understood that there may be thousands, millions, or even billions of memory blocks with the flash memory 792-flash, and that each memory block will hold one or more specific data sets. Also, periodically the flash memory 792-flash receives a request to read some data held in the flash memory. For example, as shown in FIG. 26, a request has been received to read some piece of data 7d1 of the first data set 792-D1 stored in the first memory block 792-B1. In response to such request, the first data set 792-D1 is sent to the requesting compute element 700-c1, which uses the aggregated change requirements 792-D1-12 to update the first data set 792-D1 into an updated data set 792-D1-u, which then extracts the required data 7d1′ from the updated data set 792-D1-u. It will be understood that the extracted first data 7d1′ may or may not be identical to the original data requested 7d1. If the aggregated change requirements 792-D1-12 do not impact the specific data requested by the first compute element 700-c1, then the original requested data 7d1 and the extracted data after update 7d1′ will be exactly the same. If on the other hand, the aggregated change requirements 792-D1-12 do impact the specific data requested by the first compute element 700-c1, then the original requested data 7d1 will be different from the extracted data after updated 7d1′, where the first compute element 700-c1 wishes to read and does read the updated data 7d1′.
As illustrated in FIG. 26, the system 790 includes also a second compute element 700-c2, which executes many of the actions further described herein.
The embodiment illustrated in FIG. 26 is illustrative only and non-limiting, in that alternative structures could achieve the same or similar effects. In alternative embodiments, there may be multiple servers. For example, a first server may include only compute elements 700-c1 and 700-cn, whereas a second server may include the random access memory 791-RAM, a third server may include the flash memory 792-flash, and a fourth memory may include a second compute element 700-c2. As a different example, the first server 790-S-1 may include, in addition to the compute elements 700-c1, 700-cn and random access memory 791-RAM as shown, also the flash memory 792-flash. As a different example, the first server 790-S-1 may include only the compute elements 700-c1, 700-cn, whereas a second server could include the random access memory 791-RAM and the flash memory 792-flash. Many different embodiments are conceivable, in which one or more servers include various ones of the compute elements 700-c1, 700-c2, 700-cn, the random access memory 791-RAM, and the flash memory 792-flash. The various alternative structures of the system 790 may also be used to implement the various methods described below.
The embodiment illustrated in FIG. 26 is illustrative and non-limiting, in that alternative pieces of hardware may execute some of the functions described above as being executed by some exemplary piece of hardware. For example, as described above, the first compute element 700-c1 identifies linked lists, traverses linked lists to accumulate change requirements, makes requests to change a data set, updates a data set, and responds to requests by extracting data from an updated data set. Different ones of these functions may be executed by different hardware, so for example, one compute element might identify, traverse, and make requests, but a separate compute element might update data sets and respond to requests by extracting data. As another example, FIG. 26 shows a single compute element 700-c2 executing functions in the flash memory 792-flash, but these functions may be executed by multiple compute elements.
One embodiment is a system 790 operative to use a plurality of linked lists 7LL-B1, 7LL-B2 for keeping track of changes to be made in data sets currently stored in a flash memory 792-flash. In one particular embodiment, the system 790 includes a first compute element 700-c1, and a first flash memory 792-flash comprising a plurality of blocks 792-B1, 792-B2 currently storing respectively a plurality of data sets 792-D1, 792-D2. The system further includes a first random access memory 791-RAM comprising a plurality of linked lists 7LL-B1, 7LL-B2 associated respectively with the plurality of blocks 792-B1, 792-B2, in which each linked list (for example, 7LL-B1) records a respective plurality of requirements 792-D1-r1, 792-D1-r2 to change the data set 792-D1 of the respective block 792-B1, and in which the plurality of requirements 792-D1-r1, 792-D1-r2 were made by the first compute element 700-c1 and have been accumulated 792-D1-e1, 792-D1-e2 in the linked list 7LL-B1 since the data set 792-D1 was last written to the respective block 792-B1. Further, the system 790 is configured to identify one of the linked lists (such as 7LL-B1) as being currently in condition to be used for updating the respective block 792-B1. The system 790 is further configured to traverse the linked list 7LL-B1 identified in order to accumulate all the respective plurality of requirements 792-D1-r1, 792-D1-r2 into an aggregated requirement 792-D1-12 to change the data set 792-D1 of the respective block 792-B1. The system is further configured to change the data set 792-D1 of the respective block 792-B1 by performing a flash block write to the respective block 792-B1 in conjunction with the aggregated requirement 792-D1-12.
In a first possible alternative to the system just described, further each of the linked lists (such as 7LL-B1) comprises a plurality of data entries 792-D1-e1, 792-D1-e2 associated respectively with the plurality of requirements 792-D1-r1, 792-D1-r2, in which each of the data entries (e.g. 792-D1-e1) is linked to the next data entry 792-D1-e2 using a pointer 7pt1 to an address associated with the next such data entry 792-D1-e2, except that the most recent data entry does not yet have a pointer because it has no subsequent data entry to point to.
In a first possible configuration to the first possible alternative just described, further the traversing of the linked list 7LL-B1 is done by performing a random access read cycle to each of the data entries (for example, to 792-D1-e2) in the linked list using the addresses as referenced by the pointers 7pt1, 7pt2. As an example, pointer 7pt1 stores the address associated with data entry 792-D1-e2, such that data entry 792-D1-e2 can be randomly accessed using the address stored in pointer 7pt1. Entry 792-D1-e1 can be randomly accessed using an address stored in a “head” pointer (not depicted) associated with block 792-B1, in which such a head pointer points to the beginning of the linked list 7LL-B1 and is thus used to start such traversing of the linked list 7LL-B1.
In a second possible configuration to the first possible alternative described above, further all the pluralities of data entries (as illustrated in FIG. 26, first plurality 792-D1-e1, 792-D1-e2, 792-D1-e3 and second plurality 792-D2-e1, 792-D2-e2) are stored in a single memory space (for example, a successive series of addresses) within the first random access memory 791-RAM, thereby resulting is the plurality of linked lists 7LL-B1, 7LL-B2 being interlaced across the single memory space, but such that the traversing is possible for each of the linked lists using the pointers (for example, 7pt1 and 7pt2 for linked list 7LL-B1).
In a second possible alternative to the system for using a plurality of linked lists as described above, further identification of one of the linked lists 7LL-B1, 7LL-B2 as being currently in condition to be used for updated its respective block is based on the number of requirements in the plurality of requirements.
In one possible configuration of the second possible alternative just described, further the linked list that is identified is the linked list associated with the highest number of requirements, as compared with the other linked lists.
In a third possible alternative to the system for using a plurality of linked lists as described above, further each of the plurality of requirements (for example, 792-D1-r1, 792-D1-r2, 792-D1-r3 for a first data set 792-D1) is stored in the respective linked list (in this case, first linked list 7LL-B1) as part of a sequence of new data to be written to specific address in the respective block 792-B1.
In one possible configuration of the third possible alternative just described, further the identification is based on the length of the sequences of new data, such that the identification is made when the sequence of new data exceeds a certain threshold length.
In a fourth possible alternative to the system for using a plurality of linked lists as described above, the system 790 further comprises additional compute elements 700-cn, each of which is operative to make additional requirements to change the data set of at least some of the blocks, and in which each such additional compute element necessitates an additional plurality of linked lists in support of the additional requirements, thereby resulting is several pluralities of linked lists. Further, the first random access memory is a shared memory pool (512 in FIG. 10B) which is large enough to store the several pluralities of linked lists.
In a fifth possible alternative to the system for using a plurality of linked lists as described above, the system 790 further comprises a second compute element 700-c2 associated with the first flash memory 792-flash, and a switching network (550 in FIG. 10B). Further, the first random access memory 791-RAM is located in a first server 790-S-1 together with the first compute element 700-c1. Further, the first compute element 700-c1 is configured to perform the identification, traversing, and accumulation in conjunction with the first random access memory 791-RAM. Further, the first compute element 700-c1 is additionally configured to send the aggregated requirement 792-D1-12 accumulated to the second compute element 700-c2 via said switching network (550 in FIG. 10B). Further, the second compute element 700-c2 is configured to receive the aggregated requirement 792-D1-12 and perform the changing using the aggregated requirement received.
In a sixth possible alternative to the system for using a plurality of linked lists as described above, the system 790 further comprises additional compute elements 700-cn, in which the first requirement 792-D1-r1 is made by the first compute element 700-c1, and the second requirement 792-D1-r2 is made by one of the additional compute elements 700-cn, such that the link list 7LL-B1 aggregates requirements from multiple sources.
One embodiment is a system 790 operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory 792-flash. In one particular embodiment, the system includes a first compute element 700-c1, and a first flash memory 792-flash comprising a plurality of blocks 792-B1, 792-B2 currently storing respectively a plurality of data sets 792-D1, 792-D2. The system 790 further includes a first random access memory 791-RAM comprising a plurality of linked lists 7LL-B1, 7LL-B2 associated respectively with the plurality of blocks 792-B1, 792-B2, in which each linked list (for example, first linked list 7LL-B1) records a respective plurality of requirements (for first linked list 7LL-B1, the requirements 792-D1-r1, 792-D1-r2) to change the data set 792-D1 of the respective block 792-B1, in which the plurality of requirements 792-D1-r1, 792-D1-r2 were made by the first compute element 700-c1 and have been accumulated 792-D1-e1, 792-D1-e2 in the linked list 7LL-B1 since the data set 792-D1 was last written to the respective block 792-B1. Further, the first compute element 700-c1 is configured to make a new requirement 792-D1-r3 to change the data set 792-D1 of one of the blocks 792-B1. Further, the system 790 is configured to link the new requirement 792-D1-r3 to the linked list 7LL-B1 associated with said one of the blocks 792-B1, thereby appending the new requirement 792-D1-r3 to the plurality of requirements 792-D1-r1, 792-D1-r2 already associated with the one of the blocks 792-B1.
In a possible alternative to the system just described, further each of the listed links (for example, first listed link 7LL-B1) comprises a plurality of data entries 792-D1-e1, 792-D1-e2 associated respectively with the plurality of requirements 792-D1-r1, 792-D1-r2, in which each of the data entries (for example, 792-D1-e1 for change requirement 792-D1-r1) is linked to the next data entry (in this example, to 792-D1-e2) using a pointer (in this example, 7pt1) to an address associated with the next such data entry, except that the most recent data entry does not yet have a pointer because it has no subsequent data entry to point to. Further, the new change requirement 792-D1-r3 is associated with a new data entry 792-D1-e3. Further, the linkage of the new requirement 792-D1-r3 to the linked list 7LL-B1 is performed by: (i) adding, in conjunction with the most recent data entry 792-D1-e2, and using a first random access write cycle, a new pointer 7pt2 to a new address to be associated with the new data entry 792-D1-e3, and (ii) adding, using a second random access write cycle, at the new address, the new data entry 792-D1-e3.
In a possible configuration of the possible alternative just described, further the linkage is performed in less than one microsecond, as a result of the first random access write cycle and the second random access write cycle being both random access cycles performed in conjunction with the first random access memory 791-RAM.
In a first possible variation of the possible configuration just described, further the first random access memory 791-RAM is a first dynamic random access memory.
In a second possible variation of the possible configuration just described, further the new data entry 792-D1-e3 is less than 500 (five hundred) bytes in length, thereby allowing low latency data writes in conjunction with small data objects such as the new data entry.
In a third possible variation of the possible configuration just described, further the most recent data entry 792-D1-e2 is located using a “tail” pointer (not depicted) associated with block 792-B1, and thus preventing a need to traverse the linked list 7LL-B1 in order to locate the most recent data entry 792-D1-e2, thereby facilitating said linkage being performed in less than one microsecond.
One embodiment is a system 790 operative to use a plurality of linked lists 7LL-B1, 7LL-B2 for keeping track of changes to be made in data sets currently stored in a flash memory. In one particular embodiment, the system includes a first compute element 700-c1, and a first flash memory 792-flash comprising a plurality of blocks 792-B1, 792-B2 currently storing respectively a plurality of data sets 792-D1, 792-D2. The system 790 further includes a first random access memory 791-RAM comprising a plurality of linked lists 7LL-B1, 7LL-B2 associated respectively with the plurality of blocks 792-B1, 792-B2, in which each linked list (for example, first linked list 7LL-B1) records a respective plurality of requirements (for first linked list 7LL-B1, requirements 792-D1-r1, 792-D1-r2) to change the data set (in this example, first data set 792-D1) of the respective block (in this example, 792-B1 for first data set 792-D1), in which the plurality of requirements (in this example, 792-D1-r1, 792-D1-r2) were made by the first compute element 700-c1 and have been accumulated (in this example, 792-D1-e1, 792-D1-e2) in the linked list (in this example, 7LL-B1) since the data set (in this example, 792-D1) was last written to the respective block (in this example 792-B1). Further, the system 790 is configured to: (i) receive a first request to read a first data 7d1 associated with the data set (in this example, first data set 792-D1) stored in one of the blocks (in this example, 792-B1), (ii) read the data set (in this example, 792-D1) from the one of the blocks (in this example, 792-B1), and (iii) traverse the linked list (in this example, first linked list 7LL-B1) associated with the one of the blocks (in this example, 792-B1) in order to accumulate all the respective plurality of change requirements (in this example, 792-D1-r1, 792-D1-r2) into an aggregated requirement 792-D1-12 to change the data set (in this example, first data set 792-D1) of the one of the blocks (in this example, first memory block 792-B1). Further, the system 790 is configured: (i) to update the data set read (in this example, first data set 792-D1), using the aggregated requirement 792-D1-12, into an updated data set 792-D1-u, and (ii) respond to the first request by extracting said first data 7d1′ from the updated data set 792-D1-u. In the embodiment herein described, it is understood that first data 7d1′ extracted may or may not be different than the original first data set 7d1, depending on whether the aggregated requirement 792-D1-12 has changed the first data 7d1. If the aggregated requirement 792-D1-12 has changed the specific data that has been requested, then 7d1′ will be different and more updated than original and not-yet-updated 7d1. If aggregated requirement 792-D1-12 has not changed the specific data that has been requested, then 7d1′ will be the same as 7d1, since the original data would not be changed by a rewrite of the memory block in which the original data 7d1 is located.
FIG. 27 illustrates one embodiment of a method for using as plurality of linked lists for keeping track of changes to be made in data sets stored in a flash memory. In step 1141, a system 790 records, in a first random access memory 791-RAM, a plurality of linked lists 7LL-B1, 7LL-B2 associated respectively with a plurality of blocks 792-B1, 792-B2 of a first flash memory 792-flash, in which each linked list (e.g. 7LL-B1) is a record of a respective plurality of requirements 792-D1-r1, 792-D1-r2 to change a data set 792-D1 associated with the respective block 792-B1. In step 1142, the system 790 identifies one of the linked lists (such as, for example 7LL-B1) as being in condition to be used for updating the respective block (such as block 792-B1). In step 1143, the system 790 traverses the linked list identified 7LL-B1 in order to accumulate all the respective plurality of requirements 792-D1-r1, 792-D1-r2 into a single aggregated requirement 792-D1-12 to change the data set 792-D1 of the associated block 792-B1. In step 1144, the system 790 changes the data set 792-D1 of the respective block 792-B1 by performing a flash block write to the respective block 792-B1 in conjunction with said aggregated requirement 792-D1-12. In some embodiments, steps 1141, 1142 and 1143 are executed by a first compute element 700-c1 within the system 790, and step 1144 is executed by a second compute element 700-c2 within the system 790. It is understood, however, that different compute elements may perform the various steps, or there may be more than two compute elements performing the steps, or a compute element may be combined with other hardware elements, such as, solely for example, the first compute element 700-c1 with the random access memory 791-RAM, or the second compute 700-c2 with the random access memory 791-RAM, or the second compute element 700-c2 with the flash memory 792-flash. 
In this description, numerous specific details are set forth. However, the embodiments/cases of the invention may be practiced without some of these specific details. In other instances, well-known hardware, materials, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. In this description, references to “one embodiment” and “one case” mean that the feature being referred to may be included in at least one embodiment/case of the invention. Moreover, separate references to “one embodiment”, “some embodiments”, “one case”, or “some cases” in this description do not necessarily refer to the same embodiment/case. Illustrated embodiments/cases are not mutually exclusive, unless so stated and except as will be readily apparent to those of ordinary skill in the art. Thus, the invention may include any variety of combinations and/or integrations of the features of the embodiments/cases described herein. Also herein, flow diagram illustrates non-limiting embodiment/case example of the methods, and block diagrams illustrate non-limiting embodiment/case examples of the devices. Some operations in the flow diagram may be described with reference to the embodiments/cases illustrated by the block diagrams. However, the method of the flow diagram could be performed by embodiments/cases of the invention other than those discussed with reference to the block diagrams, and embodiments/cases discussed with reference to the block diagrams could perform operations different from those discussed with reference to the flow diagram. Moreover, although the flow diagram may depict serial operations, certain embodiments/cases could perform certain operations in parallel and/or in different orders from those depicted. Moreover, the use of repeated reference numerals and/or letters in the text and/or drawings is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments/cases and/or configurations discussed. Furthermore, methods and mechanisms of the embodiments/cases will sometimes be described in singular form for clarity. However, some embodiments/cases may include multiple iterations of a method or multiple instantiations of a mechanism unless noted otherwise. For example, a system may include multiple compute elements, each of which is communicatively connected to multiple servers, even though specific illustrations presented herein include only one compute element or a maximum of two compute elements.
Certain features of the embodiments/cases, which may have been, for clarity, described in the context of separate embodiments/cases, may also be provided in various combinations in a single embodiment/case. Conversely, various features of the embodiments/cases, which may have been, for brevity, described in the context of a single embodiment/case, may also be provided separately or in any suitable sub-combination. The embodiments/cases are not limited in their applications to the details of the order or sequence of steps of operation of methods, or to details of implementation of devices, set in the description, drawings, or examples. In addition, individual blocks illustrated in the figures may be functional in nature and do not necessarily correspond to discrete hardware elements. While the methods disclosed herein have been described and shown with reference to particular steps performed in a particular order, it is understood that these steps may be combined, sub-divided, or reordered to form an equivalent method without departing from the teachings of the embodiments/cases. Accordingly, unless specifically indicated herein, the order and grouping of the steps is not a limitation of the embodiments/cases. Embodiments/cases described in conjunction with specific examples are presented by way of example, and not limitation. Moreover, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims and their equivalents.

## Claims

1. A system operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory, comprising:
a first compute element;
a first flash memory comprising a plurality of blocks currently storing respectively a plurality of data sets, in which said first flash memory is associated with a second compute element;
a first random access memory located in a first server together with said first compute element, in which said first random access memory comprises a plurality of linked lists associated respectively with the plurality of blocks, in which each linked list records a respective plurality of requirements to change the data set of the respective block, in which said plurality of requirements were made by said first compute element and have been accumulated in said linked list since the data set was last written to the respective block; and
a switching network;
wherein the first compute element is configured to:
identify one of the linked lists as being currently in condition to be used for updating the respective block;
traverse the linked list identified in order to accumulate all the respective plurality of requirements into an aggregated requirement to change the data set of the respective block; and
send said aggregated requirement accumulated to said second compute element via said switching network;
wherein said second compute element is configured to receive said aggregated requirement and change the data set of the respective block by performing a flash block write to the respective block in conjunction with said aggregated requirement.

2. The system of claim 1, wherein:
each of the linked lists comprises a plurality of data entries associated respectively with the plurality of requirements, in which each of the data entries is linked to the next data entry using a pointer to an address associated with the next such data entry, except to the most recent data entry which does not yet point to another data entry.

3. The system of claim 2, wherein said traversing of the linked list is done by performing a random access read cycle to each of the data entries in the linked list using said addresses as referenced by the pointers.

4. The system of claim 2, wherein:
all the pluralities of data entries are stored in a single memory space within said first random access memory, thereby resulting is said plurality of linked lists being interlaced across the single memory space, but such that said traversing is possible per each of the linked lists using said pointers.

5. The system of claim 1, wherein said identification is based on the number of requirements in the plurality of requirements.

6. The system of claim 5, wherein the linked list identified is the linked list associated with the highest number of requirements, as compared with the other linked lists.

7. The system of claim 1, wherein each of the plurality of requirements is stored in the respective linked list as a sequence of new data to be written to specific address in the respective block.

8. The system of claim 7, wherein said identification is based on the length of said sequences of new data, such that the identification is made when the sequences of new data exceeds a certain threshold length.

9. A system operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory, comprising:
a first compute element;
a first flash memory comprising a plurality of blocks currently storing respectively a plurality of data sets; and
a first random access memory comprising a plurality of linked lists associated respectively with the plurality of blocks, in which each linked list records a respective plurality of requirements to change the data set of the respective block, in which said plurality of requirements were made by said first compute element and have been accumulated in said linked list since the data set was last written to the respective block;
wherein the system is configured to:
identify one of the linked lists as being currently in condition to be used for updating the respective block;
traverse the linked list identified in order to accumulate all the respective plurality of requirements into an aggregated requirement to change the data set of the respective block; and
change the data set of the respective block by performing a flash block write to the respective block in conjunction with said aggregated requirement;
wherein:
said system further comprises additional compute elements each of which is operative to make additional requirements to change the data set of at least some of the blocks, and in which each such additional compute element necessitates an additional plurality of linked lists in support of said additional requirements, thereby resulting is several pluralities of linked lists; and
said first random access memory is a shared memory pool which is large enough to store said several pluralities of linked lists.

10. A system operative to use a plurality of linked lists for keeping track of changes to be made in data sets currently stored in a flash memory, comprising:
a first compute element;
a first flash memory comprising a plurality of blocks currently storing respectively a plurality of data sets; and
a first random access memory comprising a plurality of linked lists associated respectively with the plurality of blocks, in which each linked list records a respective plurality of requirements to change the data set of the respective block, in which said plurality of requirements were made by said first compute element and have been accumulated in said linked list since the data set was last written to the respective block,
wherein the first compute element is configured to make a new requirement to change the data set of one of the blocks; and
the system is configured to link the new requirement to the linked list associated with said one of the blocks, thereby appending the new requirement to the plurality of requirements already associated with said one of the blocks;
wherein:
each of the linked lists comprises a plurality of data entries associated respectively with the plurality of requirements, in which each of the data entries is linked to the next data entry using a pointer to an address associated with the next such data entry, except to the most recent data entry which does not yet point to another data entry;
the new requirement is associated with a new data entry; and
said linkage of the new requirement to the linked list is performed by: (i) adding, in conjunction with said most recent data entry, using a first random access write cycle, a new pointer to a new address to be associated with the new data entry, and (ii) adding, using a second random access write cycle, at the new address, the new data entry, in which said linkage is performed in less than one microsecond, as a result of the first random access write cycle and the second random access write cycle being both random access cycles performed in conjunction with said first random access memory.

11. The system of claim 10, wherein said first random access memory is a first dynamic random access memory.

12. The system of claim 10, wherein said new data entry is less than 500 (five hundred) bytes in length, thereby allowing low latency data writes in conjunction with small data objects such as said new data entry.