Patent Publication Number: US-11392525-B2

Title: Specialized device instantiation onto PCIe fabrics

Description:
BACKGROUND 
     Computer systems typically include bulk storage systems, such as magnetic disk drives, optical storage devices, tape drives, or solid state storage drives, among other storage systems. As storage needs have increased in these computer systems, networked storage systems have been introduced which store large amounts of data in a storage environment physically separate from end user computer devices. These networked storage systems typically provide access to bulk data storage over one or more network interfaces to end users or other external systems. In addition to storage of data, remote computing systems include various processing systems that can provide remote computing resources to end users. These networked storage systems and remote computing systems can be included in high-density installations, such as rack-mounted environments. 
     However, as the densities of networked storage systems and remote computing systems increase, various physical limitations can be reached. These limitations include density limitations based on the underlying storage technology, such as in the example of large arrays of rotating magnetic media storage systems. These limitations can also include computing density limitations based on the various physical space requirements for network interconnect as well as the large space requirements for environmental climate control systems. 
     In addition to physical space limitations, these bulk storage systems have been traditionally limited in the number of devices that can be included per host, which can be problematic in storage environments where higher capacity, redundancy, and reliability is desired. These shortcomings can be especially pronounced with the increasing data storage and retrieval needs in networked, cloud, and enterprise environments. 
     OVERVIEW 
     Disaggregated computing architectures, platforms, and systems are provided herein. In one example, a method of operating a data processing system is provided. The method includes instructing a PCIe fabric communicatively coupling a plurality of physical computing components including PCIe devices and one or more PCIe switches to establish a first PCIe communication path between the management processor and a target PCIe device. The method also includes directing at least configuration data to the target PCIe device using the first PCIe communication path and instructing the PCIe fabric to remove the first PCIe communication path between the management processor and the target PCIe device. The method also includes instructing the PCIe fabric to establish a second PCIe communication path between a selected PCIe device and the target PCIe device configured according to the configuration data. 
     This Overview is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. It may be understood that this Overview is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. While several embodiments are described in connection with these drawings, the disclosure is not limited to the embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents. 
         FIG. 1  is a diagram illustrating a computing platform in an implementation. 
         FIG. 2  is a diagram illustrating management of a computing platform in an implementation. 
         FIG. 3  is a block diagram illustrating a management processor in an implementation. 
         FIG. 4  illustrates example cluster management implementations. 
         FIG. 5  illustrates example cluster management implementations. 
         FIG. 6  is a diagram illustrating components of a computing platform in an implementation. 
         FIG. 7  is a diagram illustrating components of a computing platform in an implementation. 
         FIG. 8  is a diagram illustrating components of a computing platform in an implementation. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a system diagram illustrating computing platform  100 . Computing platform  100  includes one or more management processors  110 , and a plurality of physical computing components. The physical computing components include CPUs of processing modules  120 , Peripheral Component Interconnect Express (PCIe) devices  125 , storage units  130 , network modules  140 , PCIe switch modules  150 , and graphics processing units (GPUs)  170 . These physical computing components are communicatively coupled over PCIe fabric  151  formed from PCIe switch elements  150  and various corresponding PCIe links. PCIe fabric  151  configured to communicatively couple a plurality of plurality of physical computing components and establish compute units using logical partitioning within the PCIe fabric. These compute units, referred to in  FIG. 1  as machine(s)  160 , can each be comprised of any number of central processing units (CPUs) of processing modules  120 , storage units  130 , network interfaces  140  modules, and GPUs  170 , including zero of any module. 
     Computing platform  100  may further include configuration data storage  180  that may communicatively couple with the management processors  110  and which may store configuration data for configuring any of the PCIe devices discussed herein. The term PCIe devices, as used herein, refers to any PCIe-compliant device, which may include PCIe endpoints, PCIe hosts, PCIe root complex devices, or other PCIe devices. These PCIe devices can include processing modules  120 , PCIe devices  125 , storage units  130 , network interfaces  140 , GPUs  170 , among other PCIe devices. 
     The components of platform  100  can be included in one or more physical enclosures, such as rack-mountable units which can further be included in shelving or rack units. A predetermined number of components of platform  100  can be inserted or installed into a physical enclosure, such as a modular framework where modules can be inserted and removed according to the needs of a particular end user. An enclosed modular system, such as platform  100 , can include physical support structure and enclosure that includes circuitry, printed circuit boards, semiconductor systems, and structural elements. The modules that comprise the components of platform  100  are insertable and removable from a rackmount style of enclosure. In some examples, the elements of  FIG. 1  are included in a 2 U chassis for mounting in a larger rackmount environment. It should be understood that the components of  FIG. 1  can be included in any physical mounting environment, and need not include any associated enclosures or rackmount elements. 
     Once the components of platform  100  have been inserted into the enclosure or enclosures, the components can be coupled over the PCIe fabric and logically isolated into any number of separate compute units called “machines” or compute blocks. The PCIe fabric can be configured by management processor  110  to selectively route traffic among the components of a particular processor module and with external systems, while maintaining logical isolation between components not included in a particular processor module. In this way, a flexible “bare metal” configuration can be established among the components of platform  100 . The individual compute blocks can be associated with external users or client machines that can utilize the computing, storage, network, or graphics processing resources of the compute block. Moreover, any number of compute blocks can be grouped into a “cluster” of compute blocks for greater parallelism and capacity. Although not shown in  FIG. 1  for clarity, various power supply modules and associated power and control distribution links can also be included. 
     Turning now to the components of platform  100 , management processor  110  can comprise one or more microprocessors and other processing circuitry that retrieves and executes software, such as user interface  112  and management operating system  111 , from an associated storage system. Processor  110  can be implemented within a single processing device but can also be distributed across multiple processing devices or sub-systems that cooperate in executing program instructions. Examples of processor  110  include general purpose central processing units, application specific processors, and logic devices, as well as any other type of processing device, combinations, or variations thereof. In some examples, processor  110  comprises an Intel® or AMD® microprocessor, ARM® microprocessor, field-programmable gate array (FPGA), application specific integrated circuit (ASIC), application specific processor, or other microprocessor or processing elements. 
     In  FIG. 1 , processor  110  provides interface  113 . Interface  113  comprises a communication link between processor  110  and any component coupled to PCIe fabric  151 . This interface employs Ethernet traffic transported over a PCIe link. Additionally, each processing module  120  in  FIG. 1  is configured with driver  141  which provides for Ethernet communication over PCIe links. Thus, any of processing module  120  and management processor  110  can communicate over Ethernet that is transported over the PCIe fabric. A further discussion of this Ethernet over PCIe configuration is discussed below. 
     A plurality of processing modules  120  are included in platform  100 . Each processing module  120  includes one or more CPUs or microprocessors and other processing circuitry that retrieves and executes software, such as driver  141  and any number of end user applications, from an associated storage system. Each processing module  120  can be implemented within a single processing device but can also be distributed across multiple processing devices or sub-systems that cooperate in executing program instructions. Examples of each processing module  120  include general purpose central processing units, application specific processors, and logic devices, as well as any other type of processing device, combinations, or variations thereof. In some examples, each processing module  120  comprises an Intel® or AMD® microprocessor, ARM® microprocessor, graphics processor, compute cores, graphics cores, application specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other microprocessor or processing elements. Each processing module  120  can also communicate with other compute units, such as those in a same storage assembly/enclosure or another storage assembly/enclosure over one or more PCIe interfaces and PCIe fabric  151 . 
     PCIe devices  125  comprise one or more instances of specialized circuitry, ASIC circuitry, or FPGA circuitry, among other circuitry. PCIe devices  125  each include a PCIe interface comprising one or more PCIe lanes. These PCIe interfaces can be employed to communicate over PCIe fabric  151 . PCIe devices  125  can include processing components, memory components, storage components, interfacing components, among other components. PCIe devices  125  might comprise PCIe endpoint devices or PCIe host devices which may or may not have a root complex. 
     When PCIe devices  125  comprise FPGA devices, example implementations can include Xilinx® Alveo™ (U200/U250/U280) devices, or other FPGA devices which include PCIe interfaces. FPGA devices, when employed in PCIe devices  125 , can receive processing tasks from another PCIe device, such as a CPU or GPU, to offload those processing tasks into the FPGA programmable logic circuitry. An FPGA is typically initialized into a programmed state using configuration data, and this programmed state includes various logic arrangements, memory circuitry, registers, processing cores, specialized circuitry, and other features which provide for specialized or application-specific circuitry. FPGA devices can be re-programmed to change the circuitry implemented therein, as well as to perform a different set of processing tasks at different points in time. FPGA devices can be employed to perform machine learning tasks, implement artificial neural network circuitry, implement custom interfacing or glue logic, perform encryption/decryption tasks, perform blockchain calculations and processing tasks, or other tasks. In some examples, a CPU will provide data to be processed by the FPGA over a PCIe interface to the FPGA. The FPGA can process this data to produce a result and provide this result over the PCIe interface to the CPU. More than one CPU and/or FPGA might be involved to parallelize tasks over more than one device or to serially process data through more than one device. 
     configuration data storage  180 , among other configuration data. In some examples, PCIe devices  125  include locally-stored configuration data which may be supplemented, replaced, or overridden using configuration data stored in configuration data storage  180 . This configuration data can comprise firmware, programmable logic programs, bitstreams, or objects, PCIe device initial configuration data, among other configuration data discussed herein. When PCIe devices  125  include FPGA devices, such as FPGA chips, circuitry, and logic, PCIe devices  125  might also include static random-access memory (SRAM) devices, programmable read-only memory (PROM) devices used to perform boot programming, power-on configuration, or other functions to establish an initial configuration for the FPGA device. In some examples, the SRAM or PROM devices can be incorporated into FPGA circuitry. 
     A plurality of storage units  130  are included in platform  100 . Each storage unit  130  includes one or more storage drives, such as solid state drives in some examples. Each storage unit  130  also includes PCIe interfaces, control processors, and power system elements. Each storage unit  130  also includes an on-sled processor or control system for traffic statistics and status monitoring, among other operations. Each storage unit  130  comprises one or more solid state memory devices with a PCIe interface. In yet other examples, each storage unit  130  comprises one or more separate solid state drives (SSDs) or magnetic hard disk drives (HDDs) along with associated enclosures and circuitry. 
     Storage units  130  might comprise non-volatile storage devices or volatile storage devices. Non-volatile storage devices can include solid state storage media, crosspoint memory, resistive memory, flash memory, phase change memory, or magnetic memory, including combinations thereof. In one example, storage units  130  comprise 3D XPoint devices, such as Intel® Optane™, among others. Volatile storage devices can include memory devices such as dynamic random-access memory (DRAM). In some cases, newer non-volatile memory technologies can be employed as DRAM replacements, such as 3D XPoint memory, resistive random-access memory, magnetic random-access memory, or other technologies. 
     Certain emerging memory technologies, such as 3D Xpoint memory, resistive random-access memory, memristor-based memory, magnetic random-access memory, or others, can comprise non-volatile memory cells with access times and throughputs which meet or exceed DRAM access times and throughputs. Thus, PCIe devices comprising these memory technologies might be employed as either main memory (e.g. as DRAM or cache memory), or as bulk non-volatile storage (e.g. as an SSD). PCIe devices comprising these memory technologies might comprise a memory device with an operational mode selectable among a random-access memory mode and a non-volatile storage drive mode. Configuration data might place the PCIe device into a first “RAM” mode, a second “SSD” mode, or combination modes. Separate subsets of a single PCIe device comprising these memory technologies might be apportioned among different functionality using a shared device PCIe interface. A random-access memory mode for the PCIe device can emulate behavior of a DRAM device or other volatile memory devices used by a CPU for main memory or cache memory or as a memory space for execution of programs by the CPU, even though the memory device might comprise non-volatile memory elements. An access interface, protocol, or presented memory configuration might be aligned with a DRAM device or other volatile memory device. The non-volatile storage drive mode for the PCIe device can instead present behavior of a solid-state storage drive (SSD) or other non-volatile storage device discussed herein. When in the non-volatile storage drive mode, an operating system might be stored to the PCIe device. 
     Configuration data storage  180  may be included in platform  100 . Configuration data storage  180  may include one or more storage drives, such as solid state drives in some examples, or one or more storage units that include one or more storage drives. For example, configuration data storage  180  may comprises one or more solid state memory devices or one or more separate solid state drives (SSDs), magnetic hard disk drives (HDDs), or memory devices, along with associated enclosures and circuitry. Configuration data storage  180  is shown as coupled to the management processors  110  in  FIG. 1 . In such an embodiment, configuration data storage  180  may be coupled to the management processors  110  using any suitable communication link such as PCIe, NVMe, Ethernet, Serial Attached SCSI (SAS), FibreChannel, Thunderbolt, Serial Attached ATA Express (SATA Express), and the like. In other examples, configuration data storage  180  may be coupled to PCIe fabric  151  as described above for storage units  130 . 
     In some examples, configuration data storage  180  may store one or more software configurations. The software configurations may be disk images or installation data that may be deployed to the storage modules  130  by the management processors  110 . In some examples, the software configurations may include operating systems and applications. More particularly, the disk images may include boot images that include operating systems and applications in a form that may be copied to a storage device of the storage modules  130  and then booted from the receiving storage device by a CPU  120 . In other examples, configuration data storage  180  may include installation data that may be installed to a storage device of storage modules  130  to and thereby provide a result similar to the deployment of a boot image to that storage device. 
     Configuration data storage  180  may store configuration data that can include firmware, programmable logic programs or objects, PCIe device initial configuration data, or other configuration data that may be deployed to storage units  130  and may be used in operating the compute units  160  or PCIe devices  125 . Depending on the implementation, configuration data storage  180  may be coupled to one or more of management processors  110  via sideband interfaces, isolated PCIe interfaces, over PCIe fabric  151 , or through various other arrangements. Programmable logic programs or objects can include configuration data or bitstream data that comprises compiled, synthesized, placed, and routed data which can be used to program a programmable logic device or program a memory device which then programs a programmable logic device. 
     Configuration data storage  180  may store configuration data that can include configuration state or state information for PCIe devices. This configuration state can comprise register settings, operational mode selection data, execution state, snapshots, save execution states, or other information. When configuration data comprises configuration state, this configuration state can be used to configure an operational mode of a PCIe device, or to resume execution of one or more software modules deployed to a PCIe device according to the configuration state. This configuration state can set, reset, alter, or otherwise configure any PCIe configuration spaces for PCIe devices, which might comprise Configuration Access Mechanism (CAM) or Enhanced Configuration Access Mechanism (ECAM) registers. In one example, a PCIe device comprises a memory device with an operational mode selectable among a random-access memory mode and a non-volatile storage drive mode. The configuration data might comprise data to change a PCIe device into a selected operational mode, which might entail configuration data to set or alter configuration registers of the PCIe device. 
     A plurality of graphics processing units (GPUs)  170  are included in platform  100 . Each GPU comprises a graphics processing resource that can be allocated to one or more compute units. The GPUs can comprise graphics processors, shaders, pixel render elements, frame buffers, texture mappers, graphics cores, graphics pipelines, graphics memory, or other graphics processing and handling elements. In some examples, each GPU  170  comprises a graphics ‘card’ comprising circuitry that supports a GPU chip. Example GPU cards include nVIDIA® Jetson cards that include graphics processing elements and compute elements, along with various support circuitry, connectors, and other elements. In further examples, other style of graphics processing units or graphics processing assemblies can be employed, such as machine learning processing units, tensor processing units (TPUs), or other specialized processors that may include similar elements as GPUs but lack rendering components to focus processing and memory resources on processing of data. 
     Network interfaces  140  include network interface cards for communicating over TCP/IP (Transmission Control Protocol (TCP)/Internet Protocol) networks or for carrying user traffic, such as iSCSI (Internet Small Computer System Interface) or NVMe (NVM Express) traffic for storage units  130  or other TCP/IP traffic for processing modules  120 . Network interfaces  140  can comprise Ethernet interface equipment, and can communicate over wired, optical, or wireless links. External access to components of platform  100  is provided over packet network links provided by network interfaces  140 . Network interfaces  140  communicate with other components of platform  100 , such as processing modules  120  and storage units  130  over associated PCIe links and PCIe fabric  151 . In some examples, network interfaces are provided for intra-system network communication among for communicating over Ethernet networks for exchanging communications between any of processing modules  120  and management processors  110 . 
     Each PCIe switch  150  communicates over associated PCIe links. In the example in  FIG. 1 , PCIe switches  150  can be used for carrying user data between network interfaces  140 , storage modules  130 , and processing modules  120 . Each PCIe switch  150  comprises a PCIe cross connect switch for establishing switched connections between any PCIe interfaces handled by each PCIe switch  150 . In some examples, each PCIe switch  150  comprises a PLX Technology PEX8725 10-port, 24 lane PCIe switch chip. In other examples, each PCIe switch  150  comprises a PLX Technology PEX8796 24-port, 96 lane PCIe switch chip. 
     The PCIe switches discussed herein can comprise PCIe crosspoint switches, which logically interconnect various ones of the associated PCIe links based at least on the traffic carried by each PCIe link. In these examples, a domain-based PCIe signaling distribution can be included which allows segregation of PCIe ports of a PCIe switch according to user-defined groups. The user-defined groups can be managed by processor  110  which logically integrate components into associated compute units  160  of a particular cluster and logically isolate components and compute units among different clusters. In addition to, or alternatively from the domain-based segregation, each PCIe switch port can be a non-transparent (NT) or transparent port. An NT port can allow some logical isolation between endpoints, much like a bridge, while a transparent port does not allow logical isolation, and has the effect of connecting endpoints in a purely switched configuration. Access over an NT port or ports can include additional handshaking between the PCIe switch and the initiating endpoint to select a particular NT port or to allow visibility through the NT port. 
     Advantageously, this NT port-based segregation or domain-based segregation can allow physical components (i.e. CPU, GPU, FPGA, storage, network, or other PCIe devices) only to have visibility to those components that are included via the segregation/partitioning. Thus, groupings among a plurality of physical components can be achieved using logical partitioning among the PCIe fabric. This partitioning is scalable in nature, and can be dynamically altered as-needed by a management processor or other control elements. The management processor can control PCIe switch circuitry that comprises the PCIe fabric to alter the logical partitioning or segregation among PCIe ports and thus alter composition of groupings of the physical components. These groupings, referred herein as compute units, can individually form “machines” and can be further grouped into clusters of many compute units/machines. Physical components, such as storage drives, processors, or network interfaces, can be added to or removed from compute units according to user instructions received over a user interface, dynamically in response to loading/idle conditions, or preemptively due to anticipated need, among other considerations discussed herein. 
     As used herein, unless specified otherwise, domain and partition are intended to be interchangeable and may include similar schemes referred to as either domain and partition in PCIe and similar network technology. Further, as used herein, unless specified otherwise, segregating and partitioning are intended to be interchangeable and may include similar schemes referred to by one of skill in the art as either segregating and partitioning in PCIe and similar network technology. 
     PCIe can support multiple bus widths, such as ×1, ×2, ×4, ×8, ×16, and ×32, with each multiple of bus width comprising an additional “lane” for data transfer. PCIe also supports transfer of sideband signaling, such as System Management Bus (SMBus) interfaces, as well as associated clocks, power, and bootstrapping, among other signaling. PCIe also might have different implementations or versions employed herein. For example, PCIe version 1.0, 2.0, 3.0 or later (e.g. 4.0, 5.0, and later) might be employed. Moreover, next-generation interfaces can be employed, such as Cache Coherent Interconnect for Accelerators (CCIX), or Open Coherent Accelerator Processor Interface (OpenCAPI). Also, although PCIe is used in  FIG. 1 , it should be understood that different communication links or busses can instead be employed, such as NVMe, Ethernet, Serial Attached SCSI (SAS), Gen-Z, FibreChannel, Thunderbolt, Serial Attached ATA Express (SATA Express), among other interconnect, network, and link interfaces. NVMe (NVM Express) is an interface standard for mass storage devices, such as hard disk drives and solid state memory devices. NVMe can supplant serial ATA (SATA) interfaces for interfacing with mass storage devices in personal computers and server environments. However, these NVMe interfaces are limited to one-to-one host-drive relationship, similar to SATA devices. In the examples discussed herein, a PCIe interface can be employed to transport NVMe traffic and present a multi-drive system comprising many storage drives as one or more NVMe virtual logical unit numbers (VLUNs) over a PCIe interface. 
     Any of the links in  FIG. 1  can each use various communication media, such as air, space, metal, optical fiber, or some other signal propagation path, including combinations thereof. Any of the links in  FIG. 1  can include any number of PCIe links or lane configurations. Any of the links in  FIG. 1  can each be a direct link or might include various equipment, intermediate components, systems, and networks. Any of the links in  FIG. 1  can each be a common link, shared link, aggregated link, or may be comprised of discrete, separate links. 
     In  FIG. 1 , any of the PCIe devices (e.g. management processor  110 , processing module  120 , PCIe device  125 , storage  130 , network interface  140 , GPU  170 ) have configurable logical visibility to other PCIe devices or other PCIe-compliant physical components of platform  100 , as segregated logically by the PCIe fabric. For example, any processing module  120  can transfer data for storage on any storage unit  130  and retrieve data stored on any storage unit  130 . Thus, ‘m’ number of storage drives can be coupled with ‘n’ number of processors to allow for a large, scalable architecture with a high-level of redundancy and density. Furthermore, any processing module  120  can transfer data for processing by any PCIe device  125  or GPU  170  or hand off control of any GPU or PCIe device  125  to another processing module  120 . 
     To provide visibility of each PCIe device to any other PCIe device, various techniques can be employed. In a first example, management processor  110  establishes a cluster that includes one or more compute units  160 . These compute units comprise one or more processing modules  120 , zero or more PCIe devices  125 , zero or more storage units  130 , zero or more network interface units  140 , and zero or more graphics processing units  170 . Elements of these compute units are communicatively coupled by portions of PCIe fabric  151 . Once compute units  160  have been assigned to a particular cluster, further resources can be assigned to that cluster, such as storage resources, graphics processing resources, FPGA logic resources, and network interface resources, among other resources. Management processor  110  can instantiate/bind a subset number of the total quantity of physical resources of platform  100  to a particular cluster and for use by one or more compute units  160  of that cluster. For example, 16 storage drives spanning 4 storage units might be assigned to a group of two compute units  160  in a cluster. The compute units  160  assigned to a cluster then handle transactions for that subset of storage units, such as read and write transactions. 
     Each compute unit  160 , specifically each processor of the compute unit, can have memory-mapped or routing-table based visibility to the PCIe devices, storage units, graphics units, or network units within that cluster, while other units not associated with a cluster are generally not accessible to the compute units until logical visibility is granted. Moreover, each compute unit might only manage a subset of the PCIe device resources, storage resources, or graphics units for an associated cluster. Storage operations, FPGA logic operations, or graphics processing operations might, however, be received over a network interface associated with a first compute unit that are managed by a second compute unit. When a storage operation or graphics processing operation is desired for a resource unit not managed by a first compute unit (i e managed by the second compute unit), the first compute unit uses the memory mapped access or routing-table based visibility to direct the operation to the proper resource unit for that transaction, by way of the second compute unit. The transaction can be transferred and transitioned to the appropriate compute unit that manages that resource unit associated with the data of the transaction. 
     For storage operations, the PCIe fabric is used to transfer data between compute units/processors of a cluster so that a particular compute unit/processor can store the data in the storage unit or storage drive that is managed by that particular compute unit/processor, even though the data might be received over a network interface associated with a different compute unit/processor. For graphics processing operations, the PCIe fabric is used to transfer graphics data and graphics processing commands between compute units/processors of a cluster so that a particular compute unit/processor can control the GPU or GPUs that are managed by that particular compute unit/processor, even though the data might be received over a network interface associated with a different compute unit/processor. For FPGA-based logic processing operations, the PCIe fabric is used to transfer data and FPGA-based logic processing commands between compute units/processors or FPGA devices of a cluster so that a particular compute unit/processor can control the FPGA or FPGAs that are managed by that particular compute unit/processor, even though the data might be received over a network interface associated with a different compute unit/processor. Thus, while each particular compute unit of a cluster actually manages a subset of the total resource units (such as storage drives in storage units or graphics processors in graphics units), all compute units of a cluster have visibility to, and can initiate transactions to, any of resource units of the cluster. A managing compute unit that manages a particular resource unit can receive re-transferred transactions and any associated data from an initiating compute unit by at least using a memory-mapped address space or routing table to establish which processing module handles operations for a particular set of PCIe devices, such as storage operations or other operations. 
     In graphics processing examples, NT partitioning or domain-based partitioning in the switched PCIe fabric can be provided by one or more of the PCIe switches with NT ports or domain-based features. This partitioning can ensure that GPUs can be interworked with a desired compute unit and that more than one GPU, such as more than eight (8) GPUs can be associated with a particular compute unit. Moreover, dynamic GPU-compute unit relationships can be adjusted on-the-fly using partitioning across the PCIe fabric. Shared network resources can also be applied across compute units for graphics processing elements. For example, when a first compute processor determines that the first compute processor does not physically manage the graphics unit associated with a received graphics operation, then the first compute processor transfers the graphics operation over the PCIe fabric to another compute processor of the cluster that does manage the graphics unit. In further examples, memory mapped direct memory access (DMA) conduits can be formed between individual CPU/GPU pairs. This memory mapping can occur over the PCIe fabric address space, among other configurations. To provide these DMA conduits over a shared PCIe fabric comprising many CPUs and GPUs, the logical partitioning described herein can be employed. Specifically, NT ports or domain-based partitioning on PCIe switches can isolate individual DMA conduits among the associated CPUs/GPUs. 
     In FPGA-based processing examples, NT partitioning or domain-based partitioning in the switched PCIe fabric can be provided by one or more of the PCIe switches with NT ports or domain-based features. This partitioning can ensure that PCIe devices comprising FPGA devices can be interworked with a desired compute unit and that more than one FPGA can be associated with a particular compute unit. Moreover, dynamic FPGA-compute unit relationships can be adjusted on-the-fly using partitioning across the PCIe fabric. Shared network resources can also be applied across compute units for FPGA processing elements. For example, when a first compute processor determines that the first compute processor does not physically manage the FPGA associated with a received FPGA operation, then the first compute processor transfers the FPGA operation over the PCIe fabric to another compute processor of the cluster that does manage the FPGA. In further examples, memory mapped direct memory access (DMA) conduits can be formed between individual CPU/FPGA pairs. This memory mapping can occur over the PCIe fabric address space, among other configurations. To provide these DMA conduits over a shared PCIe fabric comprising many CPUs and FPGAs, the logical partitioning described herein can be employed. Specifically, NT ports or domain-based partitioning on PCIe switches can isolate individual DMA conduits among the associated CPUs/FPGAs. 
     In storage operations, such as a write operation, data can be received over network interfaces  140  of a particular cluster by a particular processor of that cluster. Load balancing or other factors can allow any network interface of that cluster to receive storage operations for any of the processors of that cluster and for any of the storage units of that cluster. For example, the write operation can be a write operation received over a first network interface  140  of a first cluster from an end user employing an iSCSI protocol or NVMe protocol. A first processor of the cluster can receive the write operation and determine if the first processor manages the storage drive or drives associated with the write operation, and if the first processor does, then the first processor transfers the data for storage on the associated storage drives of a storage unit over the PCIe fabric. The individual PCIe switches  150  of the PCIe fabric can be configured to route PCIe traffic associated with the cluster among the various storage, processor, and network elements of the cluster, such as using domain-based routing or NT ports. If the first processor determines that the first processor does not physically manage the storage drive or drives associated with the write operation, then the first processor transfers the write operation to another processor of the cluster that does manage the storage drive or drives over the PCIe fabric. Data striping can be employed by any processor to stripe data for a particular write transaction over any number of storage drives or storage units, such as over one or more of the storage units of the cluster. 
     In this example, PCIe fabric  151  associated with platform  100  has 64-bit address spaces, which allows an addressable space of 2 64  bytes, leading to at least 16 exbibytes of byte-addressable memory. The 64-bit PCIe address space can shared by all compute units or segregated among various compute units forming clusters for appropriate memory mapping to resource units. The individual PCIe switches  150  of the PCIe fabric can be configured to segregate and route PCIe traffic associated with particular clusters among the various storage, compute, graphics processing, and network elements of the cluster. This segregation and routing can be establishing using domain-based routing or NT ports to establish cross-point connections among the various PCIe switches of the PCIe fabric. Redundancy and failover pathways can also be established so that traffic of the cluster can still be routed among the elements of the cluster when one or more of the PCIe switches fails or becomes unresponsive. In some examples, a mesh configuration is formed by the PCIe switches of the PCIe fabric to ensure redundant routing of PCIe traffic. 
     Management processor  110  controls the operations of PCIe switches  150  and PCIe fabric  151  over one or more interfaces, which can include inter-integrated circuit (I2C) interfaces that communicatively couple each PCIe switch of the PCIe fabric. Management processor  110  can establish NT-based or domain-based segregation among a PCIe address space using PCIe switches  150 . Each PCIe switch can be configured to segregate portions of the PCIe address space to establish cluster-specific partitioning. Various configuration settings of each PCIe switch can be altered by management processor  110  to establish the domains and cluster segregation. In some examples, management processor  110  can include a PCIe interface and communicate/configure the PCIe switches over the PCIe interface or sideband interfaces transported within the PCIe protocol signaling. 
     Management operating system (OS)  111  is executed by management processor  110  and provides for management of resources of platform  100 . The management includes creation, alteration, and monitoring of one or more clusters comprising one or more compute units. Management OS  111  provides for the functionality and operations described herein for management processor  110 . 
     Management processor  110  also includes user interface  112 , which can present graphical user interface (GUI)  190  to one or more users. User interface  112  and GUI  190  can be employed by end users or administrators to establish clusters, assign assets (compute units/machines) to each cluster, and assign configuration data to individual PCIe devices. In  FIG. 1 , GUI  190  allows end users to create and administer clusters as well as assign one or more machine/compute units to the clusters. GUI  190  provides telemetry information for the operation of system  100  to end users, such as in one or more status interfaces or status views. The state of various components or elements of system  100  can be monitored through GUI  190 , such as processor/CPU state, network state, storage unit state, PCIe element state, among others. User interface  112  can provide other user interfaces than GUI  190 , such as command line interfaces, application programming interfaces (APIs), or other interfaces. In some examples, GUI  190  is provided over a websockets-based interface. 
     One or more management processors can be included in a system, such as when each management processor can manage resources for a predetermined number of clusters or compute units. User commands, such as those received over a GUI, can be received into any of the management processors of a system and forwarded by the receiving management processor to the handling management processor. Each management processor can have a unique or pre-assigned identifier which can aid in delivery of user commands to the proper management processor. Additionally, management processors can communicate with each other, such as using a mailbox process or other data exchange technique. This communication can occur over dedicated sideband interfaces, such as I2C interfaces, or can occur over PCIe or Ethernet interfaces that couple each management processor. 
     Management OS  111  also includes emulated network interface  113 . Emulated network interface  113  comprises a transport mechanism for transporting network traffic over one or more PCIe interfaces. Emulated network interface  113  can emulate a network device, such as an Ethernet device, to management processor  110  so that management processor  110  can interact/interface with any of processing modules  120  over a PCIe interface as if the processor was communicating over a network interface. Emulated network interface  113  can comprise a kernel-level element or module which allows management OS  111  to interface using Ethernet-style commands and drivers. Emulated network interface  113  allows applications or OS-level processes to communicate with the emulated network device without having associated latency and processing overhead associated with a network stack. Emulated network interface  113  comprises a software component, such as a driver, module, kernel-level module, or other software component that appears as a network device to the application-level and system-level software executed by the processor device. 
     In the examples herein, network interface  113  advantageously does not require network stack processing to transfer communications. Instead, emulated network interface  113  transfers communications as associated traffic over a PCIe interface or PCIe fabric to another emulated network device. Emulated network interface  113  does not employ network stack processing yet still appears as network device to the operating system of an associated processor, so that user software or operating system elements of the associated processor can interact with network interface  113  and communicate over a PCIe fabric using existing network-facing communication methods, such as Ethernet communications. 
     Emulated network interface  113  translates PCIe traffic into network device traffic and vice versa. Processing communications transferred to the network device over a network stack is omitted, where the network stack would typically be employed for the type of network device/interface presented. For example, the network device might be presented as an Ethernet device to the operating system or applications. Communications received from the operating system or applications are to be transferred by the network device to one or more destinations. However, emulated network interface  113  does not include a network stack to process the communications down from an application layer down to a link layer. Instead, emulated network interface  113  extracts the payload data and destination from the communications received from the operating system or applications and translates the payload data and destination into PCIe traffic, such as by encapsulating the payload data into PCIe frames using addressing associated with the destination. 
     Management driver  141  is included on each processing module  120 . Management driver  141  can include emulated network interfaces, such as discussed for emulated network interface  113 . Additionally, management driver  141  monitors operation of the associated processing module  120  and software executed by a CPU of processing module  120  and provides telemetry for this operation to management processor  110 . Thus, any user provided software can be executed by CPUs of processing modules  120 , such as user-provided operating systems (Windows, Linux, MacOS, Android, iOS, etc. . . . ) or user application software and drivers. Management driver  141  provides functionality to allow each processing module  120  to participate in the associated compute unit and/or cluster, as well as provide telemetry data to an associated management processor. Each processing module  120  can also communicate with each other over an emulated network device that transports the network traffic over the PCIe fabric. Driver  141  also provides an API for user software and operating systems to interact with driver  141  as well as exchange control/telemetry signaling with management processor  110 . 
       FIG. 2  is a system diagram that includes further details on elements from  FIG. 1 . System  200  includes a detailed view of an implementation of processing module  120  as well as management processor  110 . 
     In  FIG. 2 , processing module  120  can be an exemplary processor in any compute unit or machine of a cluster. Detailed view  201  shows several layers of processing module  120 . A first layer  121  is the hardware layer or “metal” machine infrastructure of processor processing module  120 . A second layer  122  provides the OS as well as management driver  141  and API  125 . Finally, a third layer  124  provides user-level applications. View  201  shows that user applications can access storage, processing/compute (CPU, GPU, or FPGA), and communication resources of the cluster, such as when the user application comprises a clustered storage system or a clustered processing system. 
     As discussed above, driver  141  provides an emulated network device for communicating over a PCIe fabric with management processor  110  (or other processor elements). This is shown in  FIG. 2  as Ethernet traffic transported over PCIe. However, a network stack is not employed in driver  141  to transport the traffic over PCIe. Instead, driver  141  appears as a network device to an operating system or kernel to each processing module  120 . User-level services/applications/software can interact with the emulated network device without modifications from a normal or physical network device. However, the traffic associated with the emulated network device is transported over a PCIe link or PCIe fabric, as shown. API  113  can provide a standardized interface for the management traffic, such as for control instructions, control responses, telemetry data, status information, or other data. 
       FIG. 3  is s block diagram illustrating management processor  300 . Management processor  300  illustrates an example of any of the management processors discussed herein, such as processor  110  of  FIG. 1 . Management processor  300  includes communication interface  302 , user interface  303 , and processing system  310 . Processing system  310  includes processing circuitry  311 , random access memory (RAM)  312 , and storage  313 , although further elements can be included. 
     Processing circuitry  311  can be implemented within a single processing device but can also be distributed across multiple processing devices or sub-systems that cooperate in executing program instructions. Examples of processing circuitry  311  include general purpose central processing units, microprocessors, application specific processors, and logic devices, as well as any other type of processing device. In some examples, processing circuitry  311  includes physically distributed processing devices, such as cloud computing systems. 
     Communication interface  302  includes one or more communication and network interfaces for communicating over communication links, networks, such as packet networks, the Internet, and the like. The communication interfaces can include PCIe interfaces, Ethernet interfaces, serial interfaces, serial peripheral interface (SPI) links, inter-integrated circuit (I2C) interfaces, universal serial bus (USB) interfaces, UART interfaces, wireless interfaces, or one or more local or wide area network communication interfaces which can communicate over Ethernet or Internet protocol (IP) links. Communication interface  302  can include network interfaces configured to communicate using one or more network addresses, which can be associated with different network links. Examples of communication interface  302  include network interface card equipment, transceivers, modems, and other communication circuitry. 
     User interface  303  may include a touchscreen, keyboard, mouse, voice input device, audio input device, or other touch input device for receiving input from a user. Output devices such as a display, speakers, web interfaces, terminal interfaces, and other types of output devices may also be included in user interface  303 . User interface  303  can provide output and receive input over a network interface, such as communication interface  302 . In network examples, user interface  303  might packetize display or graphics data for remote display by a display system or computing system coupled over one or more network interfaces. Physical or logical elements of user interface  303  can provide alerts or visual outputs to users or other operators. User interface  303  may also include associated user interface software executable by processing system  310  in support of the various user input and output devices discussed above. Separately or in conjunction with each other and other hardware and software elements, the user interface software and user interface devices may support a graphical user interface, a natural user interface, or any other type of user interface. 
     RAM  312  and storage  313  together can comprise a non-transitory data storage system, although variations are possible. RAM  312  and storage  313  can each comprise any storage media readable by processing circuitry  311  and capable of storing software and OS images. RAM  312  can include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Storage  313  can include non-volatile storage media, such as solid state storage media, flash memory, phase change memory, or magnetic memory, including combinations thereof. RAM  312  and storage  313  can each be implemented as a single storage device but can also be implemented across multiple storage devices or sub-systems. RAM  312  and storage  313  can each comprise additional elements, such as controllers, capable of communicating with processing circuitry  311 . 
     Software stored on or in RAM  312  or storage  313  can comprise computer program instructions, firmware, or some other form of machine-readable processing instructions having processes that when executed a processing system direct processor  300  to operate as described herein. For example, software  320  can drive processor  300  to receive user commands to establish clusters comprising compute blocks among a plurality of physical computing components that include processing modules, storage modules, and network modules. In some examples, software  320  can drive processor  300  to deploy data from configuration data storage  330  to be utilized in a compute unit (e.g. as a disk image or by performing an installation process, or to program an FPGA). This data can comprise operating system images, pre-installed applications, bootable software images, ISO files, containers, Dockers, virtual nodes, programmable logic bitstreams, programmable logic object files, or other data to a storage device. Software  320  can drive processor  300  to receive and monitor telemetry data, statistical information, operational data, and other data to provide telemetry to users and alter operation of clusters according to the telemetry data or other data. Software  320  can drive processor  300  to manage cluster and compute/graphics unit resources, establish domain partitioning or NT partitioning among PCIe fabric elements, and interface with individual PCIe switches, among other operations. The software can also include user software applications, application programming interfaces (APIs), or user interfaces. The software can be implemented as a single application or as multiple applications. In general, the software can, when loaded into a processing system and executed, transform the processing system from a general-purpose device into a special-purpose device customized as described herein. 
     System software  320  illustrates a detailed view of an example configuration of RAM  312 . It should be understood that different configurations are possible. System software  320  includes applications  321  and operating system (OS)  322 . Software applications  323 - 326  each comprise executable instructions which can be executed by processor  300  for operating a cluster controller or other circuitry according to the operations discussed herein. 
     Specifically, cluster management application  323  establishes and maintains clusters and compute units among various hardware elements of a computing platform, such as seen in  FIG. 1 . User interface application  324  provides one or more graphical or other user interfaces for end users to administer associated clusters and compute units and monitor operations of the clusters and compute units. Inter-module communication application  325  provides communication among other processor  300  elements, such as over I2C, Ethernet, emulated network devices, or PCIe interfaces. User CPU interface  327  provides communication, APIs, and emulated network devices for communicating with processors of compute units, and specialized driver elements thereof. PCIe fabric interface  328  establishes various logical partitioning or domains among PCIe switch elements, controls operation of PCIe switch elements, and receives telemetry from PCIe switch elements. 
     Software  320  can reside in RAM  312  during execution and operation of processor  300 , and can reside in storage system  313  during a powered-off state, among other locations and states. Software  320  can be loaded into RAM  312  during a startup or boot procedure as described for computer operating systems and applications. Software  320  can receive user input through user interface  303 . This user input can include user commands, as well as other input, including combinations thereof. 
     Storage system  313  can comprise flash memory such as NAND flash or NOR flash memory, phase change memory, magnetic memory, among other solid state storage technologies. As shown in  FIG. 3 , storage system  313  includes software  320 . As described above, software  320  can be in a non-volatile storage space for applications and OS during a powered-down state of processor  300 , among other operating software. 
     Processor  300  is generally intended to represent a computing system with which at least software  320  is deployed and executed in order to render or otherwise implement the operations described herein. However, processor  300  can also represent any computing system on which at least software  320  can be staged and from where software  320  can be distributed, transported, downloaded, or otherwise provided to yet another computing system for deployment and execution, or yet additional distribution. 
     The systems and operations discussed herein provide for dynamic assignment of computing resources, graphics processing resources, network resources, or storage resources to a computing cluster. The computing units are disaggregated from any particular cluster or computing unit until allocated by users of the system. Management processors can control the operations of the cluster and provide user interfaces to the cluster management service provided by software executed by the management processors. A cluster includes at least one “machine” or computing unit, while a computing unit include at least a processor element. Computing units can also include network interface elements, FPGA device elements, graphics processing elements, and storage elements, but these elements are not required for a computing unit. 
     Processing resources and other elements (graphics processing, FPGA, network, storage) can be swapped in and out of computing units and associated clusters on-the-fly, and these resources can be assigned to other computing units or clusters. In one example, graphics processing resources can be dispatched/orchestrated by a first computing resource/CPU and subsequently provide graphics processing status/results to another compute unit/CPU. In another example, when resources experience failures, hangs, overloaded conditions, then additional resources can be introduced into the computing units and clusters to supplement the resources. 
     Processing resources can have unique identifiers assigned thereto for use in identification by the management processor and for identification on the PCIe fabric. User supplied software such as operating systems and applications can be deployed to processing resources as-needed when the processing resources are initialized after adding into a compute unit, and the user supplied software can be removed from a processing resource when that resource is removed from a compute unit. The user software can be deployed from a storage system that the management processor can access for the deployment. Storage resources, such as storage drives, storage devices, and other storage resources, can be allocated and subdivided among compute units/clusters. These storage resources can span different or similar storage drives or devices, and can have any number of logical units (LUNs), logical targets, partitions, or other logical arrangements. These logical arrangements can include one or more LUNs, iSCSI LUNs, NVMe targets, or other logical partitioning. Arrays of the storage resources can be employed, such as mirrored, striped, redundant array of independent disk (RAID) arrays, or other array configurations can be employed across the storage resources. Network resources, such as network interface cards, can be shared among the compute units of a cluster using bridging or spanning techniques. Graphics resources (e.g. GPUs) or FPGA resources can be shared among more than one compute unit of a cluster using NT partitioning or domain-based partitioning over the PCIe fabric and PCIe switches. 
       FIGS. 4 and 5  include further detail on a disaggregated computing architecture, such as discussed herein in  FIG. 1  for computing platform  100 . More particularly,  FIGS. 4 and 5  detail example configurations and methods of operating a disaggregated computing architecture. These examples include operating compute units in a clustered environment. The clusters can be formed using one or more compute units that each include a plurality of physical computing components communicatively coupled over a Peripheral Component Interconnect Express (PCIe) fabric. The plurality of physical computing components can be referred to herein as PCIe devices. Although PCIe device  430  is one example of a PCIe device which might comprise a FPGA device or memory device, PCIe device  430  can instead represent any PCIe-compliant device. It should be understood that any of the plurality of physical computing components discussed herein can comprise PCIe devices, whether they comprise PCIe hosts or PCIe endpoints. 
     The physical computing components include at least PCIe devices, FPGA devices, memory devices, central processing units (CPUs), storage modules, graphics processing modules (GPUs), and network interface modules. These physical computing components are all communicatively coupled over a PCIe fabric. The PCIe fabric can isolate the compute units from each other or within clusters in the clustered environment using logical partitioning within the PCIe fabric. Moreover, software components can be deployed by a management processor to at least an associated CPU within each of the compute units responsive to formation of the compute units. Various monitoring functions can be included in the deployed software components, and telemetry can be reported to the management processor related to operation of the compute units. 
     In some examples, a network driver function of the software component is included that emulates operation of a network interface, such as an Ethernet interface, to an operating system of an associated CPU of a compute unit for transfer of communications comprising at least the telemetry to the management processor over the PCIe fabric. The network driver function can include functionality for transferring communications over the PCIe fabric for delivery to the management processor without processing the communications through a network stack. 
     Based at least on the logical partitioning of the PCIe fabric, the compute units have visibility over the PCIe fabric to only a subset of the plurality of physical computing components assigned to each of the compute units within the PCIe fabric. Each particular compute unit lacks visibility over the PCIe fabric to other physical computing components that are communicatively coupled over the PCIe fabric and not assigned to the particular compute unit. However, the logical partitioning can also be configured to form clusters of compute units, where the compute units of the cluster can have visibility to other compute units of the cluster over the PCIe fabric, but be partitioned from having visibility to compute units not of the cluster. Typically, a management processor is configured to instruct the PCIe fabric to establish the logical partitioning within the PCIe fabric by at least forming domain-based PCIe segregation among ports of PCIe switches that comprise the PCIe fabric. However, the management processor can be configured to instruct the PCIe fabric to establish the logical partitioning within the PCIe fabric by at least forming non-transparent (NT) port-based PCIe segregation among ports of PCIe switches that comprise the PCIe fabric. 
     Dynamic alterations to the composition of the compute units and compute clusters can also be achieved. These dynamic alterations can be responsive to user instructions, command line interface (CLI) instructions, graphical user interface (GUI) indications and selections received from users, or by automated processes that detect performance of the compute units and compute clusters. For example, responsive to alteration of the logical partitioning by the management processor, the disaggregated platform changes a composition of the plurality of physical computing components within a compute unit. The composition of the plurality of physical computing components within a compute unit can be altered to include at least one more PCIe device, FPGA, CPU, GPU, memory device, storage module, and network interface module. The composition of the plurality of physical computing components within a compute unit can be altered to reduce a quantity of a PCIe device, FPGA, CPU, GPU, memory device, storage module, and network interface module included in the compute unit. 
     Moreover, clusters can be altered to increase or decrease the number of compute units included therein, such as to increase processing power of a cluster by adding more compute units on-the-fly. Thus, both compute units and clusters can be managed dynamically for enhanced responsiveness to workload, user requirements, scheduling, and other considerations. Since the physical computing components are all coupled via a flexible and configurable PCIe fabric, the physical computing components can be spun-up and spun-down as-needed and in response to various conditions and requirements. In a specific example, a compute unit might not initially be formed with an FPGA or GPU, but later requirements or workload changes might warrant inclusion of a FPGA or GPU or more than one FPGA or GPU into the compute unit. The PCIe fabric partitioning can be altered on-the-fly to allow one or more FPGAs or GPUs to be associated with the CPU or CPUs of the particular compute unit. 
       FIG. 4  illustrates a disaggregated infrastructure  400  highlighting cluster management operating system (OS)  410  executed by a management processor and control of PCIe fabric  420 . The management OS provides for the management, automation, and orchestration of PCIe devices that might include storage, memory, compute, GPU, FPGA, and network elements on PCIe-based fabrics. For example, PCIe device elements  430 , storage elements  434 , central processing elements (CPU)  433 , graphics processing elements (GPU)  432 , and network interface card (NIC) elements  431  are all able to be communicatively coupled over PCIe fabric  420 . The PCIe fabric enables the disaggregated architecture by providing a partition-able communication medium for coupling the various elements into compute units and grouping the compute units into clusters. 
     To provide the disaggregated architecture,  FIG. 4  illustrates a pool of free elements ( 430 - 434 ) that have not yet been assigned to a particular “machine”  440  or compute unit and operating systems and applications  435  present on the free pool of elements ( 430 - 434 ) or that may be deployed to storage devices for use in machines  440 . The free elements are physically present in the associated system but remain idle or unassigned to a particular cluster/machine/compute unit. The management OS can select among the free elements and assign selected ones of the free elements to a machine. Requirements for the machine, such as what tasks the machine is being employed for, can be processed by the management OS to aid in selection of proper PCIe device elements among the free compute, GPU, FPGA, network, memory, and storage elements. Users can interface with graphical or command-line interfaces that allow definition or indication of the requirements or other user targets. 
     The management OS can select among the free elements in response to the user requests. In some examples, the management OS may deploy configuration data  435  to storage devices to be used in a machine  440 . In some examples, the management OS may respond user instructions that specify a particular configuration data  435  to deploy to a PCIe device. In other examples, the user instructions may include one or more fields that identify characteristics for configuration data  435  to be deployed and the management OS may be configured to select configuration data  435  that matches the identified characteristics. Further, in some examples, the user instructions may specify the PCIe device to receive configuration data  435  while, in other examples, the management OS may select the PCIe device, for example, based on user specifications. In addition, where the management OS selects configuration data  435  and PCIe device, the management OS may determine whether a free pool storage device already includes configuration data  435  such that the free pool PCIe device may be allocated to machine  440  without deployment operations. 
     As mentioned above, the management OS may operate to select configuration data  435  and free pool elements based on characteristics specified by the user. In such examples, the management OS can learn to recognize various requests for elements and select suitable elements from the free pool. For example, the management OS can recognize particular user-provided configuration data, such as operating systems, user-provided applications, or user-provided FPGA programming files, and select certain free elements to include in one or more machines based on that recognition. In one example, the operating system to be executed by a particular machine might be specified by a user to be a Linux operating system. Particular elements can be selected from the free pool to enable the machine to run the Linux operating system. User applications, operating systems, storage requirements, interface or traffic requirements, or other considerations can be used to select elements to include in each machine. In another example, a particular FPGA programming state or programming file might be selected for deployment to an FPGA device to be included in machine  440 . 
       FIG. 5  illustrates clustered operation during dynamic “bare metal” orchestration. Several machines are shown for each cluster, with associated machines comprised of physical elements/resources  540  such as CPUs, FPGAs, GPUs, NICs, storage drives, memory devices and other PCIe devices, along with configuration data directed or deployed thereto. The clusters are electrically isolated using PCIe fabric  520 , and a management system can dynamically pull elements/resources from a pool of free elements, such as seen in  FIG. 4 . Thus, one or more physical enclosures, such as a rack-mounted hardware arrangement, can have many elements (i.e. several processors, FPGAs, network interfaces, GPUs, memory devices, storage drives, or other PCIe devices) and these elements can be allocated dynamically among any number of clusters and associated compute units/machines. 
       FIG. 5  illustrates example clusters, 1-N, with any number of clusters possible depending upon the availability of resources to be assigned to machines of the clusters. Although each cluster is shown to have three machines, it should be understood that more or less than three machines per cluster can be utilized. Moreover, each machine in each cluster indicates example elements assigned thereto. These assigned elements can change dynamically according to policy based management, user commands, user instructions, preemptive or predictive allocation, idle/spin-down based removal, or other considerations. One or more management services or control processors can be configured to perform this establishment and alteration of machines and clusters using the PCIe fabric as a medium to couple the various elements dynamically. 
     As previously discussed, in some examples, the computing platform may provide for configuration data deployment, such as FPGA programming, OS image or boot data deployment, in establishing computing units. Such operations are discussed herein with reference to  FIGS. 6-8 .  FIG. 6  provides a flow diagram for use in the platforms and systems which may provide for configuration data deployment in establishing computing units.  FIGS. 7-8  illustrate the operation of the flow diagram of  FIG. 6  in the context of a platform. 
       FIG. 6  includes a flow diagram that illustrates an operational example of configuration data deployment in establishing compute units for any of the systems discussed herein, such as for platform  100  of  FIG. 1 , system  200  of  FIG. 2 , or processor  300  of  FIG. 3 . In  FIG. 6 , operations will be discussed in context of elements of  FIGS. 1 and 2 , although the operations can also apply to those in  FIG. 3 . 
     Management processor  110  may receive ( 601 ) user instructions to establish a compute unit including instructions to deploy configuration data to a PCIe device to be utilized in the compute unit. For example, the user instructions may be received via a user interface as part of user instructions to establish a machine, a cluster of machines, or may be received in instructions to establish a specific compute unit. In some examples, the user instructions may specify the configuration data to deploy by using a pre-established identifier for the configuration data to be deployed. In other examples, the user instructions may include one or more fields that identify characteristics for the configuration data to be deployed and the management processor may be configured to select a configuration data that matches the identified characteristics. Further, in some examples, the user instructions may specify the PCIe device to receive the boot image while, in other examples, the management processor may select the PCIe device, for example based on user specifications. 
     Upon receiving the user instructions to establish the compute unit including instructions to deploy the configuration data, management processor  110  may establish ( 602 ) a logical PCIe domain that includes management processor  110  and a target PCIe device to receive configuration data. In some examples, management processor  110  is communicatively coupled to one or more configuration data storage devices, such as configuration data storage  180  or storage  313 . In further examples, the logical domain may further include the configuration data storage device if, for example, management processor  110  accesses configuration data storage devices via PCIe communications. Various examples for establishing logical domains in PCIe and similar communication systems are discussed above. Referring to previous examples, this may operate to remove the PCIe device from the free pool of devices. Establishing a logical PCIe domain may provide visibility between the management processor and the PCIe device so that the management processor can instantiate the PCIe device on a PCIe interface local to the management processor. In some examples, the management processor may be the only root device visible to the PCIe device in the logical domain, where the PCIe device is an endpoint device in the logical domain. 
     Management processor  110  may then transfer ( 603 ) or otherwise direct the configuration data from the configuration data storage device to the target PCIe device desired to receive the configuration data. In some examples, the configuration data may be a disk image that includes the contents and structure of a disk volume or of an entire data storage device. This configuration data can comprise operating systems, pre-installed applications, bootable software images, ISO files, containers, Dockers, virtual nodes, or other data deployed to a storage device. The contents of a disk image may include an operating system and other applications for operating the compute unit in a state which may be used for booting the stored operating system. In other examples, the management processor may perform an installation and setup process to the target PCIe device, for example, to install an operating system and other applications to a target storage device. In further examples, the configuration data might comprise FPGA programming data, such as bitstream data or object data used to program an FPGA into a desired logic configuration. Input/output (I/O) definitions also might be included in the configuration data when FPGA devices are employed, which can change a pinout or pin transceiver/driver configuration. In yet further examples, the configuration data can comprise data to write into PCIe device configuration registers to configure operation of a PCIe device. This might be employed when a PCIe device has more than one mode of operation, and the configuration data can program the PCIe device to select among the modes of operation. 
     Management processor  110  may then terminate ( 604 ) the logical domain by at least de-establishing the logical domain between management processor  110  and the target PCIe device. In some examples, management processor  110  may also return the target PCIe device that received configuration data to the free pool. In other examples, the management processor may not return the PCIe device to the free pool but change the assignment of the PCIe device to a target compute unit directly. 
     Management processor  110  may allocate ( 605 ) physical resources for a target compute unit including the target PCIe device that received the configuration data and, for example, a CPU or other selected PCIe devices comprising physical components for the compute unit. As with the PCIe device that received the configuration data, depending on the example, the CPU and selected PCIe device physical components for the compute unit may be directly identified by the user instructions, selected by the management processor based on the user instructions, selected by the management processor without reference to the user instructions and so on. 
     At operation  611 , the management processor may establish a logical PCIe domain for the allocated physical resources of the compute unit including the target PCIe device that received the configuration data. In some examples, the establishing of the logical domain may provide visibility between the allocated processor and the target PCIe device that received the configuration data. In some examples, the allocated processor may be the only root device visible to the target PCIe device in the logical domain, while the target PCIe device is an endpoint or non-host on the logical domain. The management processor may then initialize ( 612 ) the compute unit such that the allocated processor of compute unit sees and boots from the target PCIe device that received a boot image in the configuration data. The compute unit may then operate ( 613 ) using the booted OS or other software and data from the target storage device. When FPGA devices are employed, the FPGA device might perform a programming operation to configure logic and/or I/O of the FPGA according to the configuration data. This may require power cycling or reset of the FPGA device in some examples which can be commanded by the management processor, responsive to being attached to a CPU via a logical PCIe domain, or automatically upon receipt of new configuration data. 
     Many variations of the above process can be achieved. For example, while the example process discussed above operates based on user instructions to establish a compute unit or cluster including instructions to deploy a configuration data to a target PCIe device, other examples may determine whether a target PCIe device is available that has an indicated configuration data or software configuration already deployed thereon. If so, the management processor may utilize the already configured target PCIe device or, if not, perform a deployment operation such as that discussed above. Additionally, while the example above discusses configuration data such as boot image or FPGA programming data deployment, in other examples, the software configurations deployed may comprise execution state data, user data, applications, application data, application configurations, operating system customizations, software updates, security patches, partial configuration data sets, or other configuration data. The procedure discussed above may be utilized to deploy any configuration data to any PCIe devices. Further, the procedure discussed above may also be applied to deploying configuration data to a target PCIe device that is then dynamically added to an already initialized and ‘booted’ compute unit. 
       FIGS. 7-8  illustrate the operation of process discussed above with regard to  FIG. 6  in the context of a computing platform  700 . For sake of brevity, the entire discussion of the process of  FIG. 6  will not be repeated and the discussion of  FIG. 6  may be used for additional details for the operations discussed with regard to  FIGS. 7 and 8 . 
       FIG. 7  is presented to illustrate an example of the operation of the process discussed above with regard to  FIG. 6  in the context of a computing platform. In  FIG. 7 , computing platform  700  is presented and performs operations  780 . Computing platform  700  includes a management CPU  710  with an attached configuration data storage device  731 , PCIe fabric  750 , as well assemblies  701 - 703  that house a plurality associated CPUs  761 - 763 , a plurality of storage devices  764 - 766 , a plurality of FPGA devices  767 - 768 , as well as a corresponding PCIe switch  751 - 753  and  757 , respectively. Assemblies  701 - 703  might comprise any chassis, rackmount or “just a box of disks” (JBOD) or “just a bunch of logic” (JBOL) assemblies. A number of PCIe links interconnect the elements of  FIG. 7 , namely PCIe links  753 - 756 . In some examples, PCIe link  755  may comprise a special control/management link that enables administrative or management-level access of control to PCIe fabric  750 . However, it should be understood that similar links to the other PCIe links can instead be employed. In addition, while shown as attached to the management CPU  710 , configuration data storage device  731  may instead be coupled the PCIe fabric  750  instead of the management CPU  710  in other examples. 
     In operation  781 , the management CPU  710  may receive user instructions to establish a compute unit including instructions to deploy configuration data to a target PCIe device to be utilized in the compute unit. In some examples, the user instructions may specify the configuration data to deploy and a target PCIe device to receive the configuration data. In other examples, the management CPU  710  may determine configuration data and target PCIe device, for example, based on the user instructions. In a first example of configuration data deployment in  FIG. 7 , storage device  765  can receive configuration data comprising a boot image. In a second example of configuration data deployment in  FIG. 7 , FPGA device  768  can receive configuration data comprising FPGA programming data. 
     In operation  782 , the management CPU  710  may establish a logical domain that includes the management CPU  710  and a target PCI device. The target PCIe device might be storage device  765  or FPGA device  768 , among other PCIe devices. When storage device  765  is included in the logical domain, logical domain  790  might be formed. When FPGA device  768  is included in the logical domain, logical domain  791  might be formed. Combinations of these logical domains might be formed. In some examples, establishing the logical domain may provide visibility between the management CPU  710  and the target PCIe device over the PCIe fabric. In some example, the logical domain may further include configuration data storage device  731 , for example, if the management CPU  710  accesses configuration data storage device  731  via PCIe communications. 
     In operation  783 , the management CPU  710  may copy the configuration data from configuration data storage device  731  to the target PCIe device. Once the configuration data has been copied, in operation  784 , the management CPU  710  may de-establish the logical domain. In some examples, this may return the target PCIe device to the free pool. In other examples, the management CPU  710  may not reassign the target PCIe device to the free pool but change the domain assignment of the target PCIe device to the compute unit directly. The operations  780  of computing platform  700  continue in  FIG. 8  with operations  880 . 
       FIG. 8  is presented to illustrate an example of the operation of the process discussed above with regard to  FIG. 6  in the context of a computing platform. As previously mentioned, in  FIG. 8 , computing platform  700  is presented and performs operations  880 , which follow operation  784  of  FIG. 7 . 
     In operation  881 , the management CPU  710  may allocate physical resources for the compute unit including a target PCIe device (e.g. storage device  765  or FPGA device  768 ) and an additionally selected PCIe device (e.g. an associated CPU  763  or CPU  762 ). As with the target PCIe device, depending on the example platform, the selected PCIe device and other physical components for the compute unit may be directly identified by the user instructions, selected by the management CPU  710  based on the user instructions, selected by the management CPU  710  without reference to the user instructions and so on. 
     In operation  882 , the management CPU  710  may establish a logical domain for the allocated physical resources of the compute unit including a target PCIe device configurated according to the configuration data and an additional selected PCIe device. In a first example, logical domain  890  is formed that includes storage device  765  and CPU  763 . In a second example, logical domain  891  is formed that includes FPGA device  768  and CPU  762 . In operation  883 , the management CPU  710  may initialize the compute unit such that the target PCIe device of the compute unit employs the configuration data deployed to the target PCIe device. In one example, a selected PCIe device (e.g. CPU  763 ) sees and boots from storage device  765  using a deployed boot image comprising the configuration data. The compute unit including CPU  763  and storage device  765  may then operate using the booted OS in operation  884 . In another example, a selected PCIe device (e.g. CPU  762 ) sees FPGA device  768  and initializes FPGA device  768  for use in logic operations in operation  884 . 
     Storage device  765  might comprise a PCIe device which can operate in a selectable mode of operation, such as a bulk storage mode or a random-access memory mode. Responsive to receiving the configuration data, such a PCIe device can be programmed into a selected mode of operation. For example, when the PCIe device represented by storage device  765  is placed into the bulk storage mode, the PCIe device can operate as a storage drive, such as an SSD or other similar mass storage device. When the PCIe device represented by storage device  765  is placed into the random-access mode, the PCIe device can operate as a RAM device or DRAM-emulated device which provides memory space for execution of programs by CPU  763  or caching of execution-related data by CPU  763 . 
     The functional block diagrams, operational scenarios and sequences, and flow diagrams provided in the Figures are representative of exemplary systems, environments, and methodologies for performing novel aspects of the disclosure. While, for purposes of simplicity of explanation, methods included herein may be in the form of a functional diagram, operational scenario or sequence, or flow diagram, and may be described as a series of acts, it is to be understood and appreciated that the methods are not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a method could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a novel implementation. 
     The descriptions and figures included herein depict specific implementations to teach those skilled in the art how to make and use the best option. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these implementations that fall within the scope of the present disclosure. Those skilled in the art will also appreciate that the features described above can be combined in various ways to form multiple implementations. As a result, the invention is not limited to the specific implementations described above, but only by the claims and their equivalents.