PATENT DOCUMENT

Publication Number: US-10769746-B2
Application Number: US-201414496934-A
Country: US
Kind Code: B2

Title: Data alignment and formatting for graphics processing unit

Abstract:
A data queuing and format apparatus is disclosed. A first selection circuit may be configured to selectively couple a first subset of data to a first plurality of data lines dependent upon control information, and a second selection circuit may be configured to selectively couple a second subset of data to a second plurality of data lines dependent upon the control information. A storage array may include multiple storage units, and each storage unit may be configured to receive data from one or more data lines of either the first or second plurality of data lines dependent upon the control information.

Claims:
What is claimed is: 
     
       1. An apparatus, comprising:
 a first selection circuit configured to selectively couple data bits of a first subset of a plurality of data bits conveyed on a bus to respective data lines of a first plurality of data lines, the first plurality of data lines being column data lines; 
 a second selection circuit configured to selectively couple data bits of a second subset of the plurality of data bits conveyed on the bus to a respective data line of a second plurality of data lines, the second plurality of data lines being row data lines; 
 a first storage array including a plurality of storage units, wherein each storage unit of the plurality of storage units is configured to selectively receive data from at least one data line of the first plurality of data lines or at least one data line of the second plurality of data lines such that various bit positions of the data bits of the first and second subsets are selectively stored in different relative positions within the first storage array; and 
 a second storage array configured to store control information separately from data stored in the first storage array, wherein the first and second selection circuits are coupled to receive control information from the second storage array; 
 wherein each of the first and second selection circuits is configured to store data to conform to a data format employed by a destination of the data. 
 
     
     
       2. The apparatus of  claim 1 , wherein the first selection circuit includes a plurality of multiplex circuits, wherein each multiplex circuit is configured to selectively couple a given data bit of the plurality of data bits to a respective data line of the first plurality of data lines. 
     
     
       3. The apparatus of  claim 1 , wherein the second selection circuits includes a plurality of multiplex circuits, wherein each multiplex circuit is configured to selectively coupled a given data bit of the plurality of data bits to a respective data line of the second plurality of data lines. 
     
     
       4. The apparatus of  claim 1 , wherein each storage unit of the plurality of storage units includes one or more multiplex circuits, wherein each multiplex circuit is configured to receive data from a given data line of the first plurality of data lines or a given data line of a second plurality of data lines. 
     
     
       5. The apparatus of  claim 1 , wherein the first selection circuit is configured to selectively couple the data bits of the first subset of the plurality of data bits to the respective data lines of a first plurality of data lines dependent upon at least a first portion of the control information, and wherein the second selection circuit is configured to selectively couple the data bits of the second subset of the plurality of data bits to the respective data lines of the second plurality of data lines dependent upon at least a second portion of the control information. 
     
     
       6. A method, comprising:
 receiving control information and data from a memory, wherein the data includes a plurality of data bits; 
 storing the control information in a first queue; 
 providing the control information to selection circuits; 
 selecting, using the selection circuits, a subset of the plurality of data bits dependent upon a portion of the control information, wherein selecting includes a first selection circuit selectively coupling data bits of a first subset of the plurality of data bits from a bus to column data lines in a second queue and a second selection circuit selectively coupling a second subset of the plurality of data bits from the bus to row data lines in the second queue, such that various bit positions of the data bits of the first and second subsets are selectively stored in different relative positions within the second queue; and 
 storing the subset of the plurality of data bits into the second queue, the second queue being separate from the first queue, wherein storing the subset of the plurality of data bits further comprise storing the plurality of data bits to conform to a data format employed by a destination of the plurality of data bits. 
 
     
     
       7. The method of  claim 6 , wherein the second queue includes a plurality of data storage units, wherein each data storage unit is coupled to at least one data line of a first plurality of data lines, and at least one data line of a second plurality of data lines. 
     
     
       8. The method of  claim 7 , wherein a given data line of the first plurality of data lines is orthogonal to a respective data line of the second plurality of data lines. 
     
     
       9. The method of  claim 7 , wherein storing the subset of the plurality of data bits comprises storing one or more data bits of the subset of the plurality of data bits in a given one of the plurality of data storage units. 
     
     
       10. The method of  claim 9 , wherein storing the one or more data bits of the subset of the plurality of data bits in the given one of the plurality of data storage units comprises selectively receiving data from either the at least one data line of the first plurality of data lines or the at least one data line of the second plurality of data lines. 
     
     
       11. The method of  claim 6 , wherein storing the control information comprises decoding the control information. 
     
     
       12. The method of  claim 6 , further comprising sending at least a portion of the stored subset of the plurality of data bits to at least one register. 
     
     
       13. A system, comprising:
 a memory; and 
 a graphics unit including a first functional unit and a second functional unit, wherein the graphics unit is configured to:
 receive control information and data from the memory, the data including a plurality of data bits; 
 store the control information in a first queue; 
 provide the control information to selection circuits; 
 select, using the selection circuits, a portion of the data dependent upon a portion of the control information provided from a first queue; and 
 store the portion of the data in a second queue separate from the first queue, wherein the second queue includes a plurality of storage units, and wherein each storage unit of the plurality of storage units is coupled to at least one data line of a first plurality of data lines and at least one data line of a second plurality of data lines, the first plurality of data lines being column data lines and the second plurality of data lines being row data lines; 
 wherein selecting a portion of the data includes a first one of the selection circuits selectively coupling data bits of a first subset of the plurality of data bits from a bus to column data lines in the second queue and a second selection circuit selectively coupling a second subset of the plurality of data bits from the bus to row data lines in the second queue such that various bit positions of the data bits of the portion are selectively stored in different relative positions within the second queue; and 
 wherein storing the portion of the data includes storing the data in a data format conforming to a destination of the portion of data. 
 
 
     
     
       14. The system of  claim 13 , wherein to store the portion of the data in the second queue, the graphics unit is further configured to store the portion of the data into a subset of a plurality of storage units in the second queue dependent upon the control information. 
     
     
       15. The system of  claim 13 , wherein the portion of the data includes a plurality of data bits, and wherein to store the portion of the data in the second queue, the graphics unit is further configured to store a subset of the plurality of data bits into a given one of a plurality of storage unit in the second queue. 
     
     
       16. The system of  claim 15 , wherein to store the subset of the plurality of data bits into the given one of the plurality of storage units in the second queue, the graphics unit is further configured to couple the given one of the plurality of storage units to at least one data line of the first plurality of data lines. 
     
     
       17. The system of  claim 13 , wherein each data line of the first plurality of data lines is orthogonal to a respective data line of the second plurality of data lines.

Description:
BACKGROUND 
     Technical Field 
     Embodiments described herein relate to computer processing and more specifically to register file access. 
     Description of the Related Art 
     Part of the operation of many computer systems, including portable digital devices such as mobile phones, notebook computers and the like, is the use of some type of display device, such as a liquid crystal display (LCD), to display images, video information/streams, and data. Accordingly, these systems typically incorporate functionality for generating images and data, including video information, which are subsequently output to the display device. Such devices typically include graphics processing units to process video and image information for subsequent display. 
     Graphics processing units (GPUs) typically operate on large amounts of graphics data in parallel using multiple execution pipelines or shaders. Modern GPUs are becoming more and more programmable, with less computation done in fixed-function hardware and more computation done using programmable shaders that execute graphics instructions from application developers. Execution of such instructions may consume considerable power, especially in more powerful GPUs. 
     SUMMARY OF THE EMBODIMENTS 
     Various embodiments of a unified shading cluster are disclosed. Broadly speaking, an apparatus and a method are contemplated in which a first selection circuit may be configured to selectively couple each data bit of a first subset of a plurality of data bits to a respective data line of a first plurality of data lines. A second selection circuit may be configured to selectively couple each data bit of a second subset of a plurality of data bits to a respective data line of a second plurality of data lines. A storage array may include a plurality of storage units, where each storage unit may be configured to selectively receive data from at least one data line of the first plurality of data lines or at least one data line of the second plurality of data lines 
     In one embodiment, the first selection circuit may include a plurality of multiplex circuits. Each multiplex circuit may be configured to selectively couple a given data bit of the plurality of data bits to a respective data line of the first plurality of data lines. 
     In a further embodiment, the second selection circuit may include a plurality of multiplex circuits. Each multiplex circuit may be configured to selectively couple a given data bit of the plurality of data bits to a respective data line of the second plurality of data lines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description makes reference to the accompanying drawings, which are now briefly described. 
         FIG. 1  illustrates an embodiment of a computing system. 
         FIG. 2  illustrates an embodiment of a graphics unit. 
         FIG. 3  illustrates an embodiment of a portion of a unified shading cluster. 
         FIG. 4  illustrates an embodiment of a format unit. 
         FIG. 5  illustrates an embodiment of a data queue of a format unit. 
         FIG. 6  illustrates an embodiment of a storage array of a data queue. 
         FIG. 7  illustrates an embodiment of a storage unit of a storage array. 
         FIG. 8  depicts a flow diagram illustrating an embodiment of a method for operating a format unit. 
         FIG. 9  depicts a flow diagram illustrating an embodiment a method formatting data. 
     
    
    
     While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form illustrated, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to. 
     Various units, circuits, or other components may be described as “configured to” perform a task or tasks. In such contexts, “configured to” is a broad recitation of structure generally meaning “having circuitry that” performs the task or tasks during operation. As such, the unit/circuit/component can be configured to perform the task even when the unit/circuit/component is not currently on. In general, the circuitry that forms the structure corresponding to “configured to” may include hardware circuits. Similarly, various units/circuits/components may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase “configured to.” Reciting a unit/circuit/component that is configured to perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112, paragraph (f) interpretation for that unit/circuit/component. More generally, the recitation of any element is expressly intended not to invoke 35 U.S.C. § 112, paragraph (f) interpretation for that element unless the language “means for” or “step for” is specifically recited. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Graphics Processing Units (GPUs) may include multiple registers that may be used in various computations performed by shading units, such as, a vertex shader, for example. A data execution pipeline may read source operands from the registers, perform an operation using the source operands, and the write computed results back to the registers. Many such operations may be performed in parallel. 
     During operation of GPUs, large amounts of data may be moved between registers specific to individual processing pipelines and local memory shared between the various processing pipelines. In some GPUs, multiple queue structures may be employed to store read data for a number of processing cycles before writing the data to a desired memory location. In order to avoid latency and conflict issues, the queue structures may need to be of sufficient size to avoid stalling a GPU. As queue size increases in response to performance and/or architectural needs, scaling issues may arise that may result in wire routing congestion during physical design of a queue structure. 
     Additionally, data received from the local memory may be to be transformed (also referred to herein as “reformatted”) so that the incoming data may be properly directed to its destination. Such transformations may require a large number of multiplex circuits, further complicating the physical design of the queue structure. The embodiments illustrated in the drawing and described below may provide techniques for providing a queue structure that can be scaled while minimizing the impact on wire routing. 
     System Overview 
     Referring to  FIG. 1 , a block diagram illustrating an embodiment of a device  100  is shown. In some embodiments, elements of device  100  may be included within a system-on-a-chip (SoC). In some embodiments, device  100  may be included in a mobile device, which may be battery-powered. Therefore, power consumption by device  100  may be an important design consideration. In the illustrated embodiment, device  100  includes fabric  110 , compute complex  120 , input/output (I/O) bridge  170 , cache/memory controller  145 , graphics unit  150 , and display unit  165 . 
     Fabric  110  may include various interconnects, buses, multiplex circuits (commonly referred to as “MUX&#39;s”), controllers, etc., and may be configured to facilitate communication between various elements of device  100 . In some embodiments, portions of fabric  110  may be configured to implement various different communication protocols. In other embodiments, fabric  110  may implement a single communication protocol and elements coupled to fabric  110  may convert from the single communication protocol to other communication protocols internally. 
     In the illustrated embodiment, compute complex  120  includes bus interface unit (BIU)  125 , cache  130 , and cores  135  and  140 . In various embodiments, compute complex  120  may include various numbers of cores and/or caches. For example, compute complex  120  may include 1, 2, or 4 processor cores, or any other suitable number. In one embodiment, cache  130  is a set associative L2 cache. In some embodiments, cores  135  and/or  140  may include internal instruction and/or data caches. In some embodiments, a coherency unit (not shown) in fabric  110 , cache  130 , or elsewhere in device  100  may be configured to maintain coherency between various caches of device  100 . BIU  125  may be configured to manage communication between compute complex  120  and other elements of device  100 . Processor cores such as cores  135  and  140  may be configured to execute instructions of a particular instruction set architecture (ISA) which may include operating system instructions and user application instructions. 
     Cache/memory controller  145  may be configured to manage transfer of data between fabric  110  and one or more caches and/or memories. For example, cache/memory controller  145  may be coupled to an L3 cache, which may in turn be coupled to a system memory. In other embodiments, cache/memory controller  145  may be directly coupled to a memory. In some embodiments, cache/memory controller  145  may include one or more internal caches. 
     As used herein, the term “coupled to” may indicate one or more connections between elements, and a coupling may include intervening elements. For example, in  FIG. 1 , graphics unit  150  may be described as “coupled to” a memory through fabric  110  and cache/memory controller  145 . In contrast, in the illustrated embodiment of  FIG. 1 , graphics unit  150  is “directly coupled” to fabric  110  because there are no intervening elements. 
     Graphics unit  150  may include one or more processors and/or one or more graphics processing units (GPU&#39;s). Graphics unit  150  may receive graphics-oriented instructions, such OPENGL®, Metal, or DIRECT3D® instructions, for example. Graphics unit  150  may execute specialized GPU instructions or perform other operations based on the received graphics-oriented instructions. Graphics unit  150  may generally be configured to process large blocks of data in parallel and may build images in a frame buffer for output to a display. Graphics unit  150  may include transform, lighting, triangle, and/or rendering engines in one or more graphics processing pipelines. Graphics unit  150  may output pixel information for display images. In the illustrated embodiment, graphics unit  150  includes Unified Shading Cluster (USC)  160 . 
     Display unit  165  may be configured to read data from a frame buffer and provide a stream of pixel values for display. Display unit  165  may be configured as a display pipeline in some embodiments. Additionally, display unit  165  may be configured to blend multiple frames to produce an output frame. Further, display unit  165  may include one or more interfaces (e.g., MIPI® or embedded display port (eDP)) for coupling to a user display (e.g., a touchscreen or an external display). 
     I/O bridge  170  may include various elements configured to implement: universal serial bus (USB) communications, security, audio, and/or low-power always-on functionality, for example. I/O bridge  170  may also include interfaces such as pulse-width modulation (PWM), general-purpose input/output (GPIO), serial peripheral interface (SPI), and/or inter-integrated circuit (I2C), for example. Various types of peripherals and devices may be coupled to device  100  via I/O bridge  170 . 
     It is noted that the embodiment illustrated in  FIG. 1  is merely an example. In other embodiments, different functional units (also referred to herein as “functional blocks”), and different configurations of functional blocks within device  100  are possible and contemplated. 
     Graphics Unit 
     Turning to  FIG. 2 , a simplified block diagram illustrating one embodiment of a graphics unit is shown. Graphics unit  200  may, in various embodiments, corresponding to graphics units  150  as depicted in  FIG. 1 . In the illustrated embodiment, graphics unit  200  includes unified shading cluster (USC)  201 , vertex pipe  202 , fragment pipe  206 , texture processing unit (TPU)  203 , pixel back end (PBE)  205 , and memory interface  204 . In one embodiment, graphics unit  200  may be configured to process both vertex and fragment data using USC  201 , which may be configured to process graphics data in parallel using multiple execution pipelines or instances. 
     Vertex pipe  202 , in the illustrated embodiment, may include various fixed-function hardware configured to process vertex data. Vertex pipe  202  may be configured to communicate with USC  201  in order to coordinate vertex processing. In the illustrated embodiment, vertex pipe  202  is configured to send processed data to fragment pipe  206  and/or USC  201  for further processing. 
     Fragment pipe  206 , in the illustrated embodiment, may include various fixed-function hardware configured to process pixel data. Fragment pipe  206  may be configured to communicate with USC  201  in order to coordinate fragment processing. Fragment pipe  206  may be configured to perform rasterization on polygons from vertex pipe  202  and/or USC  201  to generate fragment data. Vertex pipe  202  and/or fragment pipe  206  may be coupled to memory interface  204  (coupling not shown) in order to access graphics data. 
     USC  201 , in the illustrated embodiment, is configured to receive vertex data from vertex pipe  202  and fragment data from fragment pipe  206  and/or TPU  203 . USC  201  may be configured to perform vertex processing tasks on vertex data which may include various transformations and/or adjustments of vertex data. USC  201 , in the illustrated embodiment, may also be configured to perform fragment processing tasks on pixel data such as texturing and shading, for example. USC  201  may include multiple execution instances for processing data in parallel. USC  201  may be referred to as “unified” in the illustrated embodiment in the sense that it is configured to process both vertex and fragment data. In other embodiments, programmable shaders may be configured to process only vertex data or only fragment data. 
     TPU  203 , in the illustrated embodiment, is configured to schedule fragment processing tasks from USC  201 . In one embodiment, TPU  203  may be configured to pre-fetch texture data and assign initial colors to fragments for further processing by USC  201  (e.g., via memory interface  204 ). TPU  203  may be configured to provide fragment components in normalized integer formats or floating-point formats, for example. In one embodiment, TPU  203  may be configured to provide fragments in groups of four (a “fragment quad”) in a 2×2 format to be processed by a group of four execution instances in USC  201 . 
     PBE  205 , in the illustrated embodiment, is configured to store processed tiles of an image and may perform final operations to a rendered image before it is transferred to a frame buffer (e.g., in a system memory via memory interface  204 ). Memory interface  204  may facilitate communications with one or more of various memory hierarchies in various embodiments. 
     In various embodiments, a programmable shader such as USC  201  may be coupled in any of various appropriate configurations to other programmable and/or fixed-function elements in a graphics unit. The exemplary embodiment of  FIG. 2  shows one possible configuration of a graphics unit  200  for illustrative purposes. 
     Unified Shading Cluster 
     An embodiment of a portion of a Unified Shading Cluster (USC) is illustrated in  FIG. 3 . It is noted, that for the purposes of clarity, some functional units have been omitted from USC  300 . In various other embodiments, USC  300  may include additional functional units. USC  300  may, in various embodiments, correspond to USC  201  as illustrated in  FIG. 2 . The illustrated embodiment includes datapath  301 , Register File  302 , Unified Store Manager (USMGR)  303 , Data Mover  304 , and Unified Store Pipeline Controller (USCPC)  307 . 
     Datapath  301  may include multiple logic circuits configured to perform operations on source operands retrieved from Register File  302 . Upon completion of the operation, results may be written back into Register File  302 . In various embodiments, multiple operations may be performed in parallel. In such cases, Datapath  301  may access data from different banks within Register File  302  in parallel. 
     Register File  302  may include multiple banks, such as, e.g., banks  308   a  and  308   b . Although only two banks are depicted in the embodiment illustrated in  FIG. 3 , any suitable number of banks may be employed in other embodiments. Each bank may be operated independently, and may contain multiple data storage cells. In some embodiments the data storage cells may include both a read port and a write port allowing for parallel read and write access to a given data storage cell. In other embodiments, the data storage cells may include a single port through which a read or a write operation may be performed. It is noted that any suitable type of data storage cell may be employed. For example, in some embodiments, a Static Random Access Memory (SRAM) data storage cell may be employed. 
     During operation, Register File  302  may receive requests for read or write operations from both USMGR  303  as well as Datapath  301 . In some embodiments, accesses, both read and write, from Datapath  301  may take priority over accesses from USMGR  303 . 
     USMGR  303  includes write queues  305  and read queues  306  as well as additional control circuitry (not shown). In some embodiments, each write queue of write queues  305  may correspond to a respective bank of Register File  302 , and each read queue may correspond to a respective bank of Register File  302 . In other embodiments, each queue of write queues  305  and read queues  306  may store accesses for any bank of Register File  302 . Writes queues  305  and read queues  306  may include multiple registers (one register per entry in the queue), with each register including multiple data storage cells coupled in parallel. 
     During operation, USMGR  303  may receive read and write requests from Data Mover  304 . Each request may be targeted at a specific bank within Register File  302 . As described below in more detail, write requests may include control bits which may indicate that a given write request is to be held, i.e., not written to Register File  302 , in a write queue corresponding to the target bank in Register File  302 . USMGR  303  may also send encoded information on the status of write queues  305  and read queues  306 . Furthermore, USMGR  303  may also, in various embodiments, be configured to determine how often a given bank in Register File  302  is victimized, i.e., when USCPC accesses the given bank thereby preventing queue access to the given bank. As described in greater detail below, when a level of victimization meets or exceeds a threshold level, USMGR  303  may send a signal to USCPC  307  to hold further accesses, through Datapath  301 , to a victimized bank in Register File  302 . 
     Data Mover block  304  may include logic circuits and state machines collectively configured to receive and arbitrate requests from various agents within a graphics unit, such as, graphics unit  200  as illustrated in  FIG. 2 . For example, Data Mover block  304  may arbitrate requests from TPU  203  or PBE  205  as illustrated in  FIG. 2 . When arbitrate requests, Data Mover  304  may used queue status information received from USMGR  303  to select a next request to send to USMGR  303  for processing. Data Mover  304  may include control bits in write requests sent to USMGR  303  that indicate that data for a given write request may be needed shortly and should just be held in write queues  305 . 
     Data mover  304  may, in some embodiments, include format unit  309 . As described below in more detail, format unit  309  may, in various embodiments, be configured to receive data from a local memory and reformat or reorder the received data. Once the data has been reordered, it may be sent to USMGR  303  or other blocks within USC  300 . 
     USCPC  307  may also include assorted logic circuits and state machines configured to control operation of datapath  301  dependent upon instructions received from an instruction issue block. For example, USCPC  307  may receive instructions from Vertex Pipe  202  or Fragment Pipe  206 . USCPC  307  may receive one or more signals from USMGR  303  indicating that accesses, via datapath  301 , to a particular bank of Register File  302  should be halted. In some cases, accesses may be halted for multiple processing cycles, while USMGR  303  processes requests pending in write queues  305  and read queues  306 . Once USMGR  303  has determined the particular bank is no longer being victimized, USCPC  307  may resume allow datapath  301  to resume accesses to Register File  302 . 
     It is noted that the embodiment illustrated in  FIG. 3  is merely an example. In other embodiments, different functional blocks and different configurations of functional blocks are possible and contemplated. 
     Referring to  FIG. 4 , an embodiment of a format unit is illustrated. Format unit  400  may, in some embodiments, correspond to format unit  309  of USC  300  as illustrated in  FIG. 3 . In the illustrated embodiment, format unit  400  includes control queue  401  and data queue  402 . 
     Information received from memory may include both control information and graphics data, such as, e.g., pixel data. The control information may include information regarding any permutation of received graphics data. Such information may be used to properly format, i.e., write received graphics data into correct locations within data queue  402 . In various embodiments, control information may be stored in control queue  401 , separately from received graphics data. Control queue  401  may be coupled to incoming read information. One or more entries may be allocated when a read is issued, and may be de-allocated when the data arrives at data queue  402 . By storing control information separately from graphics data, control queue  401  may, in some embodiments, be scaled to handle read bandwidth requirements. 
     As described below in more detail, data queue  402  may be configured to receive incoming read data. Data queue  402  may include one or more selection circuits (also referred to herein as “alignment units”) that select and route specific bits of data from the memory to appropriate locations within data queue  402 . Once the data has stored, data queue  402  may send the data to an appropriate sub-block within a GPU, or any other suitable location. 
     Control queue  401  and data queue  402  may be designed in accordance with any one of various design styles. For example, in some embodiments, control queue  401  and data queue  402  may include multiple SRAM-style data storage cells. In other embodiments, control queue  401  and data queue  402  may include multiple registers or register files, each of which is configured to store a portion of data received from the memory. 
     It is noted that the embodiment illustrated in  FIG. 4  is merely an example. In other embodiments, different numbers of queues and different arrangements of queues are possible and contemplated. 
     Turning to  FIG. 5 , an embodiment of a data queue is illustrated. In some embodiments, data queue  500  may correspond to data queue  402  of format unit  400  as illustrated in  FIG. 4 . In the illustrated embodiment, data queue  500  includes storage array  501 , and alignment units (also referred to herein as “selection units”)  503  and  502 . Each of alignment units  503  and  502  are configured to receive data bus  504 . In some embodiments, data received via data bus  504  may be from a memory shared between multiple processing units. Data bus  504  may include multiple data bits. For example, in some embodiments, data bus  504  may include 128 data bits, or any other suitable number of data bits. 
     Each of alignment units  503  and  502  may be configured to selectively couple a portion of data bus  504  to column data lines  507  and row data lines  506 , respectively. In some embodiments, each of column lines  507  and row lines  506  may include less data bits than data bus  504 . The selection of which data bits of data bus  504  are coupled to column lines  507  and row lines  506  may, in various embodiments, depend upon control signal  505 . Although depicted as a single line, control signal  505  may include multiple data bits and may be encoded to reduce wiring overhead. Control signal  505  may, in some embodiments, be received from a control queue, such as, control queue  401  as illustrated in  FIG. 4 , for example. 
     Alignment units  503  and  502  may, in some embodiments, include one or more multiplex circuits, each of which is configured to select one data bit of data bus  504 . In some embodiments, multiple multiplex circuits may be coupled in parallel to select ranges of data bits from data  504  to be coupled to either row lines  506  or row lines  507 . Such multiplex circuits may be constructed in accordance with one of various design styles. For example, in some embodiments, the multiplex circuits may include a plurality of tri-state buffers whose outputs are coupled together in a wired-OR fashion, and whose control inputs are dependent upon one of the control signal  505 . In other embodiments, the multiplex circuits may include a plurality of logic gates configured to implement the desired multiplex. 
     Storage array  501  may include multiple data storage cells, registers, register files, or any suitable storage circuit. In some embodiments, each storage circuit included within storage array  501  may be a single-port storage circuit, while, in other embodiments, each storage circuit may include separate read and write ports. As described below in more detail, each data storage circuit may include a selection circuit configured to select one or more data lines from either row lines  506  or column lines  506  in response to one or more data bits from control signal  505 . Data stored in storage array  501  may be sent to various destinations, such as, e.g., registers within particular processing pipelines. 
     It is noted that the embodiment illustrated in  FIG. 5  is merely an example. In other embodiments, different functional units and different configurations of functional units may be employed. 
     Referring to  FIG. 6 , an embodiment of a storage array is illustrated. In some embodiments, storage array  600  may correspond to storage array  501  as illustrated in the embodiment depicted in  FIG. 5 . In the illustrated embodiment, storage array  600  includes storage units  601   a - c  and storage units  602   a - c . Storage unit  600  also includes row data lines  603   a - b , and column data lines  604   a - c , which may, in various embodiments, be coupled to alignment units such as, alignment units  502  and  503  as illustrated in  FIG. 5 , for example. It is noted that various control lines coupled to the individual storage units have been omitted for the sake of clarity. 
     Each storage units  601   a - c  and  602   a - c  is configured to receive data from either one or row data lines  603   a - b  or column data lines  604   a - c . For example, storage unit  601   a  may receive data from either column data line  604   a  or row data line  603   a . As described below, in more detail, each storage unit may include a multiplex circuit, or any other suitable selection circuit, configured to select one of the coupled row and column data lines. It is noted that although each row and column data lines are depicted as being a single line, in various embodiments, each of the illustrated row and column data lines may include multiple signal lines, each capable of carrying a single data bit. In such cases, each storage unit may include multiple storage circuits, each capable of storing a single data bit. 
     In various embodiments, the row data lines and the column data lines are orthogonal to each other in a physical design of storage array  600 . For example, row data line  603   a  is orthogonal to column data lines  604   a - c . The row data lines may, in some embodiments, be implemented on one metal layer of semiconductor manufacturing processing, while the column data lines may be implemented on another metal layer of the semiconductor manufacturing process. 
     During operation, data may be available on either row data lines  603   a - b  or column data lines  604   a - c  as determined by alignment units, such as alignment units  503  and  503  of  FIG. 5 , for example. Individual storage units may select data on its associated row or column data line for storage, thereby allowing data from various bit positions within data originally received by a format unit, to be selectively stored in different relative positions within storage array  600 . In some embodiments, data stored in each storage unit may be designated for a particular destination. For example, data stored in storage unit  601   a  may be designated to be sent to a register of an instance of a processing pipeline within a GPU, while data stored in storage unit  601   b  may be designated to be sent to a register in another instance of a processing pipeline with the GPU. By storing data in such a fashion, received data may be reordered or realigned to conform the a data format employed by a particular destination. 
     It is noted that the embodiment illustrated in  FIG. 6  is merely an example. In other embodiments different numbers of storage units, and different configurations of storage units are possible and contemplated. 
     Turning to  FIG. 7 , an embodiment of a storage unit is illustrated. In some embodiments, storage unit  700  may correspond to any or all of storage units  601   a - c  and  602   a - c  as illustrated in  FIG. 6 . In the illustrated embodiment, storage unit  700  includes storage cells  701  and multiplex circuit  702 . 
     Storage cells  701  may include multiple data storage circuits, each capable of storing a particular data bit. Although illustrated as a single unit, storage circuits  701  may, in various embodiments, include any suitable number of storage circuits. In such cases, multiplex output  706  may include multiple data lines, each of which may be coupled to a respective storage circuit of storage circuits  701 . 
     Multiplex circuit  702  may, in various embodiments, be configured to selectively couple either row line (also referred to herein as “row data line”)  703  or column line (also referred to herein as “column data line”)  704  to multiplex output  706  dependent upon a value of selection signal  705 . It is noted that although row line  703  and column line  704  are depicted as being a single data bit, in various embodiments, row line  703  and column lien  704  may include any suitable number of data bits. Such data bits may be a subset of row lines  506  or columns lines  507  as illustrated in  FIG. 5 . 
     In various embodiments, selection signal  705  may be received from a control queue such as, e.g., control queue  401  as illustrated in  FIG. 4 . Selection signal  705  may, in various embodiments, be the result of decoding control information received from the control queue. In other embodiments, control information may be decoded prior to storage in the control queue. 
     Storage cells  701  may include any suitable number of storage circuits. Such storage circuits may include a SRAM storage cell, a Dynamic RAM storage cell, a latch, a flip-flop circuit, or any other suitable storage circuit. In various embodiments, each storage circuit included in storage cells  701  may be read from or written to in parallel. 
     The embodiment illustrated in  FIG. 7  is merely an example. Different types of storage cells and multiplex circuits may be employed in various other embodiments. 
     Referring to  FIG. 8 , a flow diagram depicting an embodiment of a method for operating a format unit is illustrated. Referring collectively to the embodiment illustrated in  FIG. 4 , and the flow diagram of  FIG. 8 , the method begins in block  801 . 
     Control information and data may then be received (block  802 ). In various embodiments, the control information and data may be received from a local memory shared between different processing pipelines within a GPU. The control information may, in some embodiments, include information indicative of a destination for one or more portions of the received data. As described below, in more detail, the received data may need to be realigned (or “reformatted”) in order to match an alignment for a particular destination as indicated by the control information. It is noted that in some embodiments, the control information, for a given portion of data, may arrive prior to the data, while, in other embodiment, data and its accompanying control information may arrive together at format unit  400 . 
     The received control information may then be stored in control queue  401  (block  803 ). In various embodiments, the control information may be stored directly into control queue  401 . In other embodiments, the control information may be decoded, or otherwise processed, prior to storage. By storing the control information separately, a size of control queue  401  may be varied independently of a size of data queue  402  to accommodate changes in read bandwidth for a given GPU design. 
     The received data may then be formatted and stored in data queue  402  (block  804 ). As described below, in more detail, in regard to  FIG. 9 , a portion of the data may be sent to either row data lines or column data lines within data queue  402  dependent upon control information received from control queue  401  corresponding to the data being stored. Data storage units within data queue  402  may then select to receive data from either a row data line or column data line dependent upon the corresponding control information. By storing data in this fashion, the received data may be aligned (or “formatted”) to match an alignment of an intended recipient. For example, received data may be stored into multiple columns within a given row. Alternatively, the received data may be stored across multiple rows within a single column. 
     Once the data has been stored in data queue  402 , the data may be sent to its designated destination (block  805 ). In various embodiments, the destinations may include a register, or other suitable memory, within a particular processing pipeline within a GPU. In some embodiments, the stored data may be held in data queue  402  until the intended destination is ready to receive the data. The method may then conclude in block  806 . 
     It is noted that the embodiment of the method illustrated in  FIG. 8  is merely an example. In other embodiments, different operations, and different orders of operations may be employed. 
     Turning to  FIG. 9 , a flow diagram depicting an embodiment of a method for formatting data is illustrated. In various embodiments, the method illustrated in  FIG. 9  may correspond to the operation depicted in block  804  of the flow diagram illustrated in  FIG. 8 . Referring collectively to the embodiment illustrated in  FIG. 5  and the flow diagram of  FIG. 9 , the method begins in block  901 . 
     A row alignment may then be determined (block  902 ). In various embodiments, row alignment unit  502  may select a subset of data bits from data bus  504 . The selection may, in some embodiments, be dependent upon control signal  505 , which may, in other embodiments, be received from a control queue, such as, control queue  401  as illustrated in the embodiment of  FIG. 4 . The selected subset of data bits may then be coupled onto row data lines  506 . 
     A column alignment may then be determined (block  903 ). In various embodiments, column alignment unit  503  may select a subset of data bits from data bus  504 . The selection may, in some embodiments, be dependent upon control signal  505 , which may, in other embodiments, be received from a control queue, such as, control queue  401  as illustrated in the embodiment of  FIG. 4 . The selected subset of data bits may then be coupled onto column data lines  507 . It is noted that in some embodiments, either a row alignment, or a column alignment may be performed, while, in other embodiments, both a row and column alignment may be performed using different subsets of data bits from data bus  504 . 
     Once an alignment has been determined (either a row alignment, or a column alignment, or a combination, thereof), the alignment (or “formatted”) data may be stored in storage array  501  (block  904 ). As described above in regard to  FIG. 6 , storage array  501  may include multiple storage units, and, in some embodiments, data may only be stored in a subset of the storage units. Each storage unit may be configured to receive one or more data bits from either row data lines  506  or column data lines  507  dependent upon information encoded in control signal  505 . During a storage process, a given storage unit may store data received from either row data lines or column data lines. By allowing each storage unit to receive data in this fashion, routing congestion during physical design of format unit may be reduced in various embodiments. Once data is stored in the designated storage cells, the method may conclude in block  905 . 
     Although the operations illustrated in  FIG. 9  are depicted as being performed in a serial fashion, in other embodiments, one or more of the operations may be performed in parallel. 
     Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even where only a single embodiment is described with respect to a particular feature. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise. The above description is intended to cover such alternatives, modifications, and equivalents as would be apparent to a person skilled in the art having the benefit of this disclosure. 
     The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Accordingly, new claims may be formulated during prosecution of this application (or an application claiming priority thereto) to any such combination of features. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in the specific combinations enumerated in the appended claims.

Metadata:
Filing Date: 20140925
Publication Date: 20200908
Grant Date: 20200908
Priority Date: 20140925
Inventors: XIA, LIANG
KENNEY, ROBERT D.
GOODMAN, BENJIMAN L.
POTTER, TERENCE M.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F9/3012", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06T1/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06T1/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06T1/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06T1/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06T1/20", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 55584980