Computing system capable of parallelizing the operation of multiple graphics processing pipelines (GPPLS)

• US 20090179894A1
• Filed: 08/29/2008
• Published: 07/16/2009
• Est. Priority Date: 11/19/2003
• Status: Abandoned Application

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Bakalash, Reuven, Leviathan, Yaniv
• Application Number:
  US12/231,296
• Publication Number:
  US 20090179894A1
• Time in Patent Office: Days
• US Class Current: 345/422
• CPC Class Codes: G06F 2209/501 Performance criteria
• CPC Class Codes: G06F 9/5044 considering hardware capabilities
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: G06T 15/005 General purpose rendering architectures
• CPC Class Codes: G06T 2210/52 Parallel processing
• CPC Class Codes: G09G 5/14 Display of multiple viewports
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/397 Arrangements specially adapted for transferring the contents of two or more bit-mapped memories to the screen simultaneously, e.g. for mixing or overlay G09G5/02 takes precedence

Abstract

A computing system capable of parallelizing the operation of multiple graphics processing pipelines (GPPLs), and including one or more CPUs, in communication with a memory space, and a parallel graphics processing subsystem (PGPS) supporting an object-division mode of parallel operation including at least four stages, namely, decomposition, distribution, rendering and recomposition. The PGPS includes a plurality of graphic processing pipelines (GPPLs), wherein each GPPL includes a color frame buffer and Z depth buffer. Within each GPPL, a partial complementary-type color image of the 3D scene is rendered and buffered in its color frame buffer. A complete color image of the 3D scene is recomposited by (i) merging the partial complementary-type color images within the GPPLs using a depthless method of image recomposition not involving the comparison of depth values stored in the Z depth buffers, and (ii) buffering the complete color image in the color frame buffer of the primary GPPL for display on a display device.

Claims

1. A computing system capable of parallelizing the operation of multiple graphics processing pipelines (GPPLs), said computing system comprising:

memory space for storing one or more graphics-based applications, and a graphics library for generating a stream of graphics commands and data (GCAD) during the execution of the graphics-based applications;

one or more CPUs, in communication with said memory space, for (i) executing said graphics-based applications, (ii) generating said stream of graphics commands and data, and (iii) segmenting said stream of graphics commands into frames for rendering pixel-based images of a 3D scene generated by at least one said graphics-based application, and wherein objects within said 3D scene are generated by processing said frames of graphics commands and data along said stream; and

a parallel graphics processing subsystem (PGPS) supporting an object-division mode of parallel operation including at least four stages, namely, decomposition, distribution, rendering and recomposition;

wherein said PGPS includes;

(i) a plurality of graphic processing pipelines (GPPLs), including a primary GPPL, wherein each said GPPL includes a color frame buffer and Z depth buffer; and

(ii) a parallel mode control module (PMCM) for automatically controlling said object-division mode of parallel operation during the run-time of said graphics-based application, during which said GPPLs are driven in a parallelized manner and performing the following graphics processing operations;

(i) decomposing objects in each frame of said stream of graphics commands and data, assigning the objects to particular GPPLs for use in rendering operations;

(ii) distributing objects to said GPPLs;

(iii) rendering a partial complementary-type color image of the 3D scene within each GPPL, and buffering the partial complementary-type color image within the color frame buffer in said GPPL; and

(iv) recompositing a complete color image of the 3D scene, by merging the partial complementary-type color images within said GPPLs employing a depthless method of image recomposition not involving the comparison of depth values stored in said Z depth buffers, and buffering said complete color image in the color frame buffer of said primary GPPL for display on a display device.

2. The computing system of claim 1, wherein said PGPS further includes:

(i) a decomposition module for supporting the decomposition stage of parallel operation;

(ii) a distribution module for supporting the distribution stage of parallel operation;

(iii) a recomposition module for supporting the recomposition stage of parallel operation; and

(iv) a rendering module for supporting the rendering stage of parallel operation.

4. The computing system of claim 1, wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting (1) a geometry subsystem having an input assembler and a vertex shader, (2) a set up engine, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers.

5. The computing system of claim 1, wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting (1) a geometry subsystem having an input assembler, a vertex shader and a geometry shader, (2) a rasterizer, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers.

6. The computing system of claim 1, wherein each said GPPL is a CPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer including stencil, depth and color buffers, and (ii) a graphics processing pipeline realized by a cell of a multi-core CPU chip, including a plurality of in-order SIMD processors, and optionally, a GPPL-specific extension, namely, a texture sampler that loads texture maps from memory, filters them for level-of-detail, and feeds to pixel processing portion of the pipeline.

9. The computing system of claim 2 wherein said graphics data includes data selected from the group consisting of FB data, commands, textures, geometric data and other data.

10. The computing system of claim 2, wherein said recomposition module supports a variety of modes the merging of partial complementary-type images in the color frame buffers of said GPPLs.

11. The computing system of claim 2, wherein said variety of modes of merging said partial complementary-type images includes:

merging color frame buffers without z buffers, and merging color buffers using stencil-assisted processing.

3. The computing system of claim 3, wherein during operation,

(i) said decomposition module divides the stream of graphic commands and data (GCAD) according to said object-division mode of parallel operation;

(ii) said distribution module distributes graphic commands and data (to said GPPLs;

(iii) said rendering module generates complementary-type partial color images according to a parallel multi-pass graphics processing method; and

(iv) said recomposition module uses inter-GPU communication to transfer the pixel data of said complementary-type partial images among said GPPLs, and a depthless image merging process to generate said complete color image of the 3D scene for display on said display device.

7. The computing system of claim 3, wherein the decomposition module supports the scanning of commands, the control of commands, the tracking of objects, the balancing of loads, and the assignment of objects to said GPPLs,

8. The computing system of claim 3, wherein said distribution module supports transmission of graphics data in various modes including CPU-to/from-GPPL, inter-GPPL, broadcast, hub-to/from-CPU, and hub-to/from-CPU and hub-to/from-GPPL.

12. A parallel graphics processing system (PGPS) for embodying in a PC-based host computing system, and supporting an object-division mode of parallel operation including at least four stages, namely, decomposition, distribution, rendering and recomposition, said PGPS comprising:

a plurality of graphic processing pipelines (GPPLs), including a primary GPPL, wherein each said GPPL includes a color frame buffer and Z depth buffer; and

a parallel mode control module (PMCM) for automatically controlling said object-division mode of parallel operation during the run-time of said graphics-based application, during which said GPPLs are driven in a parallelized manner and performing the following graphics processing operations;

(i) decomposing objects in each frame of said stream of graphics commands and data, assigning the objects to particular GPPLs for use in rendering operations;

(ii) distributing objects to said GPPLs;

(iii) rendering a partial complementary-type color image of the 3D scene within each GPPL, and buffering the partial complementary-type color image within the color frame buffer in said GPPL; and

(iv) recompositing a complete color image of the 3D scene, by merging the partial complementary-type color images within said GPPLs employing a depthless method of image recomposition not involving the comparison of depth values stored in said Z depth buffers, and buffering said complete color image in the color frame buffer of said primary GPPL for display on a display device.

13. The parallel graphics processing system of claim 12, which further includes:

(i) a decomposition module for supporting the decomposition stage of parallel operation;

(ii) a distribution module for supporting the distribution stage of parallel operation;

(iii) a recomposition module for supporting the recomposition stage of parallel operation; and

(iv) a rendering module for supporting the rendering stage of parallel operation.

14. The parallel graphics processing system of claim 13, wherein said decomposition module and distribution module resides as a software package in said memory space;

and said GPPLs on said external graphics cards are (i) connected to said bridge circuit, (ii) implement said rendering and recomposition modules, and (iii) driven in a parallelized manner under the control of said PMCM.

15. The parallel graphics processing system of claim 13, wherein during operation,

(i) said decomposition module divides the stream of graphic commands and data (GCAD) according to said object-division mode of parallel operation;

(ii) said distribution module uses said bridge circuit to distribute graphic commands and data to said GPPLs;

(iii) said rendering module generates complementary-type partial color images according to a parallel multi-pass graphics processing method; and

(iv) said recomposition module uses inter-GPU communication to transfer the pixel data of said complementary-type partial images among said GPPLs, and a depthless image merging process to generate a complete color image of the 3D scene for display on said display device.

16. The parallel graphics processing system of claim 12, wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting (1) a geometry subsystem having an input assembler and a vertex shader, (2) a set up engine, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers.

17. The parallel graphics processing system of claim 12, wherein each said GPPL is a GPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer (FB) including stencil, depth and color buffers, and (ii) a graphics processing unit (GPU) supporting (1) a geometry subsystem having an input assembler, a vertex shader and a geometry shader, (2) a rasterizer, and (3) a pixel subsystem including a pixel shader receiving pixel data from the frame buffer and a raster operators operating on pixel data in the frame buffers.

18. The parallel graphics processing system of claim 12, wherein each said GPPL is a CPU-based graphics processing pipeline which comprises (i) a video memory structure supporting a frame buffer including stencil, depth and color buffers, and (ii) a graphics processing pipeline realized by one cell of a multi-core CPU chip, consisting of 16 in-order SIMD processors, and further including a GPU-specific extension, namely, a texture sampler that loads texture maps from memory, filters them for level-of-detail, and feeds to pixel processing portion of the pipeline.

19. The parallel graphics processing system of claim 13, wherein the decomposition module supports the scanning of commands, the control of commands, the tracking of objects, the balancing of loads, and the assignment of objects to said GPPLs,

20. The parallel graphics processing system of claim 13, wherein said distribution module supports transmission of graphics data in various modes including CPU-to/from-GPPL, inter-GPPL, broadcast, hub-to/from-CPU, and hub-to/from-CPU and hub-to/from-GPPL.

21. The parallel graphics processing system of claim 12, wherein said graphics data includes data selected from the group consisting of FB data, commands, textures, geometric data and other data.

22. The parallel graphics processing system of claim 13, wherein said recomposition module supports a variety of modes the merging of partial complementary-type images in the color frame buffers of said GPPLs.

23. The parallel graphics processing system of claim 12, wherein said variety of modes of merging said partial complementary-type images includes:

merging color frame buffers without z buffers, and merging color buffers using stencil-assisted processing.