| Name |
| |
| ARB_parallel_shader_compile |
| |
| Name Strings |
| |
| GL_ARB_parallel_shader_compile |
| |
| Contact |
| |
| Timothy Lottes (timothy.lottes 'at' amd.com) |
| |
| Contributors |
| |
| Timothy Lottes, AMD |
| Graham Sellers, AMD |
| Eric Werness, NVIDIA |
| |
| Notice |
| |
| Copyright (c) 2015 The Khronos Group Inc. Copyright terms at |
| http://www.khronos.org/registry/speccopyright.html |
| |
| Status |
| |
| Complete. Approved by the ARB on June 26, 2015. |
| Ratified by the Khronos Board of Promoters on August 7, 2015. |
| |
| Version |
| |
| Last Modified Date: 09/01/2015 |
| Revision: 6 |
| |
| Number |
| |
| ARB Extension #179 |
| |
| Dependencies |
| |
| This extension is written against OpenGL 4.5 (CoreProfile) dated |
| May 28 2015. |
| |
| Overview |
| |
| Compiling GLSL into implementation-specific code can be a time consuming |
| process, so a GL implementation may wish to perform the compilation in a |
| separate CPU thread. This extension provides a mechanism for the application |
| to provide a hint to limit the number of threads it wants to be used to |
| compile shaders, as well as a query to determine if the compilation process |
| is complete. |
| |
| New Procedures and Functions |
| |
| void MaxShaderCompilerThreadsARB(uint count); |
| |
| New Tokens |
| |
| Accepted by the <pname> parameter of GetBooleanv, GetIntegerv, |
| GetInteger64v, GetFloatv, and GetDoublev: |
| |
| MAX_SHADER_COMPILER_THREADS_ARB 0x91B0 |
| |
| Accepted as part of the <pname> parameter to GetShaderiv() and |
| accepted as part of the <pname> parameter to GetProgramiv(): |
| |
| COMPLETION_STATUS_ARB 0x91B1 |
| |
| IP Status |
| |
| None. |
| |
| Additions to Chapter 7 "Programs and Shaders", |
| |
| Append to the end of 7.1 "Shader Objects", |
| |
| Application may use the following to hint to the driver the maximum |
| number background threads it would like to be used in the process of |
| compiling shaders or linking programs, |
| |
| void MaxShaderCompilerThreadsARB(uint count); |
| |
| where <count> is the number of background threads. A <count> of zero |
| specifies a request for no parallel compiling or linking and a <count> of |
| 0xFFFFFFFF requests an implementation-specific maximum. |
| |
| An implementation may combine the maximum compiler thread request from |
| multiple contexts in a share group in an implementation-specific way. |
| |
| An application can query the current MaxShaderCompilerThreads() <count> |
| by calling GetIntegerv with <pname> set to MAX_SHADER_COMPILER_THREADS. |
| |
| |
| Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the |
| descriptions for "pname" for "GetShaderiv()", |
| |
| If <pname> is COMPLETION_STATUS, FALSE is returned if the shader is |
| currently being compiled by a background thread, TRUE otherwise. |
| |
| Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the |
| descriptions for "pname" for "GetProgramiv()", |
| |
| If <pname> is COMPLETION_STATUS, FALSE is returned if the program is |
| currently being linked by a background thread, TRUE otherwise. |
| |
| New State |
| |
| Add to Table 23.51: Hints |
| Get Value Type Get Command Initial Value Description Sec |
| --------------------------- ---- ------------ ------------- -------------------- ---- |
| MAX_SHADER_COMPILER_THREADS_ARB Z+ GetIntegerv 0xFFFFFFFF Max compile threads 7.13 |
| |
| Add to Table 23.32: Program Object State |
| Get Value Type Get Command Initial Value Description Sec |
| --------------------------- ---- ------------ ------------- -------------------- ---- |
| COMPLETION_STATUS_ARB B GetProgramiv TRUE Program is not being 7.13 |
| compiled in parallel |
| |
| Add to Table 23.30: Shader Object State |
| Get Value Type Get Command Initial Value Description Sec |
| --------------------------- ---- ------------ ------------- -------------------- ---- |
| COMPLETION_STATUS_ARB B GetShaderiv TRUE Shader is not being 7.13 |
| linked in parallel |
| Issues |
| |
| 1) Where should the hint state be stored? |
| |
| UNRESOLVED: Each context has its own value which may be specified and |
| queried, but an implementation may choose to combine the hints from multiple |
| contexts in an implmentation-specific manner. There isn't really any |
| precedent for per-share group state. |
| |
| 2) Can we make the requirements more strict? |
| |
| RESOLVED: We could, but making sure all of the error behavior is correct and |
| fully specified would likely take more time than we have. This spec allows |
| an application to clearly request its intent even if there aren't guarantees |
| that the implementation will exactly obey the request. |
| |
| Revision History |
| |
| Rev Date Author Changes |
| --- ---------- -------- --------------------------------------------- |
| 1 03/22/2015 tlottes Initial revision |
| 2 03/23/2015 tlottes Added way to get MAX_SHADER_COMPILER_THREADS |
| 3 04/20/2015 tlottes Updated tokens and functions |
| 4 06/18/2015 tlottes Added New State, noted per context, issues |
| 5 06/23/2015 ewerness Clarify the spec is a hint, other language fixes |
| 6 09/01/2015 pdaniell Fix the functions that can be used to query |
| MAX_SHADER_COMPILER_THREADS_ARB. |
