| Name |
| |
| KHR_parallel_shader_compile |
| |
| Name Strings |
| |
| GL_KHR_parallel_shader_compile |
| |
| Contact |
| |
| Geoff Lang, (geofflang 'at' google.com) |
| |
| Contributors |
| |
| Timothy Lottes, AMD |
| Graham Sellers, AMD |
| Eric Werness, NVIDIA |
| Geoff Lang, Google |
| Daniel Koch, NVIDIA |
| |
| Notice |
| |
| Copyright (c) 2015 The Khronos Group Inc. Copyright terms at |
| http://www.khronos.org/registry/speccopyright.html |
| |
| Status |
| |
| Complete |
| |
| Version |
| |
| Last Modified Date: 2017-04-24 |
| Revision: 2 |
| |
| Number |
| |
| ARB Extension #192 |
| OpenGL ES Extension #288 |
| |
| Dependencies |
| |
| This extension is written against OpenGL 4.5 (CoreProfile) dated |
| May 28 2015. |
| |
| OpenGL ES 2.0 is required (for mobile). |
| |
| 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 MaxShaderCompilerThreadsKHR(uint count); |
| |
| New Tokens |
| |
| Accepted by the <pname> parameter of GetBooleanv, GetIntegerv, |
| GetInteger64v, GetFloatv, and GetDoublev: |
| |
| MAX_SHADER_COMPILER_THREADS_KHR 0x91B0 |
| |
| Accepted as part of the <pname> parameter to GetShaderiv and |
| accepted as part of the <pname> parameter to GetProgramiv: |
| |
| COMPLETION_STATUS_KHR 0x91B1 |
| |
| IP Status |
| |
| None. |
| |
| Additions to Chapter 7 "Programs and Shaders", |
| |
| Append to the end of 7.1 "Shader Objects", |
| |
| Applications 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 MaxShaderCompilerThreadsKHR(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 MaxShaderCompilerThreadsKHR <count> |
| by calling GetIntegerv with <pname> set to MAX_SHADER_COMPILER_THREADS_KHR, |
| which returns the value of the current state (Table 23.51). |
| |
| |
| Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the |
| descriptions for "pname" for "GetShaderiv", |
| |
| If <pname> is COMPLETION_STATUS_KHR, TRUE is returned if the shader |
| compilation has completed, FALSE otherwise. |
| |
| Add to 7.13 "Shader, Program, and Program Pipeline Queries" under the |
| descriptions for "pname" for "GetProgramiv", |
| |
| If <pname> is COMPLETION_STATUS_KHR, TRUE is returned if the program |
| linking has completed, FALSE otherwise. |
| |
| New State |
| |
| Add to Table 23.51: Hints |
| Get Value Type Get Command Initial Value Description Sec |
| ------------------------------- ---- ------------ ------------- -------------------- ---- |
| MAX_SHADER_COMPILER_THREADS_KHR 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_KHR B GetProgramiv TRUE Program linking has 7.13 |
| completed |
| |
| Add to Table 23.30: Shader Object State |
| Get Value Type Get Command Initial Value Description Sec |
| --------------------- ---- ------------ ------------- -------------------- ---- |
| COMPLETION_STATUS_KHR B GetShaderiv TRUE Shader compilation 7.13 |
| has completed |
| |
| Interactions with OpenGL ES |
| |
| If implemented in OpenGL ES ignore all references to GetDoublev. |
| |
| If the supported ES version is less than 3.0, ignore all references to |
| GetInteger64v. |
| |
| 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 implementation-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. |
| |
| 3) Does glGetIntegerv(MAX_SHADER_COMPILER_THREADS_KHR) just return the |
| value set by MaxShaderCompilerThreadsKHR? Or, if the state is 0xFFFFFFFF |
| ("do something implementation specific"), does it return the number of |
| threads the implementation has actually chosen to use? |
| |
| RESOLVED: As with other state queries, this returns the value that was last |
| set, or if no value was set by the application it returns the default state |
| value (0xFFFFFFFF). |
| |
| Revision History |
| |
| Rev Date Author Changes |
| --- ---------- -------- --------------------------------------------- |
| 1 2017-03-23 glang Cast as KHR based on v6 of |
| ARB_parallel_shader_compile. |
| 2 2017-04-24 dgkoch Spec clarifications, add issue 3. |
