1// Copyright 2017-2024 The Khronos Group Inc. 2// 3// SPDX-License-Identifier: CC-BY-4.0 4 5include::{generated}/meta/{refprefix}VK_KHR_shader_clock.adoc[] 6 7=== Other Extension Metadata 8 9*Last Modified Date*:: 10 2019-4-25 11*IP Status*:: 12 No known IP claims. 13*Interactions and External Dependencies*:: 14 - This extension provides API support for 15 {GLregistry}/ARB/ARB_shader_clock.txt[`GL_ARB_shader_clock`] and 16 {GLSLregistry}/ext/GL_EXT_shader_realtime_clock.txt[`GL_EXT_shader_realtime_clock`] 17*Contributors*:: 18 - Aaron Hagan, AMD 19 - Daniel Koch, NVIDIA 20 21=== Description 22 23This extension advertises the SPIR-V code:ShaderClockKHR capability for 24Vulkan, which allows a shader to query a real-time or monotonically 25incrementing counter at the subgroup level or across the device level. 26The two valid SPIR-V scopes for code:OpReadClockKHR are code:Subgroup and 27code:Device. 28 29When using GLSL source-based shading languages, the code:clockRealtime*EXT() 30timing functions map to the code:OpReadClockKHR instruction with a scope of 31code:Device, and the code:clock*ARB() timing functions map to the 32code:OpReadClockKHR instruction with a scope of code:Subgroup. 33 34include::{generated}/interfaces/VK_KHR_shader_clock.adoc[] 35 36=== New SPIR-V Capabilities 37 38 * <<spirvenv-capabilities-table-ShaderClockKHR, code:ShaderClockKHR>> 39 40=== Version History 41 42 * Revision 1, 2019-4-25 (Aaron Hagan) 43 ** Initial revision 44