1// Copyright 2017-2022 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 requires 15 {spirv}/KHR/SPV_KHR_shader_clock.html[`SPV_KHR_shader_clock`]. 16 - This extension provides API support for 17 {GLregistry}/ARB/ARB_shader_clock.txt[`ARB_shader_clock`] and 18 {GLSLregistry}/ext/GL_EXT_shader_realtime_clock.txt[`EXT_shader_realtime_clock`] 19*Contributors*:: 20 - Aaron Hagan, AMD 21 - Daniel Koch, NVIDIA 22 23=== Description 24 25This extension advertises the SPIR-V code:ShaderClockKHR capability for 26Vulkan, which allows a shader to query a real-time or monotonically 27incrementing counter at the subgroup level or across the device level. 28The two valid SPIR-V scopes for code:OpReadClockKHR are code:Subgroup and 29code:Device. 30 31When using GLSL source-based shading languages, the code:clockRealtime*EXT() 32timing functions map to the code:OpReadClockKHR instruction with a scope of 33code:Device, and the code:clock*ARB() timing functions map to the 34code:OpReadClockKHR instruction with a scope of code:Subgroup. 35 36include::{generated}/interfaces/VK_KHR_shader_clock.adoc[] 37 38=== New SPIR-V Capabilities 39 40 * <<spirvenv-capabilities-table-ShaderClockKHR, code:ShaderClockKHR>> 41 42=== Version History 43 44 * Revision 1, 2019-4-25 (Aaron Hagan) 45 ** Initial revision 46