C Specification

The set of supported time domains consists of:

// Provided by VK_EXT_calibrated_timestamps
typedef enum VkTimeDomainEXT {
    VK_TIME_DOMAIN_DEVICE_EXT = 0,
    VK_TIME_DOMAIN_CLOCK_MONOTONIC_EXT = 1,
    VK_TIME_DOMAIN_CLOCK_MONOTONIC_RAW_EXT = 2,
    VK_TIME_DOMAIN_QUERY_PERFORMANCE_COUNTER_EXT = 3,
} VkTimeDomainEXT;

Description

  • VK_TIME_DOMAIN_DEVICE_EXT specifies the device time domain. Timestamp values in this time domain use the same units and are comparable with device timestamp values captured using vkCmdWriteTimestamp or vkCmdWriteTimestamp2KHR and are defined to be incrementing according to the timestampPeriod of the device.

  • VK_TIME_DOMAIN_CLOCK_MONOTONIC_EXT specifies the CLOCK_MONOTONIC time domain available on POSIX platforms. Timestamp values in this time domain are in units of nanoseconds and are comparable with platform timestamp values captured using the POSIX clock_gettime API as computed by this example:

Note

An implementation supporting VK_EXT_calibrated_timestamps will use the same time domain for all its VkQueue so that timestamp values reported for VK_TIME_DOMAIN_DEVICE_EXT can be matched to any timestamp captured through vkCmdWriteTimestamp or vkCmdWriteTimestamp2KHR .

 
struct timespec tv;
clock_gettime(CLOCK_MONOTONIC, &tv);
return tv.tv_nsec + tv.tv_sec*1000000000ull;

  • VK_TIME_DOMAIN_CLOCK_MONOTONIC_RAW_EXT specifies the CLOCK_MONOTONIC_RAW time domain available on POSIX platforms. Timestamp values in this time domain are in units of nanoseconds and are comparable with platform timestamp values captured using the POSIX clock_gettime API as computed by this example:

struct timespec tv;
clock_gettime(CLOCK_MONOTONIC_RAW, &tv);
return tv.tv_nsec + tv.tv_sec*1000000000ull;

  • VK_TIME_DOMAIN_QUERY_PERFORMANCE_COUNTER_EXT specifies the performance counter (QPC) time domain available on Windows. Timestamp values in this time domain are in the same units as those provided by the Windows QueryPerformanceCounter API and are comparable with platform timestamp values captured using that API as computed by this example:

LARGE_INTEGER counter;
QueryPerformanceCounter(&counter);
return counter.QuadPart;

See Also

VK_EXT_calibrated_timestamps, VkCalibratedTimestampInfoEXT, vkGetPhysicalDeviceCalibrateableTimeDomainsEXT

Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0