C Specification

To request a timestamp and write the value to memory, call:

// Provided by VK_VERSION_1_0
void vkCmdWriteTimestamp(
    VkCommandBuffer                             commandBuffer,
    VkPipelineStageFlagBits                     pipelineStage,
    VkQueryPool                                 queryPool,
    uint32_t                                    query);

Parameters

  • commandBuffer is the command buffer into which the command will be recorded.

  • pipelineStage is a VkPipelineStageFlagBits value, specifying a stage of the pipeline.

  • queryPool is the query pool that will manage the timestamp.

  • query is the query within the query pool that will contain the timestamp.

Description

When vkCmdWriteTimestamp is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and writes a timestamp to a query pool.

The first synchronization scope includes all commands that occur earlier in submission order. The synchronization scope is limited to operations on the pipeline stage specified by pipelineStage.

The second synchronization scope includes only the timestamp write operation.

Note

Implementations may write the timestamp at any stage that is logically later than stage.

Any timestamp write that happens-after another timestamp write in the same submission must not have a lower value unless its value overflows the maximum supported integer bit width of the query. If VK_KHR_calibrated_timestamps or VK_EXT_calibrated_timestamps is enabled, this extends to timestamp writes across all submissions on the same logical device: any timestamp write that happens-after another must not have a lower value unless its value overflows the maximum supported integer bit width of the query. Timestamps written by this command must be in the VK_TIME_DOMAIN_DEVICE_KHR time domain. If an overflow occurs, the timestamp value must wrap back to zero.

Note

Comparisons between timestamps should be done between timestamps where they are guaranteed to not decrease. For example, subtracting an older timestamp from a newer one to determine the execution time of a sequence of commands is only a reliable measurement if the two timestamp writes were performed in the same submission, or if the writes were performed on the same logical device and VK_KHR_calibrated_timestamps or VK_EXT_calibrated_timestamps is enabled.

If vkCmdWriteTimestamp is called while executing a render pass instance that has multiview enabled, the timestamp uses N consecutive query indices in the query pool (starting at query) where N is the number of bits set in the view mask of the subpass the command is executed in. The resulting query values are determined by an implementation-dependent choice of one of the following behaviors:

  • The first query is a timestamp value and (if more than one bit is set in the view mask) zero is written to the remaining queries. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the difference between the first query written by each command.

  • All N queries are timestamp values. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the sum of the difference between corresponding queries written by each command. The difference between corresponding queries may be the execution time of a single view.

In either case, the application can sum the differences between all N queries to determine the total execution time.

Valid Usage

  • VUID-vkCmdWriteTimestamp-pipelineStage-04074
    pipelineStage must be a valid stage for the queue family that was used to create the command pool that commandBuffer was allocated from

  • VUID-vkCmdWriteTimestamp-pipelineStage-04075
    If the geometryShader feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT

  • VUID-vkCmdWriteTimestamp-pipelineStage-04076
    If the tessellationShader feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT or VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT

  • VUID-vkCmdWriteTimestamp-pipelineStage-04077
    If the conditionalRendering feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT

  • VUID-vkCmdWriteTimestamp-pipelineStage-04078
    If the fragmentDensityMap feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT

  • VUID-vkCmdWriteTimestamp-pipelineStage-04079
    If the transformFeedback feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT

  • VUID-vkCmdWriteTimestamp-pipelineStage-04080
    If the meshShader feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_MESH_SHADER_BIT_EXT

  • VUID-vkCmdWriteTimestamp-pipelineStage-07077
    If the taskShader feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_TASK_SHADER_BIT_EXT

  • VUID-vkCmdWriteTimestamp-shadingRateImage-07314
    If neither the shadingRateImage or attachmentFragmentShadingRate are enabled, pipelineStage must not be VK_PIPELINE_STAGE_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR

  • VUID-vkCmdWriteTimestamp-synchronization2-06489
    If the synchronization2 feature is not enabled, pipelineStage must not be VK_PIPELINE_STAGE_NONE

  • VUID-vkCmdWriteTimestamp-rayTracingPipeline-07943
    If neither the VK_NV_ray_tracing extension or rayTracingPipeline feature are enabled, pipelineStage must not be VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR

  • VUID-vkCmdWriteTimestamp-queryPool-01416
    queryPool must have been created with a queryType of VK_QUERY_TYPE_TIMESTAMP

  • VUID-vkCmdWriteTimestamp-timestampValidBits-00829
    The command pool’s queue family must support a non-zero timestampValidBits

  • VUID-vkCmdWriteTimestamp-query-04904
    query must be less than the number of queries in queryPool

  • VUID-vkCmdWriteTimestamp-None-00830
    All queries used by the command must be unavailable

  • VUID-vkCmdWriteTimestamp-query-00831
    If vkCmdWriteTimestamp is called within a render pass instance, the sum of query and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in queryPool

Valid Usage (Implicit)

  • VUID-vkCmdWriteTimestamp-commandBuffer-parameter
    commandBuffer must be a valid VkCommandBuffer handle

  • VUID-vkCmdWriteTimestamp-pipelineStage-parameter
    pipelineStage must be a valid VkPipelineStageFlagBits value

  • VUID-vkCmdWriteTimestamp-queryPool-parameter
    queryPool must be a valid VkQueryPool handle

  • VUID-vkCmdWriteTimestamp-commandBuffer-recording
    commandBuffer must be in the recording state

  • VUID-vkCmdWriteTimestamp-commandBuffer-cmdpool
    The VkCommandPool that commandBuffer was allocated from must support transfer, graphics, compute, decode, encode, or optical flow operations

  • VUID-vkCmdWriteTimestamp-commonparent
    Both of commandBuffer, and queryPool must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

  • Host access to commandBuffer must be externally synchronized

  • Host access to the VkCommandPool that commandBuffer was allocated from must be externally synchronized

Command Properties
Command Buffer Levels Render Pass Scope Video Coding Scope Supported Queue Types Command Type

Primary
Secondary

Both

Both

Transfer
Graphics
Compute
Decode
Encode
Opticalflow

Action

See Also

VK_VERSION_1_0, VkCommandBuffer, VkPipelineStageFlagBits, VkQueryPool

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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0