# vkCmdWriteTimestamp(3) Manual Page

## Name

vkCmdWriteTimestamp - Write a device timestamp into a query object

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## 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 of the `shadingRateImage` or the `attachmentFragmentShadingRate` features 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 of the VK_NV_ray_tracing extension or the `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