# vkCmdWriteTimestamp2(3) Manual Page

## Name

vkCmdWriteTimestamp2 - 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_3
    void vkCmdWriteTimestamp2(
        VkCommandBuffer                             commandBuffer,
        VkPipelineStageFlags2                       stage,
        VkQueryPool                                 queryPool,
        uint32_t                                    query);

or the equivalent command

    // Provided by VK_KHR_synchronization2
    void vkCmdWriteTimestamp2KHR(
        VkCommandBuffer                             commandBuffer,
        VkPipelineStageFlags2                       stage,
        VkQueryPool                                 queryPool,
        uint32_t                                    query);

## Parameters

- `commandBuffer` is the command buffer into which the command will be recorded.

- `stage` specifies 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 `vkCmdWriteTimestamp2` 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 `stage`.

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 `vkCmdWriteTimestamp2` 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-vkCmdWriteTimestamp2-stage-03929
  If the `geometryShader` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_GEOMETRY_SHADER_BIT`

- VUID-vkCmdWriteTimestamp2-stage-03930
  If the `tessellationShader` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_2_TESSELLATION_EVALUATION_SHADER_BIT`

- VUID-vkCmdWriteTimestamp2-stage-03931
  If the `conditionalRendering` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_CONDITIONAL_RENDERING_BIT_EXT`

- VUID-vkCmdWriteTimestamp2-stage-03932
  If the `fragmentDensityMap` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_FRAGMENT_DENSITY_PROCESS_BIT_EXT`

- VUID-vkCmdWriteTimestamp2-stage-03933
  If the `transformFeedback` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_TRANSFORM_FEEDBACK_BIT_EXT`

- VUID-vkCmdWriteTimestamp2-stage-03934
  If the `meshShader` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_MESH_SHADER_BIT_EXT`

- VUID-vkCmdWriteTimestamp2-stage-03935
  If the `taskShader` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_TASK_SHADER_BIT_EXT`

- VUID-vkCmdWriteTimestamp2-stage-07316
  If neither of the `shadingRateImage` or the `attachmentFragmentShadingRate` features are enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR`

- VUID-vkCmdWriteTimestamp2-stage-04957
  If the `subpassShading` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_SUBPASS_SHADER_BIT_HUAWEI`

- VUID-vkCmdWriteTimestamp2-stage-04995
  If the `invocationMask` feature is not enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_INVOCATION_MASK_BIT_HUAWEI`

- VUID-vkCmdWriteTimestamp2-stage-07946
  If neither the VK_NV_ray_tracing extension or the `rayTracingPipeline` feature are enabled, `stage` must not contain `VK_PIPELINE_STAGE_2_RAY_TRACING_SHADER_BIT_KHR`

- VUID-vkCmdWriteTimestamp2-synchronization2-03858
  The `synchronization2` feature must be enabled

- VUID-vkCmdWriteTimestamp2-stage-03859
  `stage` must only include a single pipeline stage

- VUID-vkCmdWriteTimestamp2-stage-03860
  `stage` must only include stages valid for the queue family that was used to create the command pool that `commandBuffer` was allocated from

- VUID-vkCmdWriteTimestamp2-queryPool-03861
  `queryPool` must have been created with a `queryType` of `VK_QUERY_TYPE_TIMESTAMP`

- VUID-vkCmdWriteTimestamp2-timestampValidBits-03863
  The command pool’s queue family must support a non-zero `timestampValidBits`

- VUID-vkCmdWriteTimestamp2-query-04903
  `query` must be less than the number of queries in `queryPool`

- VUID-vkCmdWriteTimestamp2-None-03864
  All queries used by the command must be unavailable

- VUID-vkCmdWriteTimestamp2-query-03865
  If `vkCmdWriteTimestamp2` 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-vkCmdWriteTimestamp2-commandBuffer-parameter
  `commandBuffer` must be a valid VkCommandBuffer handle

- VUID-vkCmdWriteTimestamp2-stage-parameter
  `stage` must be a valid combination of VkPipelineStageFlagBits2 values

- VUID-vkCmdWriteTimestamp2-queryPool-parameter
  `queryPool` must be a valid VkQueryPool handle

- VUID-vkCmdWriteTimestamp2-commandBuffer-recording
  `commandBuffer` must be in the recording state

- VUID-vkCmdWriteTimestamp2-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, compute, decode, or encode operations

- VUID-vkCmdWriteTimestamp2-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 | Action

## See Also

VK_KHR_synchronization2, VK_VERSION_1_3, VkCommandBuffer, VkPipelineStageFlags2, 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