vkCmdWriteTimestamp2(3)

Name

vkCmdWriteTimestamp2 - Write a device timestamp into a query object

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);
// Provided by VK_KHR_synchronization2
// Equivalent to vkCmdWriteTimestamp2
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.

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.

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 or dynamic render pass 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.

  • All N queries are timestamp values.

Either way, if two timestamps are written in the same subpass or dynamic render pass with multiview enabled, each of the N consecutive queries written for a timestamp must not have a lower value than the queries with corresponding indices written by the timestamp that happens-before unless the value overflows the maximum supported integer bit width of the query.

Valid Usage
Valid Usage (Implicit)
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

VK_QUEUE_COMPUTE_BIT
VK_QUEUE_GRAPHICS_BIT
VK_QUEUE_TRANSFER_BIT
VK_QUEUE_VIDEO_DECODE_BIT_KHR
VK_QUEUE_VIDEO_ENCODE_BIT_KHR

Action
Conditional Rendering

vkCmdWriteTimestamp2 is not affected by conditional rendering

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.