Deprecation state
-
Promoted to Vulkan 1.3
Contact
-
Tobias Hector tobski
Other Extension Metadata
- Last Modified Date
-
2020-12-03
- Interactions and External Dependencies
-
-
Promoted to Vulkan 1.3 Core
-
Interacts with
VK_KHR_create_renderpass2
-
- Contributors
-
-
Tobias Hector
-
Description
This extension modifies the original core synchronization APIs to simplify the interface and improve usability of these APIs. It also adds new pipeline stage and access flag types that extend into the 64-bit range, as we have run out within the 32-bit range. The new flags are identical to the old values within the 32-bit range, with new stages and bits beyond that.
Pipeline stages and access flags are now specified together in memory
barrier structures, making the connection between the two more obvious.
Additionally, scoping the pipeline stages into the barrier structs allows
the use of the MEMORY_READ
and MEMORY_WRITE
flags without
sacrificing precision.
The per-stage access flags should be used to disambiguate specific accesses
in a given stage or set of stages - for instance, between uniform reads and
sampling operations.
Layout transitions have been simplified as well; rather than requiring a
different set of layouts for depth/stencil/color attachments, there are
generic VK_IMAGE_LAYOUT_ATTACHMENT_OPTIMAL_KHR
and
VK_IMAGE_LAYOUT_READ_ONLY_OPTIMAL_KHR
layouts which are contextually
applied based on the image format.
For example, for a depth format image,
VK_IMAGE_LAYOUT_READ_ONLY_OPTIMAL_KHR
is equivalent to
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL_KHR
.
VK_IMAGE_LAYOUT_READ_ONLY_OPTIMAL_KHR
also functionally replaces
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL
.
Events are now more efficient, because they include memory dependency information when you set them on the device. Previously, this information was only known when waiting on an event, so the dependencies could not be satisfied until the wait occurred. That sometimes meant stalling the pipeline when the wait occurred. The new API provides enough information for implementations to satisfy these dependencies in parallel with other tasks.
Queue submission has been changed to wrap command buffers and semaphores in
extensible structures, which incorporate changes from Vulkan 1.1,
VK_KHR_device_group
, and VK_KHR_timeline_semaphore
.
This also adds a pipeline stage to the semaphore signal operation, mirroring
the existing pipeline stage specification for wait operations.
Other miscellaneous changes include:
-
Events can now be specified as interacting only with the device, allowing more efficient access to the underlying object.
-
Image memory barriers that do not perform an image layout transition can be specified by setting
oldLayout
equal tonewLayout
.-
E.g. the old and new layout can both be set to
VK_IMAGE_LAYOUT_UNDEFINED
, without discarding data in the image.
-
-
Queue family ownership transfer parameters are simplified in some cases.
-
Where two synchronization commands need to be matched up (queue transfer operations, events), the dependency information specified in each place must now match completely for consistency.
-
Extensions with commands or functions with a VkPipelineStageFlags or VkPipelineStageFlagBits parameter have had those APIs replaced with equivalents using VkPipelineStageFlags2KHR.
-
The new event and barrier interfaces are now more extensible for future changes.
-
Relevant pipeline stage masks can now be specified as empty with the new
VK_PIPELINE_STAGE_NONE_KHR
andVK_PIPELINE_STAGE_2_NONE_KHR
values. -
VkMemoryBarrier2KHR can be chained to VkSubpassDependency2, overriding the original 32-bit stage and access masks.
New Structures
If VK_NV_device_diagnostic_checkpoints is supported:
New Enum Constants
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VK_KHR_SYNCHRONIZATION_2_EXTENSION_NAME
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VK_KHR_SYNCHRONIZATION_2_SPEC_VERSION
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Extending VkAccessFlagBits:
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VK_ACCESS_NONE_KHR
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-
Extending VkEventCreateFlagBits:
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VK_EVENT_CREATE_DEVICE_ONLY_BIT_KHR
-
-
Extending VkImageLayout:
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VK_IMAGE_LAYOUT_ATTACHMENT_OPTIMAL_KHR
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VK_IMAGE_LAYOUT_READ_ONLY_OPTIMAL_KHR
-
-
Extending VkPipelineStageFlagBits:
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VK_PIPELINE_STAGE_NONE_KHR
-
-
Extending VkStructureType:
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VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER_2_KHR
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VK_STRUCTURE_TYPE_COMMAND_BUFFER_SUBMIT_INFO_KHR
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VK_STRUCTURE_TYPE_DEPENDENCY_INFO_KHR
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VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER_2_KHR
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VK_STRUCTURE_TYPE_MEMORY_BARRIER_2_KHR
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VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SYNCHRONIZATION_2_FEATURES_KHR
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VK_STRUCTURE_TYPE_SEMAPHORE_SUBMIT_INFO_KHR
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VK_STRUCTURE_TYPE_SUBMIT_INFO_2_KHR
-
If VK_EXT_blend_operation_advanced is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT
-
If VK_EXT_conditional_rendering is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_CONDITIONAL_RENDERING_READ_BIT_EXT
-
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_CONDITIONAL_RENDERING_BIT_EXT
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If VK_EXT_fragment_density_map is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_FRAGMENT_DENSITY_MAP_READ_BIT_EXT
-
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_FRAGMENT_DENSITY_PROCESS_BIT_EXT
-
If VK_EXT_mesh_shader is supported:
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_MESH_SHADER_BIT_EXT
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VK_PIPELINE_STAGE_2_TASK_SHADER_BIT_EXT
-
If VK_EXT_transform_feedback is supported:
-
Extending VkAccessFlagBits2:
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VK_ACCESS_2_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT
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VK_ACCESS_2_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT
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VK_ACCESS_2_TRANSFORM_FEEDBACK_WRITE_BIT_EXT
-
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_TRANSFORM_FEEDBACK_BIT_EXT
-
If VK_KHR_acceleration_structure is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_ACCELERATION_STRUCTURE_READ_BIT_KHR
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VK_ACCESS_2_ACCELERATION_STRUCTURE_WRITE_BIT_KHR
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Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
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If VK_KHR_fragment_shading_rate is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_FRAGMENT_SHADING_RATE_ATTACHMENT_READ_BIT_KHR
-
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_FRAGMENT_SHADING_RATE_ATTACHMENT_BIT_KHR
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If VK_KHR_ray_tracing_pipeline is supported:
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_RAY_TRACING_SHADER_BIT_KHR
-
If VK_NV_device_diagnostic_checkpoints is supported:
-
Extending VkStructureType:
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VK_STRUCTURE_TYPE_CHECKPOINT_DATA_2_NV
-
VK_STRUCTURE_TYPE_QUEUE_FAMILY_CHECKPOINT_PROPERTIES_2_NV
-
If VK_NV_device_generated_commands is supported:
-
Extending VkAccessFlagBits2:
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VK_ACCESS_2_COMMAND_PREPROCESS_READ_BIT_NV
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VK_ACCESS_2_COMMAND_PREPROCESS_WRITE_BIT_NV
-
-
Extending VkPipelineStageFlagBits2:
-
VK_PIPELINE_STAGE_2_COMMAND_PREPROCESS_BIT_NV
-
If VK_NV_mesh_shader is supported:
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_MESH_SHADER_BIT_NV
-
VK_PIPELINE_STAGE_2_TASK_SHADER_BIT_NV
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If VK_NV_ray_tracing is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_ACCELERATION_STRUCTURE_READ_BIT_NV
-
VK_ACCESS_2_ACCELERATION_STRUCTURE_WRITE_BIT_NV
-
-
Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_ACCELERATION_STRUCTURE_BUILD_BIT_NV
-
VK_PIPELINE_STAGE_2_RAY_TRACING_SHADER_BIT_NV
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If VK_NV_shading_rate_image is supported:
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Extending VkAccessFlagBits2:
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VK_ACCESS_2_SHADING_RATE_IMAGE_READ_BIT_NV
-
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Extending VkPipelineStageFlagBits2:
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VK_PIPELINE_STAGE_2_SHADING_RATE_IMAGE_BIT_NV
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Promotion to Vulkan 1.3
Functionality in this extension is included in core Vulkan 1.3, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.
See Also
VkAccessFlagBits2KHR, VkAccessFlags2KHR, VkBufferMemoryBarrier2KHR, VkCommandBufferSubmitInfoKHR, VkDependencyInfoKHR, VkFlags64, VkImageMemoryBarrier2KHR, VkMemoryBarrier2KHR, VkPhysicalDeviceSynchronization2FeaturesKHR, VkPipelineStageFlagBits2KHR, VkPipelineStageFlags2KHR, VkSemaphoreSubmitInfoKHR, VkSubmitFlagBitsKHR, VkSubmitFlagsKHR, VkSubmitInfo2KHR, vkCmdPipelineBarrier2KHR, vkCmdResetEvent2KHR, vkCmdSetEvent2KHR, vkCmdWaitEvents2KHR, vkCmdWriteTimestamp2KHR, vkQueueSubmit2KHR
Document Notes
For more information, see the Vulkan Specification
This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.