VK_EXT_pipeline_properties

Other Extension Metadata

Last Modified Date

2022-04-19

IP Status

No known IP claims.

Contributors

• Mukund Keshava, NVIDIA
• Daniel Koch, NVIDIA
• Mark Bellamy, Arm

Description

Vulkan SC requires offline compilation of pipelines. In order to support this, the pipeline state is represented in a JSON schema that is read by an offline tool for compilation.

One method of developing a Vulkan SC application is to author a Vulkan application and use a layer to record and serialize the pipeline state and shaders for offline compilation. Each pipeline is represented by a separate JSON file, and can be identified with a pipelineIdentifier.

Once the pipelines have been compiled by the offline pipeline cache compiler, the Vulkan SC application can then use this pipelineIdentifier for identifying the pipeline via Vulkan SC’s VkPipelineIdentifierInfo structure.

This extension allows the Vulkan application to query the pipelineIdentifier associated with each pipeline so that the application can store this with its pipeline metadata and the Vulkan SC application will then use to map the same state to an entry in the Vulkan SC pipeline cache.

It is expected that this extension will initially be implemented in the json generation layer, although we can envision that there might be future uses for it in native Vulkan drivers as well.

New Commands

• vkGetPipelinePropertiesEXT

New Structures

• VkPipelineInfoEXT
• VkPipelinePropertiesIdentifierEXT
• Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
  • VkPhysicalDevicePipelinePropertiesFeaturesEXT

New Enum Constants

• VK_EXT_PIPELINE_PROPERTIES_EXTENSION_NAME
• VK_EXT_PIPELINE_PROPERTIES_SPEC_VERSION
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_PROPERTIES_FEATURES_EXT
  • VK_STRUCTURE_TYPE_PIPELINE_INFO_EXT
  • VK_STRUCTURE_TYPE_PIPELINE_PROPERTIES_IDENTIFIER_EXT

Issues

(1) This extension does not make sense on a strict Vulkan SC implementation. It may however be of potential use in a non-strict Vulkan SC implementation. Should this extension be enabled as part of Vulkan SC as well?

RESOLVED: No. This extension will not be enabled for Vulkan SC.

(2) This is intended to be a general pipeline properties query, but is currently only retrieving the pipeline identifier. Should the pipeline identifier query be mandatory for this extension and for all queries using this command?

RESOLVED: Use VkBaseOutStructure for the return parameter. Currently this is required to actually be a VkPipelinePropertiesIdentifierEXT structure, but that could be relaxed in the future to allow other structure types or to allow other structures to be chained in along with this one.

(3) Should there be a feature structure? Should it be required?

RESOLVED: Add a feature structure, and a feature for querying pipeline identifier, but allow it to be optional so that this extension can be used as the basis for other pipeline property queries without requiring the pipeline identifier to be supported.

Version History

• Revision 1, 2022-04-19 (Mukund Keshava, Daniel Koch)
  • Initial draft