Name

VK_EXT_global_priority - device extension

VK_EXT_global_priority

Name String

VK_EXT_global_priority

Extension Type

Device extension

Registered Extension Number

175

Revision

2

Extension and Version Dependencies

• Requires Vulkan 1.0

Contact

• Andres Rodriguez https://github.com/KhronosGroup/Vulkan-Docs/issues/new?title=VK_EXT_global_priority:%20&body=@lostgoat%20

Other Extension Metadata

Last Modified Date

2017-10-06

IP Status

No known IP claims.

Contributors

• Andres Rodriguez, Valve
• Pierre-Loup Griffais, Valve
• Dan Ginsburg, Valve
• Mitch Singer, AMD

Description

In Vulkan, users can specify device-scope queue priorities. In some cases it may be useful to extend this concept to a system-wide scope. This extension provides a mechanism for caller’s to set their system-wide priority. The default queue priority is QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT.

The driver implementation will attempt to skew hardware resource allocation in favour of the higher-priority task. Therefore, higher-priority work may retain similar latency and throughput characteristics even if the system is congested with lower priority work.

The global priority level of a queue shall take precedence over the per-process queue priority (DeviceQueueCreateInfo::pQueuePriorities).

Abuse of this feature may result in starving the rest of the system from hardware resources. Therefore, the driver implementation may deny requests to acquire a priority above the default priority (QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT) if the caller does not have sufficient privileges. In this scenario ERROR_NOT_PERMITTED_EXT is returned.

The driver implementation may fail the queue allocation request if resources required to complete the operation have been exhausted (either by the same process or a different process). In this scenario ERROR_INITIALIZATION_FAILED is returned.

New Structures

• Extending DeviceQueueCreateInfo:

  • DeviceQueueGlobalPriorityCreateInfoEXT

New Enums

• QueueGlobalPriorityEXT

New Enum Constants

• EXT_GLOBAL_PRIORITY_EXTENSION_NAME

• EXT_GLOBAL_PRIORITY_SPEC_VERSION

• Extending Result:

  • ERROR_NOT_PERMITTED_EXT

• Extending StructureType:

  • STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT

Version History

• Revision 2, 2017-11-03 (Andres Rodriguez)

  • Fixed VkQueueGlobalPriorityEXT missing _EXT suffix

• Revision 1, 2017-10-06 (Andres Rodriguez)

  • First version.

See Also

DeviceQueueGlobalPriorityCreateInfoEXT, QueueGlobalPriorityEXT

Document Notes

For more information, see the Vulkan Specification

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