VK_EXT_global_priority

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

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 callers to set their system-wide priority. The default queue priority is VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT.

The driver implementation will attempt to skew hardware resource allocation in favor 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 (VkDeviceQueueCreateInfo::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 (VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT) if the caller does not have sufficient privileges. In this scenario VK_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 VK_ERROR_INITIALIZATION_FAILED is returned.

New Structures

Extending VkDeviceQueueCreateInfo:
- VkDeviceQueueGlobalPriorityCreateInfoEXT

New Enums

VkQueueGlobalPriorityEXT

New Enum Constants

VK_EXT_GLOBAL_PRIORITY_EXTENSION_NAME
VK_EXT_GLOBAL_PRIORITY_SPEC_VERSION
Extending VkResult:
- VK_ERROR_NOT_PERMITTED_EXT
Extending VkStructureType:
- VK_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.