Name

VK_EXT_global_priority_query - device extension

VK_EXT_global_priority_query

Name String

VK_EXT_global_priority_query

Extension Type

Device extension

Registered Extension Number

389

Revision

1

Ratification Status

Not ratified

Extension and Version Dependencies

VK_EXT_global_priority and VK_KHR_get_physical_device_properties2

Deprecation State

• Promoted to VK_KHR_global_priority extension

Contact

• Yiwei Zhang @zhangyiwei%0A*Here describe the issue or question you have about the VK_EXT_global_priority_query extension*

Other Extension Metadata

Last Modified Date

2021-03-29

IP Status

No known IP claims.

Contributors

• Yiwei Zhang, Google

Description

This device extension allows applications to query the global queue priorities supported by a queue family. It allows implementations to report which global priority levels are treated differently by the implementation, instead of silently mapping multiple requested global priority levels to the same internal priority, or using device creation failure to signal that a requested priority is not supported. It is intended primarily for use by system integration along with certain platform-specific priority enforcement rules.

New Structures

• Extending PhysicalDeviceFeatures2, DeviceCreateInfo:

  • PhysicalDeviceGlobalPriorityQueryFeaturesEXT

• Extending QueueFamilyProperties2:

  • QueueFamilyGlobalPriorityPropertiesEXT

New Enum Constants

• EXT_GLOBAL_PRIORITY_QUERY_EXTENSION_NAME

• EXT_GLOBAL_PRIORITY_QUERY_SPEC_VERSION
• MAX_GLOBAL_PRIORITY_SIZE_EXT

• Extending StructureType:

  • STRUCTURE_TYPE_PHYSICAL_DEVICE_GLOBAL_PRIORITY_QUERY_FEATURES_EXT
  • STRUCTURE_TYPE_QUEUE_FAMILY_GLOBAL_PRIORITY_PROPERTIES_EXT

Issues

1) Can we additionally query whether a caller is permitted to acquire a specific global queue priority in this extension?

RESOLVED: No. Whether a caller has enough privilege goes with the OS, and the Vulkan driver cannot really guarantee that the privilege will not change in between this query and the actual queue creation call.

2) If more than 1 queue using global priority is requested, is there a good way to know which queue is failing the device creation?

RESOLVED: No. There is not a good way at this moment, and it is also not quite actionable for the applications to know that because the information may not be accurate. Queue creation can fail because of runtime constraints like insufficient privilege or lack of resource, and the failure is not necessarily tied to that particular queue configuration requested.

Version History

• Revision 1, 2021-03-29 (Yiwei Zhang)

See Also

MAX_GLOBAL_PRIORITY_SIZE_EXT, PhysicalDeviceGlobalPriorityQueryFeaturesEXT, QueueFamilyGlobalPriorityPropertiesEXT

Document Notes

For more information, see the Vulkan Specification

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