73 lines
2.0 KiB
Plaintext
73 lines
2.0 KiB
Plaintext
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include::meta/VK_EXT_global_priority.txt[]
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*Last Modified Date*::
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2017-10-06
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*IP Status*::
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No known IP claims.
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*Contributors*::
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- Andres Rodriguez, Valve
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- Pierre-Loup Griffais, Valve
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- Dan Ginsburg, Valve
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- Mitch Singer, AMD
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In Vulkan, users can specify device-scope queue priorities.
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In some cases it may be useful to extend this concept to a system-wide
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scope.
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This extension provides a mechanism for caller's to set their system-wide
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priority.
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The default queue priority is elink:VK_QUEUE_GLOBAL_PRIORITY_MEDIUM.
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The driver implementation will attempt to skew hardware resource allocation
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in favour of the higher-priority task.
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Therefore, higher-priority work may retain similar latency and throughput
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characteristics even if the system is congested with lower priority work.
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The global priority level of a queue shall take predence over the
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per-process queue priority
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(sname:VkDeviceQueueCreateInfo::pname:pQueuePriorities).
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Abuse of this feature may result in starving the rest of the system from
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hardware resources.
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Therefore, the driver implementation may deny requests to acquire a priority
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above the default priority (elink:VK_QUEUE_GLOBAL_PRIORITY_MEDIUM) if the
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caller does not have sufficient privileges.
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In this scenario elink:VK_ERROR_NOT_PERMITTED_EXT is returned.
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The driver implementation may fail the queue allocation request if resources
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required to complete the operation have been exhausted (either by the same
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process or a different process).
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In this scenario elink:VK_ERROR_INITIALIZATION_FAILED is returned.
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=== New Object Types
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None.
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=== New Enum Constants
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* Extending elink:VkStructureType:
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** elink:VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT
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* Extending elink:VkResult:
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** elink:VK_ERROR_NOT_PERMITTED_EXT
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=== New Enums
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* elink:VkQueueGlobalPriorityEXT
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=== New Structures
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* slink:VkDeviceQueueGlobalPriorityCreateInfoEXT
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=== New Functions
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None.
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=== Issues
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None.
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=== Version History
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* Revision 1, 2017-10-06 (Andres Rodriguez)
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- First version.
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