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22a5a1459f
* Update release number to 124.
Github Issues:
* Fix Makefile SPECREMARK macro to work when not building in a git tree
(public issue 992).
* Ignore pname:aspectMask for unused attachments in
slink:VkSubpassDescription2KHR valid usage statements (public pull
request 1028).
* Minor markup / spelling fixes (public pull requests 1035, 1045).
Internal Issues:
* Fix markup in Valid Usage statement for slink:VkCreateFramebuffer
(internal issue 1823).
* Add a new <<synchronization-signal-operation-order, _signal operation
order_>> section to the synchronization chapter which describes in
detail the ordering guarantees provided by the API between fence and
semaphore signal operations (internal merge request 3368).
* Move generated `appendix/meta/` files into the Makefile GENERATED
directory (internal merge request 3381).
New Extensions
* `<<VK_KHR_shader_clock>>`
* `<<VK_KHR_timeline_semaphore>>`
101 lines
3.9 KiB
Plaintext
101 lines
3.9 KiB
Plaintext
// Copyright (c) 2017-2019 Khronos Group. This work is licensed under a
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// Creative Commons Attribution 4.0 International License; see
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// http://creativecommons.org/licenses/by/4.0/
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include::{generated}/meta/VK_EXT_subgroup_size_control.txt[]
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*Last Modified Date*::
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2019-03-05
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*Contributors*::
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- Jeff Bolz, NVIDIA
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- Jason Ekstrand, Intel
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- Sławek Grajewski, Intel
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- Jesse Hall, Google
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- Neil Henning, AMD
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- Daniel Koch, NVIDIA
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- Jeff Leger, Qualcomm
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- Graeme Leese, Broadcom
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- Allan MacKinnon, Google
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- Mariusz Merecki, Intel
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- Graham Wihlidal, Electronic Arts
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=== Short Description
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Enables an implementation to control the subgroup size by allowing a varying
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subgroup size and also specifying a required subgroup size.
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=== Description
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This extension extends the subgroup support in Vulkan 1.1 to allow an
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implementation to expose a varying subgroup size.
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Previously Vulkan exposed a single subgroup size per physical device, with
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the expectation that implementations will behave as if all subgroups have
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the same size.
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Some implementations may: dispatch shaders with a varying subgroup size for
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different subgroups.
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As a result they could implicitly split a large subgroup into smaller
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subgroups or represent a small subgroup as a larger subgroup, some of whose
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invocations were inactive on launch.
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To aid developers in understanding the performance characteristics of their
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programs, this extension exposes a minimum and maximum subgroup size that a
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physical device supports and a pipeline create flag to enable that pipeline
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to vary its subgroup size.
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If enabled, any code:SubgroupSize decorated variables in the SPIR-V shader
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modules provided to pipeline creation may: vary between the
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<<limits-min-subgroup-size,minimum>> and
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<<limits-max-subgroup-size,maximum>> subgroup sizes.
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An implementation is also optionally allowed to support specifying a
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required subgroup size for a given pipeline stage.
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Implementations advertise which <<limits-required-subgroup-size-stages,
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stages support a required subgroup size>>, and any pipeline of a supported
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stage can be passed a
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slink:VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure to
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set the subgroup size for that shader stage of the pipeline.
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For compute shaders, this requires the developer to query the
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<<limits-max-subgroups-per-workgroup, pname:maxComputeWorkgroupSubgroups>>
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and ensure that:
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[latexmath]
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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s = {WorkGroupSize.x * WorkGroupSize.y * WorkgroupSize.z <= SubgroupSize * maxComputeWorkgroupSubgroups }
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++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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Developers can also specify a new pipeline shader stage create flag that
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requires the implementation to have fully populated subgroups within local
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workgroups.
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This requires the workgroup size in the X dimension to be a multiple of the
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subgroup size.
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=== New Enum Constants
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* Extending elink:VkStructureType:
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_FEATURES_EXT
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(added in version 2)
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** ename:VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_PROPERTIES_EXT
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** ename:VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_REQUIRED_SUBGROUP_SIZE_CREATE_INFO_EXT
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* Extending elink:VkPipelineShaderStageCreateFlagBits:
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** ename:VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT
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** ename:VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT
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=== New Structures
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* slink:VkPhysicalDeviceSubgroupSizeControlFeaturesEXT (added in version
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2)
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* slink:VkPhysicalDeviceSubgroupSizeControlPropertiesEXT
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* slink:VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT
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=== Issues
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None.
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=== Version History
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* Revision 1, 2019-03-05 (Neil Henning)
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- Initial draft
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* Revision 2, 2019-07-26 (Jason Ekstrand)
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- Add the missing slink:VkPhysicalDeviceSubgroupSizeControlFeaturesEXT
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for querying subgroup size control features.
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