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Corentin Wallez 5cef1162b9 Reland: Vulkan: Report and enable subgroup size control device extension.
Reland after a refactor of how the extension handling work in the Vulkan
backend.

The original author is David Turner <david.turner.dev@gmail.com>.

Certain Vulkan ICDs (Intel ones notably) will compile SPIR-V
shaders with an liberal, compiler-selected, subgroup size (i.e.
either 8, 16 or 32). For more context, see [1].

This can be a problem for compute, when one shader stores data
in device memory using a subgroup-size dependent layout, to be
consumed by a another shader. Problems arise when the compiler
decides to compile both shaders with different subgroup sizes.

To work-around this, the VK_EXT_subgroup_size_control device
extension was introduced recently: it allows the device to
report the min/max subgroup sizes it provides, and allows
the Vulkan program to control the subgroup size precisely
if it wants to.

This patch adds support to the Vulkan backend to report and
enable the extension if it is available. Note that:

- This changes the definition of VulkanDeviceKnobs to
  make room for the required pNext-linked chains of
  extensions.

- A helper class, PNextChainBuilder is also provided in
  UtilsVulkan.h to make it easy to build pNext-linked
  extension struct chains at runtime, as required when
  probing device propertires/features, or when
  creating a new VkDevice handle.

- This modifies VulkanDeviceInfo::GatherDeviceInfo() to
  use PNextChainBuilder to query extension features and properties
  in a single call to vkGetPhysicalDevice{Properties,Features}2.

Apart from that, there is no change in behaviour in this CL.
I.e. a later CL might force a specific subgroup size for
consistency, or introduce a new API to let Dawn clients
select a fixed subgroup size.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=108875

Bug: dawn:464
Change-Id: I01e5c28e7dac66f0a57bf35532eb192912b254fa
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/23201
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
2020-06-16 07:54:28 +00:00
build_overrides Add Tint to BUILD.gn 2020-05-07 21:15:55 +00:00
docs Deprecate Buffer::SetSubData in favor of Queue::WriteBuffer 2020-06-02 09:24:39 +00:00
examples Deprecate TextureCopyView::arrayLayer -> origin.z 2020-06-16 03:05:17 +00:00
generator Remove deprecated "Binding" types and members 2020-05-13 17:05:55 +00:00
infra/config infra: Migrate builders to Goma RBE 2020-06-09 12:34:02 +00:00
scripts Set a default value for dawn_glm_dir like other GN build overrides 2020-05-27 01:33:33 +00:00
src Reland: Vulkan: Report and enable subgroup size control device extension. 2020-06-16 07:54:28 +00:00
third_party Fix and enable -Wgnu-anonymous-struct 2020-04-30 16:01:08 +00:00
tools/memory/asan Fix is_asan build (at least on Mac) 2020-04-06 22:27:02 +00:00
.clang-format Add .clang-format 2017-11-28 16:18:39 -05:00
.gitattributes Add .gitattributes to normalize EOL 2019-07-15 12:23:18 +00:00
.gitignore Add Tint to BUILD.gn 2020-05-07 21:15:55 +00:00
.gn Re-enable -Wunguarded-availability in Dawn standalone builds 2019-12-11 16:54:51 +00:00
AUTHORS Rename NXT -> Dawn in the comments 2018-07-18 22:54:06 +02:00
BUILD.gn Remove temporary GN proxy groups. 2020-04-14 17:36:44 +00:00
CMakeLists.txt Fix the CMake build because of CMP0077 2020-04-10 17:04:31 +00:00
CONTRIBUTING.md docs: write an overview of Dawn and split README.md 2019-12-05 11:01:41 +00:00
DEPS Rolling 3 dependencies 2020-06-15 19:00:52 +00:00
LICENSE Initial commit of all the NXT integration. 2017-04-20 14:38:20 -04:00
OWNERS Add enga@chromium.org as OWNER 2020-04-02 18:14:37 +00:00
PRESUBMIT.py PRESUBMIT.py: Add formatting checks. 2018-09-11 08:06:36 -04:00
README.chromium Add component to OWNERS and fixup repo URL in README.chromium 2018-09-25 20:53:37 +00:00
README.md Add Matrix chatrooms to README.md 2020-04-24 12:38:13 +00:00
codereview.settings Initial CQ configuration 2018-08-23 08:33:35 -04:00
dawn.json Handle OOM buffer allocations better 2020-06-15 23:42:13 +00:00
dawn_wire.json Deprecate Buffer::SetSubData in favor of Queue::WriteBuffer 2020-06-02 09:24:39 +00:00

README.md

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the work-in-progress WebGPU standard. More precisely it implements webgpu.h that is a one-to-one mapping with the WebGPU IDL. Dawn is meant to be integrated as part of a larger system and is the underlying implementation of WebGPU in Chromium.

Dawn provides several WebGPU building blocks:

  • WebGPU C/C++ headers that applications and other building blocks use.
    • The webgpu.h version that Dawn implements.
    • A C++ wrapper for the webgpu.h.
  • A "native" implementation of WebGPU using platforms' GPU APIs:
    • D3D12 on Windows 10
    • Metal on macOS and iOS
    • Vulkan on Windows, Linux, ChromeOS, Android and Fuchsia
    • OpenGL as best effort where available
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers

Helpful links:

Documentation table of content

Developer documentation:

User documentation: (TODO, figure out what overlaps with webgpu.h docs)

Status

(TODO)

License

Apache 2.0 Public License, please see LICENSE.

Disclaimer

This is not an officially supported Google product.