d3d12: Acquire/release keyed mutex around ExecuteCommandLists

D3D keyed mutex cannot be acquired recursively and therefore external
D3D textures cannot be concurrently read within Dawn (e.g. multiple
imports of the same video frame) or across Dawn and GL (e.g. both WebGPU
and WebGL importing a video frame).

Within Dawn, we can scope keyed mutex acquire/release to command list
submission so that Chromium can always guarantee that Dawn doesn't hold
access to any resources after running Dawn wire commands. We also check
that keyed mutexes aren't recursively acquired in Dawn by keeping track
of the acquire count per resource.

This solves the multiple acquire problem within Dawn and provides a path
for concurrent read access across Dawn and GL once the GL decoders are
changed so that they also don't hold access to resources after switching

Bug: chromium:1241533
Change-Id: If88fd4a4f798b972836a134809e4fed8832ec89c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/75644
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Auto-Submit: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
6 files changed
tree: 1e888fa32ab36d9d22238ec6bb55a7b9a51040e3
  1. .vscode/
  2. build_overrides/
  3. docs/
  4. examples/
  5. generator/
  6. infra/
  7. scripts/
  8. src/
  9. third_party/
  10. tools/
  11. .clang-format
  12. .gitattributes
  13. .gitignore
  14. .gn
  16. BUILD.gn
  17. CMakeLists.txt
  18. codereview.settings
  19. dawn.json
  20. dawn_wire.json
  21. DEPS
  24. OWNERS
  25. PRESUBMIT.py
  26. README.chromium
  27. README.md

Dawn's logo: a sun rising behind a stylized mountain inspired by the WebGPU logo. The text Dawn is written below it.

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 the webgpu.h docs)




Apache 2.0 Public License, please see LICENSE.


This is not an officially supported Google product.