[native] Deduplicate BindGroup usage tracking per pass

In a render pass, render bundle or compute pass, rebinding the same
BindGroup across draws or dispatches (e.g. with varying dynamic offsets)
repeatedly walks the bind group layout and records identical
whole-resource usage on every SetBindGroup call.

Add a 64-bit PassTrackerID TypedInteger generated atomically by
DeviceBase (GetNextPassTrackerID) and give one to each pass-level
tracker (RenderPassResourceUsageTracker and
ComputePassResourceUsageTracker). Track the last pass tracker a
BindGroup was recorded in intrusively on BindGroupBase via an
atomic<PassTrackerID> checked in ShouldAddToPassTracker() with relaxed
atomics. Duplicate additions caused by concurrent use in multiple
encoders are benign.

- Render passes and bundles:
  RenderPassResourceUsageTracker::AddBindGroup skips bind groups
  already recorded in the pass.
- Compute passes:
  ComputePassResourceUsageTracker::AddResourcesReferencedByBindGroup
  skips bind groups already referenced in the pass. Per-dispatch
  synchronization scopes still record every bind group since each
  dispatch needs its own SyncScopeResourceUsage.

To keep a single, type-safe code path, the non-deduplicated walk
becomes the protected SyncScopeUsageTracker::AddBindGroupUsages(), and
a new DispatchResourceUsageTracker exposes it as AddBindGroup() for the
per-dispatch scopes of compute passes.

On Animometer (10,000 draws/frame), this reduces AddBindGroup CPU cycle
cost from 7.00% to 0.71% (~220 us saved per frame) on Adreno 840.
Gained 8.8% CPU FPS. With 1,000 to 10,000 dispatches per frame that
rebind the same bind group with dynamic offsets, this reduces Dawn CPU
instructions per frame by 4-6% on Pixel 11.

Bug: b/564314926, b/570398140
Change-Id: I682bacceafa6d1de156e0b61669d8f814303d17a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/342775
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Sanjeevi Suresh <sanjeevisuresh@google.com>
14 files changed
tree: c56c31672f9894b2e352f6e4aeca7887d96ec096
  1. .github/
  2. .vscode/
  3. agents/
  4. build_overrides/
  5. docs/
  6. generator/
  7. include/
  8. infra/
  9. scripts/
  10. src/
  11. test/
  12. third_party/
  13. tools/
  14. webgpu-cts/
  15. .bazelignore
  16. .bazelrc
  17. .bazelversion
  18. .clang-format
  19. .clang-format-ignore
  20. .clang-tidy
  21. .git-blame-ignore-revs
  22. .gitattributes
  23. .gitignore
  24. .gitmodules
  25. .gn
  26. .style.yapf
  27. AUTHORS
  28. BUILD.bazel
  29. BUILD.gn
  30. CMakeLists.txt
  31. CMakeSettings.json
  32. CODE_OF_CONDUCT.md
  33. codereview.settings
  34. CONTRIBUTING.md
  35. CPPLINT.cfg
  36. DEPS
  37. DIR_METADATA
  38. go.mod
  39. go.sum
  40. go_presubmit_support.py
  41. LICENSE
  42. MODULE.bazel
  43. OWNERS
  44. PRESUBMIT.py
  45. PRESUBMIT_test.py
  46. README.chromium
  47. README.md
  48. unsafe_buffers_paths.txt
  49. vpython.toml
  50. vpython.toml.uv.lock
  51. WATCHLISTS
  52. WORKSPACE.bazel
README.md

Build Status Matrix Space

Dawn, a WebGPU implementation

Dawn is an open-source and cross-platform implementation of the 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, Metal, Vulkan and OpenGL. See per API support for more details.
  • A client-server implementation of WebGPU for applications that are in a sandbox without access to native drivers
  • Tint is a compiler for the WebGPU Shader Language (WGSL) that can be used in standalone to convert shaders from and to WGSL.

Helpful links:

Documentation table of content

Developer documentation:

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

License

BSD 3-Clause License, please see LICENSE.

Disclaimer

This is not an officially supported Google product.