tree e1903714867712eddff2628b29e2530d38d1f2c7
parent 5cef1162b9af6c9377cc8f41c019b5cdc456c77f
author Corentin Wallez <cwallez@chromium.org> 1592299068 +0000
committer Commit Bot service account <commit-bot@chromium.org> 1592299068 +0000

Reland: Vulkan: Enforce fixed subgroup size for compute shaders.

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>.

This CL ensures that, on architectures with a varying subgroup size,
compute shaders are always compiled with a fixed subgroup size to
avoid consistency issues when one shader writes data in a subgroup-size
dependent layout to GPU memory, to be read by another shader in a
future dispatch.

At the moment, only Intel ICDs are known to implement this [1],
and the code uses a heuristics to chose the size of 16, which seems to
be the sweet spot according to Intel engineers.

+ Update the PNextChainBuilder class to deal with the fact that
  VkComputePipelineCreateInfo::pNext is defined as a const void*,
  which created compiler errors in the previous implementation.

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

Bug: dawn:464
Change-Id: I035ee06084fcc964742f0bff4c54cff257c742ae
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/23202
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>