commit e3f3e9a80d5f937470aacda7b810a88fc85e8b19
author Corentin Wallez <cwallez@chromium.org> Fri Mar 06 13:27:10 2020 +0000
committer Commit Bot service account <commit-bot@chromium.org> Fri Mar 06 13:27:10 2020 +0000
tree c4e51f8d83d97bb37b9aec6ea97acdc3a0dde825
parent 36f0388f794b181c3adb8d993eccce1062c81642

Revert "Vulkan: Report and enable subgroup size control device extension."

This reverts commit 4ae315b0d11882f341c22147672e1661bcb3b7d7.

Reason for revert: crbug.com/1059205

Bug: chromium:1059205

Original change's description:
> Vulkan: Report and enable subgroup size control device extension.
> 
> 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:
> 
> - The corresponding VkStructureType enum values and
>   struct types are not rolled to the third-party Vulkan
>   headers used by Dawn yet, so vulkan_platform.h has been
>   modified to define them if necessary. This can be
>   removed in the future when the Vulkan-Headers are
>   updated in a different patch.
> 
> - This modifies VulkanDeviceInfo::GatherDeviceInfo() to
>   use VkGetPhysicalDevice{Properties2,Features2} if the
>   VK_KHR_get_device_properties2 instance extension is
>   available. Otherwise, the Vulkan 1.0 APIs
>   VkGetPhysicalDevice{Properties,Features} are used instead
>   (and it is assumed that no subgroup size control is
>   possible).
> 
> - 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.
> 
> 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
> 
> Change-Id: I524af6ff3479f25b0a8bb139a062fe632c826893
> Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/16020
> Reviewed-by: Austin Eng <enga@chromium.org>
> Reviewed-by: Corentin Wallez <cwallez@chromium.org>
> Commit-Queue: Corentin Wallez <cwallez@chromium.org>

TBR=cwallez@google.com,cwallez@chromium.org,enga@chromium.org,enga@google.com,david.turner.dev@gmail.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I893d771d7effdf83685dda3edac8a08f98d2f6e5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/16522
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>