Subgroups feature not supported (but 'subgroup' is)

[HongchengZhao]

Describe the bug

When I try to request device with subgroups feature, it throws an error KeyError: "Unknown feature: 'subgroups'"

To Reproduce

adapter = wgpu.gpu.request_adapter_sync(power_preference=wgpu.PowerPreference.high_performance)
device = adapter.request_device_sync(required_features=[wgpu.FeatureName.subgroups])

Your environment

OS: Linux
python: 3.10
wgpu-py: 0.22.2

[almarklein]

subgroups are not yet supported by wgpu-native. I'm not 100% sure, but it could be that we'd have them after #718

[HongchengZhao]

subgroups are not yet supported by wgpu-native. I'm not 100% sure, but it could be that we'd have them after #718

By searching subgroup in the wgpu-native repository, I acturally find this. It seems that subgroups feature is already supported, but somehow it's named as subgroup, against the WebGPU spec.

And after I changed the code to the following, it suprisingly runs without throwing an error! And my compute shader using subgroups also worked as expected.

device = adapter.request_device_sync(required_features=["subgroup"])

[almarklein]

That's odd, we have this line in our code:

wgpu-py/wgpu/backends/wgpu_native/_api.py

Line 405 in d25edb1

not_supported_by_wgpu_native = {"subgroups"}

Can you confirm that your compute shader does not work when you omit the required features?

Maybe we just need to map the name 🤷

[HongchengZhao]

That's odd, we have this line in our code:

wgpu-py/wgpu/backends/wgpu_native/_api.py

Line 405 in d25edb1

not_supported_by_wgpu_native = {"subgroups"}
Can you confirm that your compute shader does not work when you omit the required features?

Maybe we just need to map the name 🤷

Yes, I can confirm that without requesting the subgroup feature, the code throws the following error.

Shader validation error: Entry point test_subgroup at Compute is invalid
 = Argument 4 varying error
 = Capability Capabilities(SUBGROUP) is not supported


      Entry point test_subgroup at Compute is invalid
        Argument 4 varying error
          Capability Capabilities(SUBGROUP) is not supported

But I am simply using subgroup_size, have not tested other subgroup features.

Edit:

I guess it's supported by this PR gfx-rs/wgpu-native#438

[almarklein]

Ok, I'll reopen this, I think we simply need to map this feature name.

[Vipitis]

hm, curious one. What I think might be the case, it was a native only feature called subgroup but now there is an official feature called subgroups.

I will ask this upstream: gfx-rs/wgpu#5555