[ExecuTorch][WebGPU] Add softmax ops (_softmax, _log_softmax) to the WebGPU backend by JCNTH · Pull Request #20919 · pytorch/executorch

JCNTH · 2026-07-14T21:48:13Z

Stack from ghstack (oldest at bottom):

Add aten._softmax + aten._log_softmax handlers (max-stable online softmax) for the training tail.

Key changes:

runtime/ops/{softmax,log_softmax}/ — max-stable softmax + log_softmax WGSL kernels + handlers
CMakeLists.txt WEBGPU_SRCS — wire the sources

Reuses the shared Vulkan partitioner (aten._softmax/_log_softmax already registered); WebGPU kernels only.

Co-authored-with: Claude Code.
@exported-using-ghexport

Differential Revision: D111755118

[ghstack-poisoned]

pytorch-bot · 2026-07-14T21:48:16Z

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/20919

📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 53 New Failures, 6 Unclassified Failures

As of commit 387daf1 with merge base 21554e5 ():

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pull / nxp-build-test / linux-job (gh)
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pull / test-arm-backend-no-driver (test_pytest_models_tosa) / linux-job (gh)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
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pull / test-arm-cortex-m-size-test (bare_metal) / linux-job (gh)
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pull / test-models-linux (add_mul, xnnpack-quantization-delegation, linux.2xlarge) / linux-job (gh)
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pull / test-models-linux (add, portable, linux.2xlarge) / linux-job (gh)
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pull / test-models-linux (emformer_transcribe, xnnpack-quantization-delegation, linux.2xlarge) / linux-job (gh)
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pull / test-models-linux (ic3, portable, linux.2xlarge) / linux-job (gh)
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pull / test-models-linux (mv2, portable, linux.2xlarge) / linux-job (gh)
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pull / test-models-linux (mv2, xnnpack-quantization-delegation, linux.2xlarge) / linux-job (gh)
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pull / test-qnn-models-linux (dl3) / linux-job (gh)
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pull / test-qnn-models-linux (mv2) / linux-job (gh)
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UNCLASSIFIED FAILURES - DrCI could not classify the following jobs because the workflow did not run on the merge base. The failures may be pre-existing on trunk or introduced by this PR:

periodic / test-models-linux (buck2, mv3, portable, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
periodic / test-models-linux (buck2, mv3, xnnpack-quantization-delegation, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
periodic / test-models-linux (cmake, mv3, portable, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
periodic / test-models-linux (cmake, mv3, xnnpack-quantization-delegation, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
periodic / test-models-linux (cmake, vit, portable, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory
periodic / test-models-linux (cmake, vit, xnnpack-quantization-delegation, linux.2xlarge, 90) / linux-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
An error occurred trying to start process '/usr/bin/bash' with working directory '/home/ec2-user/actions-runner/_work/executorch/executorch/pytorch/executorch'. No such file or directory

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github-actions · 2026-07-14T21:49:47Z

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…WebGPU backend Pull Request resolved: #20919 Add `aten._softmax` + `aten._log_softmax` handlers (max-stable online softmax) for the training tail. Key changes: - `runtime/ops/{softmax,log_softmax}/` — max-stable softmax + log_softmax WGSL kernels + handlers - `CMakeLists.txt` `WEBGPU_SRCS` — wire the sources Reuses the shared Vulkan partitioner (`aten._softmax`/`_log_softmax` already registered); WebGPU kernels only. Co-authored-with: Claude Code. ghstack-source-id: 405026047 @exported-using-ghexport Differential Revision: [D111755118](https://our.internmc.facebook.com/intern/diff/D111755118/)

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[ExecuTorch][WebGPU] Glob runtime/ops sources in CMakeLists #21005

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meta-codesync Bot merged commit 8da7912 into gh/JCNTH/58/base Jul 21, 2026
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[ExecuTorch][WebGPU] Add softmax ops (_softmax, _log_softmax) to the WebGPU backend #21072

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[ExecuTorch][WebGPU] Add softmax ops (_softmax, _log_softmax) to the WebGPU backend#20919

[ExecuTorch][WebGPU] Add softmax ops (_softmax, _log_softmax) to the WebGPU backend#20919
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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/20919

❌ 53 New Failures, 6 Unclassified Failures

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