[cutlass-4][take 2] upgrade to cutlass 4.2.1 by henrylhtsang · Pull Request #164159 · pytorch/pytorch

henrylhtsang · 2025-09-29T17:57:45Z

Test Plan: Sandcastle

Differential Revision: D83492704

cc @voznesenskym @penguinwu @EikanWang @jgong5 @Guobing-Chen @XiaobingSuper @zhuhaozhe @blzheng @wenzhe-nrv @jiayisunx @ipiszy @chenyang78 @kadeng @muchulee8 @amjames @chauhang @aakhundov @coconutruben

pytorch-bot · 2025-09-29T17:57:49Z

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🧪 See artifacts and rendered test results at hud.pytorch.org/pr/164159

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❌ 2 New Failures

As of commit aa16e5e with merge base 566ea4e ():

NEW FAILURES - The following jobs have failed:

inductor / unit-test / inductor-cpu-build / build (gh)
Failed to resolve action download info.
inductor / unit-test / inductor-halide-build / build (gh)
The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.

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facebook-github-bot · 2025-09-29T17:58:09Z

@henrylhtsang has exported this pull request. If you are a Meta employee, you can view the originating diff in D83492704.

Skylion007 · 2025-09-29T18:34:13Z

torch/_inductor/codegen/cuda/cutlass_utils.py

@@ -421,7 +421,7 @@ def get_max_alignment(inductor_layout: Layout) -> int:
    offset = inductor_layout.offset

    def is_static_int(number):


Suggested change

def is_static_int(number):

def is_static_int(number: object) -> Type[int | sympy.Integer]:

Otherwise this will hide the type information of the isinstance call...

Skylion007 · 2025-09-29T18:34:46Z

torch/_inductor/codegen/cuda/cutlass_lib_extensions/evt_extensions.py

@@ -234,7 +234,6 @@ def _get_arg_from_node(
        # node's memory, a stride tuple, the datatype
        # Once again, need to check for local class type for stride tuple
        if str(arg_ty) in {


This should be an equality check now

Skylion007 · 2025-09-29T18:34:57Z

torch/_inductor/codegen/cuda/cutlass_lib_extensions/evt_extensions.py

@@ -173,7 +174,6 @@ def _render_argument_type(
        # Fragile, but this is the only way to guarantee t is expected type because t is a local class
        def is_nested_visitor_type(t: type) -> bool:
            return ".".join([t.__module__, t.__qualname__]) in {


same here...

Skylion007 · 2025-09-29T18:35:32Z

torch/_inductor/codegen/cuda/cutlass_lib_extensions/evt_extensions.py

+        import cutlass_cppgen as python_cutlass  # type: ignore[import-untyped, import-not-found]  # noqa: F401
    else:
        import cutlass_cppgen as python_cutlass  # type: ignore[import-untyped, import-not-found]  # noqa: F401


Suggested change

import cutlass_cppgen as python_cutlass # type: ignore[import-untyped, import-not-found] # noqa: F401

else:

import cutlass_cppgen as python_cutlass # type: ignore[import-untyped, import-not-found] # noqa: F401

import cutlass_cppgen as python_cutlass # type: ignore[import-untyped, import-not-found] # noqa: F401

henrylhtsang · 2025-09-29T18:35:53Z

@Skylion007 unfortunately vllm side is very tricky. vllm-project/vllm#24673

Skylion007 · 2025-09-29T18:40:20Z

@Skylion007 unfortunately vllm side is very tricky. vllm-project/vllm#24673

Hmm, the other PR is currently merging though and missing some of these other import changes? So CUTLASS inductor will be broken after the other PR lands? Or are you saying VLLM will need to use an old version of CUTLASS temporarily.

henrylhtsang · 2025-09-29T18:42:45Z

@Skylion007 unfortunately vllm side is very tricky. vllm-project/vllm#24673

Hmm, the other PR is currently merging though and missing some of these other import changes? So CUTLASS inductor will be broken after the other PR lands? Or are you saying VLLM will need to use an old version of CUTLASS temporarily.

I think there are two upgrade going on:

one for pytorch OSS: [submodule] upgrade cutlass version to 4.2.1 and completely resolved python/cutlass name collision #164156 okay to merge
one for fbcode, which pytorch and vllm also depend, which is this one. This one is not landing anytime soon...

Summary: Pull Request resolved: pytorch#164159 Test Plan: Sandcastle Differential Revision: D83492704

facebook-github-bot · 2025-10-01T23:38:29Z

@henrylhtsang has exported this pull request. If you are a Meta employee, you can view the originating Diff in D83492704.

facebook-github-bot · 2025-10-03T03:36:05Z

@pytorchbot merge

(Initiating merge automatically since Phabricator Diff has merged)

pytorchmergebot · 2025-10-03T03:37:59Z

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pytorchmergebot · 2025-10-03T03:38:14Z

Merge failed

Reason: 2 jobs have failed, first few of them are: inductor / unit-test / inductor-halide-build / build, inductor / unit-test / inductor-cpu-build / build

Details for Dev Infra team

Raised by workflow job

henrylhtsang · 2025-10-03T03:40:33Z

@pytorchbot merge -i

pytorchmergebot · 2025-10-03T03:42:22Z

Merge started

Your change will be merged while ignoring the following 2 checks: inductor / unit-test / inductor-halide-build / build, inductor / unit-test / inductor-cpu-build / build

Learn more about merging in the wiki.

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…4589) Differential Revision: D83809105 Handle reviews from #164159 Pull Request resolved: #164589 Approved by: https://github.com/Skylion007

Test Plan: Sandcastle Differential Revision: D83492704 Pull Request resolved: pytorch#164159 Approved by: https://github.com/Skylion007, https://github.com/mlazos

…orch#164589) Differential Revision: D83809105 Handle reviews from pytorch#164159 Pull Request resolved: pytorch#164589 Approved by: https://github.com/Skylion007

pytorch-bot bot added ciflow/inductor module: inductor labels Sep 29, 2025

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Skylion007 added topic: not user facing topic category release notes: cuda release notes category and removed topic: not user facing topic category labels Sep 29, 2025

[cutlass-4][take 2] upgrade to cutlass 4.2.1 (pytorch#164159)

aa16e5e

Summary: Pull Request resolved: pytorch#164159 Test Plan: Sandcastle Differential Revision: D83492704

henrylhtsang force-pushed the export-D83492704 branch from e6be173 to aa16e5e Compare October 1, 2025 23:38

pytorchmergebot added the merging label Oct 3, 2025

pytorchmergebot removed the merging label Oct 3, 2025

pytorchmergebot added the merging label Oct 3, 2025

pytorchmergebot closed this in 6c209bf Oct 3, 2025

pytorchmergebot added the Merged label Oct 3, 2025

pytorchmergebot removed the merging label Oct 3, 2025

henrylhtsang mentioned this pull request Oct 3, 2025

[BE][cutlass backend] BE changes post cutlass_cppgen name change #164589

Closed

		@@ -421,7 +421,7 @@ def get_max_alignment(inductor_layout: Layout) -> int:
		offset = inductor_layout.offset

		def is_static_int(number):

	def is_static_int(number):
	def is_static_int(number: object) -> Type[int \| sympy.Integer]:

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