sgl-flash-attn3: switch to torch stable ABI by adarshxs · Pull Request #1054 · huggingface/kernels-community

adarshxs · 2026-07-31T16:19:31Z

What does this PR do?

Ports sgl-flash-attn3 to the Torch stable ABI.

Motivation

Changes

Testing

Checklist

This PR is linked to an issue that was discussed and approved
I have tested these changes locally
New/changed functionality has test coverage
LLM disclosure:
- I did not use an LLM to create this PR.
- I used and LLM for assistance while creating this PR.
- This PR was mostly or completely generated by an LLM.

danieldk · 2026-08-03T07:12:30Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-03T07:12:55Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: fb414e7405b003e283a865d911fe9fa7bd95bda4
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/30792821719

sayakpaul · 2026-08-06T03:27:29Z

@adarshxs could you look into the build failures?

ptxas 13.2 hits an internal compiler error (C7907) when building the sm90 bf16 aggregators (flash_fwd_hdimall_bf16{,_softcap}_sm90.cu). CUDA 12.8 and 13.0 build cleanly and the 13.0 build is backwards compatible, so cap the matrix at 13.0.

sayakpaul · 2026-08-10T12:08:52Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-10T12:09:14Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: 7d5a87fc73ff3df5cf6a155ca66482623b6a456d
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/31386682904

adarshxs · 2026-08-11T14:33:35Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-11T14:33:50Z

I can only run /kernel-bot build-and-stage for users with write or admin repository permission.

sayakpaul · 2026-08-11T14:36:57Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-11T14:37:14Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: 7d5a87fc73ff3df5cf6a155ca66482623b6a456d
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/31502533569

sayakpaul · 2026-08-11T14:38:58Z

@adarshxs could we also do #1032?

adarshxs · 2026-08-12T05:24:48Z

@sayakpaul already done in this

sayakpaul · 2026-08-12T06:15:36Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-12T06:15:54Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: 6197185e86f45802082545c29a04d1bcff291c1e
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/31569368036

sayakpaul · 2026-08-15T14:58:05Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-15T14:58:19Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: 6197185e86f45802082545c29a04d1bcff291c1e
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/31891391510

sayakpaul · 2026-08-20T05:43:32Z

Blocked on #1087

sayakpaul · 2026-08-20T15:21:27Z

/kernel-bot build-and-stage sgl-flash-attn3

sayakpaul · 2026-08-20T15:23:34Z

/kernel-bot build-and-stage sgl-flash-attn3

sayakpaul · 2026-08-20T15:28:30Z

/kernel-bot build-and-stage sgl-flash-attn3

github-actions · 2026-08-20T15:28:42Z

Build request processed.

Command: /kernel-bot build-and-stage sgl-flash-attn3
Mode: build and stage
Target branch: pr-1054
PR head SHA: 87763f88cb39a20473eab835c8435ee85c790b76
Workflows: build.yaml, build-mac.yaml, build-windows.yaml

Dispatched (1):

sgl-flash-attn3 (build.yaml): https://github.com/huggingface/kernels-community/actions/runs/32386364592

sayakpaul · 2026-08-21T04:03:42Z

https://huggingface.co/kernels/kernels-staging/sgl-flash-attn3/tree/pr-1054 seems to be working. aarch64 is still failing :/

adarshxs could you test using https://huggingface.co/kernels/kernels-staging/sgl-flash-attn3/tree/pr-1054? I think we will need to provide revision="pr-1054" while loading the kernel.

sayakpaul · 2026-08-24T11:19:21Z

@adarshxs a gentle ping

danieldk · 2026-08-27T19:01:47Z

I think the aarch64 builds never worked?

https://huggingface.co/kernels/kernels-community/sgl-flash-attn3/tree/v1/build

init

fb414e7

github-actions Bot added the chore Version bumps, releases, misc maintenance label Jul 31, 2026

adarshxs mentioned this pull request Aug 10, 2026

sgl-flash-attn3: build against the Torch stable ABI #1043

Open

adarshxs and others added 2 commits August 10, 2026 16:25

Merge branch 'main' into sgl-stable-abi

45b8372

sgl-flash-attn3: pin CUDA maxver to 13.0

7d5a87f

ptxas 13.2 hits an internal compiler error (C7907) when building the sm90 bf16 aggregators (flash_fwd_hdimall_bf16{,_softcap}_sm90.cu). CUDA 12.8 and 13.0 build cleanly and the 13.0 build is backwards compatible, so cap the matrix at 13.0.

Merge branch 'main' into sgl-stable-abi

6197185

Merge branch 'main' into sgl-stable-abi

87763f8

Merge branch 'main' into sgl-stable-abi

70eb8a0

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