fix default window size for sparse_attn

[minminsun]

No description provided.

[LucasWilkinson]

@minminsun Sorry for the confusion but we will be making the lwilkinson/fa3-squashed branch the new main branch shortly (just wanted to hold off till after the release to do this to avoid issues that could potentially block the release), could you please make this PR to that branch instead of main?

(we had to do this this vllm-flash-attn had diverged too far from the upstream, apologies for the inconvenience)

[minminsun]

@minminsun Sorry for the confusion but we will be making the lwilkinson/fa3-squashed branch the new main branch shortly (just wanted to hold off till after the release to do this to avoid issues that could potentially block the release), could you please make this PR to that branch instead of main?

(we had to do this this vllm-flash-attn had diverged too far from the upstream, apologies for the inconvenience)

Hi @LucasWilkinson This PR is a bug fix for sparse_attn. It's OK for me to make the PR to branch lwilkinson/fa3-squashed, but I found that sparse_attn is not in that branch yet. Can we merge thie PR to main branch first, and, after that, cherry-pick the sparse_attn along with this change to that branch?

[LucasWilkinson]

but I found that sparse_attn is not in that branch yet.

hmmm it should be: https://github.com/vllm-project/flash-attention/blob/lwilkinson/fa3-squashed/csrc/flash_attn/flash_api_sparse.cpp

sorry its just in its own file now to reduce the diff with upstream

[minminsun]

but I found that sparse_attn is not in that branch yet.

hmmm it should be: https://github.com/vllm-project/flash-attention/blob/lwilkinson/fa3-squashed/csrc/flash_attn/flash_api_sparse.cpp

sorry its just in its own file now to reduce the diff with upstream

OK, I See. I will file another PR to the new branch. And I think the current main also needs this fix before it gets replaced.

[LucasWilkinson]

And I think the current main also needs this fix before it gets replaced.

Main is deprecated now, ill try to make sure the renaming happens next week 👍 we were just hesitant since we've been busy with the V1 and DeepSeek pushes so didn't want to break anything during such a crazy time, apologies