[fix][cpu] fix prefill attention in CPU attention backend #27035
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Hi @bigPYJ1151 - would you be able to review this please? |
- Disables prefix caching because prefill attention can't handle paged KV cache - Fixes Q/K/V used during prefill on mixed prefill/decode requests Signed-off-by: Fadi Arafeh <[email protected]>
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This pull request introduces fixes for prefill attention in the CPU attention backend. The changes correctly handle mixed prefill/decode requests by adjusting the starting indices for Q/K/V tensors and correctly slicing sequence lengths for prefill requests. Additionally, it disables prefix caching on certain CPU architectures where it is not supported. The changes are logical, well-implemented, and address the described issues effectively. I have no major concerns.
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@bigPYJ1151 do you think you can help look at this? not that well versed in the CPU backend |
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After some tests I found even set |
Signed-off-by: Fadi Arafeh <[email protected]>
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Thanks for your review @bigPYJ1151 |
bigPYJ1151
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[fix][cpu] fix prefill attention in CPU attention backend
Purpose
Fixes #27034
Test Plan
test script attached to #27034
Test Result
Output of test script attached to #27034 is same when prompts are batched and when prompts are ran one at a time
Essential Elements of an Effective PR Description Checklist
supported_models.mdandexamplesfor a new model.