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A high-throughput and memory-efficient inference and serving engine for LLMs
https://docs.vllm.ai
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[Bug]: flash_attn # prefix-enabled attention case forward code maybe error? #6720

Open yangchengtest opened 3 months ago

yangchengtest commented 3 months ago

Your current environment

code review

🐛 Describe the bug

flash_attn.py forward func

code: else:

prefix-enabled attention

            assert prefill_meta.seq_lens is not None
            max_seq_len = max(prefill_meta.seq_lens)
            flash_attn_varlen_func(

in this case,flash_attn_varlen_func input params order may be wrong.

cu_seqlens_q=prefill_meta.query_start_loc, max_seqlen_q=prefill_meta.max_query_len, cu_seqlens_k=prefill_meta.seq_start_loc, max_seqlen_k=max_seq_len,

the input order should be cu_s,cu_q,max_s,max_q?

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