fix race condition bug in cute _flash_attn_fwd in multiple gpu env #1793
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I'm not sure it's "race condition", I suspect it just launches the kernel on cuda device 0 even when the data is on cuda device 1 |
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I see. When do you expect we will have Blackwell support for _flash_attn_bwd? |
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3-4 weeks |
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In multi-gpu runs, the cute implementation of _flash_attn_fwd returns incorrect values for gpu != 0. This can be fixed with torch.cuda.device context manager as sugguested issue1782: