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Fix 2pass sdpa on < M2 - #3099
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angeloskath
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Feb 5, 2026
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Thanks for the fix.
I assume there isn't a perf regression...
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No but at first I tried getting rid of the blocks function constant entirely from the first pass as well and there was a very note-able regression.. which was unexpected. |
This was referenced Aug 11, 2026
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Closes ml-explore/mlx-lm#844
Honestly I think this is a lower level issue. For some reason using blocks = 128 when blocks is a function constant makes the kernel support < 1024 threads per thread group. Other values (64, 256, etc) do not have that issue. This is just for bfloat16 on M1 and M2 🤷♂️