[CuTe] [Xe] Separate make_block_2d_copy_{C,D} APIs for loads/stores #572
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rolandschulz
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Oct 21, 2025
This was referenced Oct 22, 2025
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rolandschulz
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Modify 00_bmg_gemm to include new mma and copy atoms (#477). 00_bmg_gemm combines two parts: mma and epilogue. To add new atom changes, we need to update both parts since they currently use old atoms. As starting we will: > Keep CollectiveEpilogue unchanged for now > Only modify CollectiveMma first Old Atom: Problem Size: 5120x4096x4096x1 Cutlass GEMM Performance: [96.448]TFlop/s (1.7813)ms New Atom: Problem Size: 5120x4096x4096x1 Cutlass GEMM Performance: [97.259]TFlop/s (1.7664)ms Also depend on new copy_c/copy_d apis for load/store #572 --------- Co-authored-by: Anamika Chatterjee <[email protected]>
sanchitintel
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#573 reported some performance regressions when this API is used instead of manually selecting copy atoms (or compared to the legacy API) .
But performance in examples/cute/tutorial/xe_gemm.cpp example wasn't adversely affected by these changes, so the performance degradation observed in #573 is likely to be unrelated to this PR (except if the perf degradation is due to loading the canonical ).C matrix in #573, but if beta is 0, would the compiler still load C? Not sure about that part
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Currently
make_block_2d_copy_Calways selects a block 2D store, but we really need separate APIs for C (loads) and D (stores). The default value type can also be different, in case of MMA atoms with different C/D types.This PR introduces C/D APIs. Some APIs are common between C/D, and are named
make_block_2d_copy_CDto avoid duplication.