Support nullptr value of argument ptr_C for xe_array_epilogue
#541
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Hi @rolandschulz, in the main branch, for vanilla GEMM, a This PR fixes that issue. Thanks! |
Co-authored-by: rolandschulz <[email protected]>
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Problem
In a real-use case of GroupGEMM, we may not have any
Cmatrices. Whenbetais 0, passing a bogusptr_Cargument forxe_array_epilogue, such asptr_D, if they are the same dtype, still results in some wasteful compute, so for the default Group GEMM example (examples/04_bmg_grouped_gemm.cpp), there's a slowdown of ~0.1 TFLOPs.Solution
Preferable solution is to use
beta=0& a non-null value forptr_C, such asptr_D, e.g.static_cast<const ElementC**>((void*)ptr_D.get())even whenC&Dare not the same dtype becauseCtiles aren't actually used whenbetais0.However, in this implementation in this PR, if a user still wants to pass
nullptrargument forptr_C, thenCshould not be used irrespective of whatever thebetavalue is.Given that the aforementioned workaround doesn't result in a discernible performance penalty, I'm not sure if this PR makes sense.