gemm/dgemm: add a way for an arch kernel to specify preferred sizes #1846
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fenrus75
commented
Nov 1, 2018
fenrus75
commented
in the threading code there are cases where N or M can become 0, and the optimized beta code did not handle this well, leading to a crash during the audit for the crash a few edge conditions on the if statements were found and fixed as well
The current gemm threading code can make very unfortunate choices, for example on my 10 core system a 1024x1024x1024 matrix multiply ends up chunking into blocks of 102... which is not a vector friendly size and performance ends up horrible. this patch adds a helper define where an architecture can specify a preference for size multiples. This is different from existing defines that are minimum sizes and such. The performance increase with this patch for the 1024x1024x1024 sgemm is 2.3x (!!)
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Interesting to say the least... but I expect the net effect is smaller on more mundane AVX2 hardware ? |
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only sort of. lets say 10 core (20 thread) system, 1024x1024x1024 matrix. so that is a 32 wide stride, then a 16 (both can still be performant) then a 2 and a 1 by doing similar rounding up to nice multiples, this same thread does 2 "K loops" of 32 each instead of 4 "K loops" |
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A small nit-pick. It should be preferred no? |
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