4 ms·

I don’t believe in the bright future of AVX512 tech, and I don’t have hardware either, my desktop PC has AMD Zen2 CPU. Here’s how I would do that in AVX2: http

• electricshampo1 6y ago
  (author here) Using srand(0) as in your gist; changing int8_t to char ; using int for sum: BM_hn 10155300 ns BM_avx512 9218652 ns ----- BM_avx512 9372319 ns BM_hn 10428792 ns Your code is getting ~18-19GB/s read bandwidth compared to roughly ~21GB/s for my code. I wonder how much of that is due to interleaved summing vs not compared to AVX512 vs AVX2.
  • Const-me 6y ago
    Interesting, thanks for the benchmark. Assuming none of us screwed up too badly, that gives us about 10% profit from AVX512 compared to AVX2. Not sure that’s a good enough win to justify vendor lock-in to Intel. P.S. int8_t is a typedef for char, that change was stylistic and should not affect performance whatsoever. I tend to avoid char data type for numbers, as opposed to characters. Update: you can try to make another AVX512 version with _mm512_sad_epu8 like I did for AVX2, instead of that integer dot product. I won’t be surprised to find out vpsadbw is faster than vpdpbusd, fundamentally addition is simpler than multiplication.
• schmide 6y ago
  I learned a lot from your code. Kudos