6 ms·

If you really care about performance, you could always compile on the target machine directly via -xhost [0] or whatever the flag is on your compiler. [0] http

• inetknght 7y ago
  In my case, it's GCC. The option is `-march=native -mtune=native`. The trick though is _describing_ the scalar operations in the language and getting the compiler to understand how to efficiently vectorize them. I couldn't get GCC to do it at the time (GCC-5 if I recall, though we deployed with GCC-6); maybe it was just inexperience on my part. But I ended up writing the intrinsics by hand. To be quite honest it was my first dive into SIMD and I thought it was rather fun to do.
  • ncmncm 7y ago
    -march=native implies -mtune=native. You can say -march=native -mtune=sandybridge, but there would be no point. You can say -march=sandybridge -mtune=native, usefully. It might go slower on a real sandybridge than if tuned for it, but would still work, and would go as fast as the smaller instruction mix allows on your build machine.
    • inetknght 7y ago
      I know this. I don't care. I use `-march-native -mtune=native` specifically to point other developers on the team to the two relevant compiler options. And if they don't look, nothing's lost.