4 ms·

64 characters with AVX-512? =)

• DannyBee 13y ago
  I didn't check to see if the instructions exist, but possibly :) You do start to hit two issues though as oyu increase the size of the skipping: 1. Alignment 2. If the average block comment/line is < 64 characters, you may lose more time performing the instruction and then counting the trailing zeros in the result to find the place it ended. I have no numbers to back up whether this matters, of course :)
  • pbsd 13y ago
    AVX-512 does not seem to have PMOVMSKB, which is how I assume it is being done with SSE2. There are other ways to skin that cat, but it's unclear whether they have any advantage over using AVX2 with VPMOVMSKB.
    • DannyBee 13y ago
      I posted a patch here: https://gist.github.com/dberlin/9867614 https://gist.github.com/dberlin/9867614 It adds AVX2 and SSE4.2 instruction support. It makes no discernible difference performance wise that i can find :)
      • jevinskie 13y ago
        Heh, awesome! I'll try it out today.