2 ms·

Apparently it only happens on P-cores, recent E-cores have a fast path for subnormals.

• rustybolt 8d ago
  That seems weird. They did throw extra hardware at it to speed it up for the efficient cores, but not for the performance cores?
  • deleted 8d ago
    [deleted]
  • cwzwarich 8d ago
    Probably different teams. Plus you can not underestimate the role that momentum plays in semiconductor engineering teams. If some respected person determined that subnormals are either Hard (tm) or not a Real Problem (tm), it will take a long time to correct this mistaken belief. I believe there have been some recent academic papers on FP implementation from the Intel E-Core team, which is a sign that they are a bit more with the times.
  • gpderetta 8d ago
    larger SIMD ALUs, which also have been around for longer?
  • Sesse__ 8d ago
    They are designed by different teams and have different ways of doing math. You could just as easily say “why are the efficiency cores wasting an extra cycle for each multiplication doing fixups of an uncommon case”. Fabian Giesen explains in more detail here: https://mastodon.gamedev.place/@rygorous/117277063419144390 https://mastodon.gamedev.place/@rygorous/117277063419144390