On Wed, Feb 10, 2021 at 4:00 PM Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > On Wed, Feb 10, 2021 at 3:25 PM Bill Wendling <morbo@xxxxxxxxxx> wrote: > > > > This hashing function[1] produces better hash table bucket > > distributions. The original hashing function always produced zeros in > > the three least significant bits. > > > > The new hashing funciton gives a modest performance boost. > > > > Original New > > 0:11.41 0:11.38 > > 0:11.36 0:11.34 > > 0:11.35 0:11.26 > > ----------------------- > > Avg: 0:11.373 0:11.327 > > > > for a performance improvement of 0.4%. > > > > [1] From Numerical Recipes, 3rd Ed. 7.1.4 Random Hashes and Random Bytes > > > > Can you please also test with the one libbpf uses internally: > > return (val * 11400714819323198485llu) >> (64 - bits); > > ? > > Thanks! > It's giving me a running time of ~11.11s, which is even better. Would you like me to submit a patch? -bw
