Em Fri, Feb 12, 2021 at 09:37:22AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Feb 12, 2021 at 12:01:04AM -0800, Bill Wendling escreveu:
> > 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 function gives a
> > modest performance boost:
>
> Some tidbits:
>
> You forgot to CC Andrii and also to add this, which I'm doing now:
>
> Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
>
> :-)
See below the full cset, that will go public after some more tests here.
- Arnaldo
commit 9fecc77ed82d429fd3fe49ba275465813228e617 (HEAD -> master)
Author: Bill Wendling <morbo@xxxxxxxxxx>
Date: Fri Feb 12 00:01:04 2021 -0800
dwarf_loader: Use a better hashing function, from libbpf
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 function gives a
modest performance boost:
Original: 0:11.373s
New: 0:11.110s
for a performance improvement of ~2%.
[1] From the hash function used in libbpf.
Committer notes:
Bill found the suboptimality of the hash function being used, Andrii
suggested using the libbpf one, which ended up being better.
Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>
Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Cc: bpf@xxxxxxxxxxxxxxx
Cc: dwarves@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
