| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | "Shankaran, Akash" <akash(dot)shankaran(at)intel(dot)com> |
| Cc: | Nathan Bossart <nathandbossart(at)gmail(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, "Amonson, Paul D" <paul(dot)d(dot)amonson(at)intel(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Popcount optimization using AVX512 |
| Date: | 2024-01-26 06:42:33 |
| Message-ID: | 202401260642.3rxzgb2xrhkl@alvherre.pgsql |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2024-Jan-25, Alvaro Herrera wrote:
> Finally, the matter of using ifunc as proposed by Noah seems to be still
> in the air, with no patches offered for the popcount family.
Oh, I just realized that the patch as currently proposed is placing the
optimized popcount code in the path that does not require going through
a function pointer. So the performance increase is probably coming from
both avoiding jumping through the pointer as well as from the improved
instruction.
This suggests that finding a way to make the ifunc stuff work (with good
performance) is critical to this work.
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"The ability of users to misuse tools is, of course, legendary" (David Steele)
https://postgr.es/m/11b38a96-6ded-4668-b772-40f992132797@pgmasters.net
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Andrey M. Borodin | 2024-01-26 06:44:02 | Re: Transaction timeout |
| Previous Message | David G. Johnston | 2024-01-26 06:33:22 | Re: Small fix on COPY ON_ERROR document |