| From: | Nathan Bossart <nathandbossart(at)gmail(dot)com> |
|---|---|
| To: | Ants Aasma <ants(dot)aasma(at)cybertec(dot)at> |
| Cc: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, "Amonson, Paul D" <paul(dot)d(dot)amonson(at)intel(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, David Rowley <dgrowleyml(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, "Shankaran, Akash" <akash(dot)shankaran(at)intel(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, 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: | 2024-04-01 21:31:40 |
| Message-ID: | 20240401213140.GA2362108@nathanxps13 |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, Apr 02, 2024 at 12:11:59AM +0300, Ants Aasma wrote:
> What about using the masking capabilities of AVX-512 to handle the
> tail in the same code path? Masked out portions of a load instruction
> will not generate an exception. To allow byte level granularity
> masking, -mavx512bw is needed. Based on wikipedia this will only
> disable this fast path on Knights Mill (Xeon Phi), in all other cases
> VPOPCNTQ implies availability of BW.
Sounds promising. IMHO we should really be sure that these kinds of loads
won't generate segfaults and the like due to the masked-out portions. I
searched around a little bit but haven't found anything that seemed
definitive.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Thomas Munro | 2024-04-01 21:45:17 | Re: pg_combinebackup --copy-file-range |
| Previous Message | Imseih (AWS), Sami | 2024-04-01 21:29:28 | Re: Psql meta-command conninfo+ |