From: | "Amonson, Paul D" <paul(dot)d(dot)amonson(at)intel(dot)com> |
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To: | Nathan Bossart <nathandbossart(at)gmail(dot)com> |
Cc: | Andres Freund <andres(at)anarazel(dot)de>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, "Shankaran, Akash" <akash(dot)shankaran(at)intel(dot)com>, Noah Misch <noah(at)leadboat(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: | 2024-03-14 19:50:46 |
Message-ID: | BL1PR11MB53042473B7B53B96E43648A7DC292@BL1PR11MB5304.namprd11.prod.outlook.com |
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Lists: | pgsql-hackers |
> -----Original Message-----
> From: Nathan Bossart <nathandbossart(at)gmail(dot)com>
> Sent: Monday, March 11, 2024 6:35 PM
> To: Amonson, Paul D <paul(dot)d(dot)amonson(at)intel(dot)com>
> Thanks. There's no need to wait to post the AVX portion. I recommend using
> "git format-patch" to construct the patch set for the lists.
After exploring git format-patch command I think I understand what you need. Attached.
> > What exactly do you suggest here? I am happy to always call either
> > pg_popcount32() or pg_popcount64() with the understanding that it may
> > not be optimal, but I do need to know which to use.
>
> I'm recommending that we don't change any of the code in the pg_popcount()
> function (which is renamed to pg_popcount_slow() in your v6 patch). If
> pointers are 8 or more bytes, we'll try to process the buffer in 64-bit chunks.
> Else, we'll try to process it in 32-bit chunks. Any remaining bytes will be
> processed one-by-one.
Ok, we are on the same page now. :) It is already fixed that way in the refactor patch #1.
As for new performance numbers: I just ran a full suite like I did earlier in the process. My latest results an equivalent to a pgbench scale factor 10 DB with the target column having varying column widths and appropriate random data are 1.2% improvement with a 2.2% Margin of Error at a 98% confidence level. Still seeing improvement and no regressions.
As stated in the previous separate chain I updated the code removing the extra "extern" keywords.
Thanks,
Paul
Attachment | Content-Type | Size |
---|---|---|
v8-0001-Refactor-POPCNT-code-refactored-for-future-accelerat.patch | application/octet-stream | 8.4 KB |
v8-0002-Feat-Add-AVX-512-POPCNT-support-initial-checkin.patch | application/octet-stream | 24.5 KB |
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