RE: Proposal for Updating CRC32C with AVX-512 Algorithm.

Here are the latest set of patches built on top of your patch to use __attribute__(target) for AVX-512 popcount. Couple of changes made:

(1) The SSE42 and AVX-512 CRC32C also use function attributes to build with ISA specific flag.
(2) Fixes a bug in the earlier version of patch which had performance regressions on SKX because of a bug in the compile time and runtime checks involving the AVX-512 CRC32C code.

Raghuveer

> -----Original Message-----
> From: Nathan Bossart <nathandbossart(at)gmail(dot)com>
> Sent: Friday, October 18, 2024 9:32 AM
> To: Devulapalli, Raghuveer <raghuveer(dot)devulapalli(at)intel(dot)com>
> Cc: Bruce Momjian <bruce(at)momjian(dot)us>; Alvaro Herrera <alvherre(at)alvh(dot)no-
> ip.org>; Andres Freund <andres(at)anarazel(dot)de>; pgsql-
> hackers(at)lists(dot)postgresql(dot)org; Shankaran, Akash <akash(dot)shankaran(at)intel(dot)com>
> Subject: Re: Proposal for Updating CRC32C with AVX-512 Algorithm.
>
> On Tue, Oct 08, 2024 at 08:19:27PM +0000, Devulapalli, Raghuveer wrote:
> > Hi all, I'm currently in the process of reviewing and analyzing Paul's
> > patch. In the meantime, I'm open to addressing any questions or
> > feedback you may have.
>
> I've proposed a patch to move the existing AVX-512 code in Postgres to use
> __attribute__((target("..."))) instead of per-translation-unit compiler flags [0]. We
> should likely do something similar for this one.
>
> [0] https://postgr.es/m/ZxAqRG1-8fJLMRUY%40nathan
>
> --
> nathan