Date: Fri, 15 Mar 2024 10:06:11 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: "Amonson, Paul D" <paul.d.amonson@intel.com>
Cc: Andres Freund <andres@anarazel.de>,
	Alvaro Herrera <alvherre@alvh.no-ip.org>,
	"Shankaran, Akash" <akash.shankaran@intel.com>,
	Noah Misch <noah@leadboat.com>, Tom Lane <tgl@sss.pgh.pa.us>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Subject: Re: Popcount optimization using AVX512
Message-ID: <20240315150611.GA3495582@nathanxps13>
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On Thu, Mar 14, 2024 at 07:50:46PM +0000, Amonson, Paul D wrote:
> 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.

Which test suite did you run?  Those numbers seem potentially
indistinguishable from noise, which probably isn't great for such a large
patch set.

I ran John Naylor's test_popcount module [0] with the following command on
an i7-1195G7:

	time psql postgres -c 'select drive_popcount(10000000, 1024)'

Without your patches, this seems to take somewhere around 8.8 seconds.
With your patches, it takes 0.6 seconds.  (I re-compiled and re-ran the
tests a couple of times because I had a difficult time believing the amount
of improvement.)

[0] https://postgr.es/m/CAFBsxsE7otwnfA36Ly44zZO%2Bb7AEWHRFANxR1h1kxveEV%3DghLQ%40mail.gmail.com

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com