Horton

Re: [HACKERS] kqueue

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Torsten Zuehlsdorff <mailinglists@toco-domains.de>
Cc: Keith Fiske <keith@omniti.com>, Matteo Beccati <php@beccati.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Heikki Linnakangas <hlinnaka@iki.fi>, Marko Tiikkaja <marko@joh.to>, Alvaro Herrera <alvherre@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Noah Misch <noah@leadboat.com>
Date: 2017-12-05T11:53:22Z
Lists: pgsql-hackers

Attachments

On Thu, Jun 22, 2017 at 7:19 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> I don't plan to resubmit this patch myself, but I was doing some
> spring cleaning and rebasing today and I figured it might be worth
> quietly leaving a working patch here just in case anyone from the
> various BSD communities is interested in taking the idea further.

Since there was a mention of kqueue on -hackers today, here's another
rebase.  I got curious just now and ran a very quick test on an AWS 64
vCPU m4.16xlarge instance running image "FreeBSD
11.1-STABLE-amd64-2017-08-08 - ami-00608178".  I set shared_buffers =
10GB and ran pgbench approximately the same way Heikki and Keith did
upthread:

pgbench -i -s 200 postgres
pgbench -M prepared  -j 6 -c 6 -S postgres -T60 -P1
pgbench -M prepared  -j 12 -c 12 -S postgres -T60 -P1
pgbench -M prepared  -j 24 -c 24 -S postgres -T60 -P1
pgbench -M prepared  -j 36 -c 36 -S postgres -T60 -P1
pgbench -M prepared  -j 48 -c 48 -S postgres -T60 -P1

The TPS numbers I got (including connections establishing) were:

clients    master    patched
      6   146,215    147,535 (+0.9%)
     12   273,056    280,505 (+2.7%)
     24   360,751    369,965 (+2.5%)
     36   413,147    420,769 (+1.8%)
     48   416,189    444,537 (+6.8%)

The patch appears to be doing something positive on this particular
system and that effect was stable over a few runs.

-- 
Thomas Munro
http://www.enterprisedb.com

Commits

  1. Add kqueue(2) support to the WaitEventSet API.

  2. Add WL_EXIT_ON_PM_DEATH pseudo-event.

  3. Be conservative about alignment requirements of struct epoll_event.

  4. Make idle backends exit if the postmaster dies.