Horton

Re: Possible performance regression in version 10.1 with pgbench read-write tests.

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Mithun Cy <mithun.cy@enterprisedb.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Amit Kapila <amit.kapila16@gmail.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-07-24T23:08:20Z
Lists: pgsql-hackers 
On Mon, Jul 23, 2018 at 10:06 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> Here's an attempt to use existing style better: a union, like
> LWLockPadded and WALInsertLockPadded.  I think we should back-patch to
> 10.  Thoughts?

Pushed to 10, 11, master.

It's interesting that I could see a further ~12% speedup by using VM
page-size stride on that 8 socket machine, but that's something to
look at another day.  The PG_CACHE_LINE_SIZE padding change gets us
back to approximately where we were in 9.6.

/me . o O ( Gee, it'd be really nice to see this change on a graph on
a web page that tracks a suite of tests on a farm of interesting
machines on each branch over time. )

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

Commits

  1. Pad semaphores to avoid false sharing.