From: Shaun Thomas <sthomas@optionshouse.com>
To: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
To: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Cc: Graeme B. Bell <grb@skogoglandskap.no>
Subject: Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3
Date: Thu, 21 Aug 2014 09:14:56 -0500
Message-ID: <53F5FEE0.8040505@optionshouse.com> (raw)
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On 08/20/2014 06:14 PM, Mark Kirkwood wrote:
> Notwithstanding the above results, my workmate Matt made an interesting
> observation: the scaling graph for (our) 60 core box (HT off), looks
> just like the one for our 32 core box with HT *on*.
Hmm. I know this sounds stupid and unlikely, but has anyone actually
tested PostgreSQL on a system with more than 64 legitimate cores? The
work Robert Haas did to fix the CPU locking way back when showed
significant improvements up to 64, but so far as I know, nobody really
tested beyond that.
I seem to remember similar choking effects when pre-9.2 systems
encountered high CPU counts. I somehow doubt Intel would allow their HT
architecture to regress so badly from Nehalem, which is almost
3-generations old at this point. This smells like something in the
software stack, up to and including the Linux kernel.
--
Shaun Thomas
OptionsHouse, LLC | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@optionshouse.com
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To: pgsql-performance@postgresql.org
Cc: sthomas@optionshouse.com, mark.kirkwood@catalyst.net.nz, josh@agliodbs.com, grb@skogoglandskap.no
Subject: Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3
In-Reply-To: <53F5FEE0.8040505@optionshouse.com>
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