From: Andrea Suisani <sickpig@opinioni.net>
To: Craig James <cjames@emolecules.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Two identical systems, radically different performance
Date: Thu, 11 Oct 2012 16:14:11 +0200
Message-ID: <5076D433.7090605@opinioni.net> (raw)
In-Reply-To: <CAFwQ8rcyCKcoeEn62_QHMRSmJM03ULERtW6_R=3TaO0twOEV9A@mail.gmail.com>
References: <CAFwQ8rcvw4mSoJ9q+ouONCeB9dg1T9gAUV5J27MpVZrehRHayQ@mail.gmail.com>
<CAFwQ8rfm2AcuoFHDfBLA_hg7ffbsYNsrsaJPDqcOeGqaVW02OQ@mail.gmail.com>
<CAFwQ8rcyCKcoeEn62_QHMRSmJM03ULERtW6_R=3TaO0twOEV9A@mail.gmail.com>
On 10/09/2012 01:40 AM, Craig James wrote:
> Nobody has commented on the hyperthreading question yet ... does it really matter? The old (fast) server has hyperthreading disabled, and the new (slower) server has hyperthreads enabled.
>
> If hyperthreading is definitely NOT an issue, it will save me a trip to the co-lo facility.
sorry to come late to the party, but being in a similar condition
I've googled a bit and I've found a way to disable hyperthreading without
the need to reboot the system and entering the bios:
echo 0 >/sys/devices/system/node/node0/cpuX/online
where X belongs to 1..(#cores * 2) if hyperthreading is enabled
(cpu0 can't be switched off).
didn't try myself on live system, but I definitely will
as soon as I have a new machine to test.
Andrea
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To: pgsql-performance@postgresql.org
Cc: sickpig@opinioni.net, cjames@emolecules.com
Subject: Re: Two identical systems, radically different performance
In-Reply-To: <5076D433.7090605@opinioni.net>
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