From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
To: David Rowley <david.rowley@2ndquadrant.com>
To: Jeison Bedoya Delgado <jeisonb@audifarma.com.co>
Cc: pgsql-performance@postgresql.org
Subject: Re: hyperthreadin low performance
Date: Tue, 21 Jul 2015 21:07:46 +1200
Message-ID: <55AE0BE2.3040603@catalyst.net.nz> (raw)
In-Reply-To: <CAKJS1f_pAPeff0yRg_LCg28p=dAfvURf-sTVH9NtP0vhF=Xqcg@mail.gmail.com>
References: <55ADB586.2010406@audifarma.com.co>
<CAKJS1f_pAPeff0yRg_LCg28p=dAfvURf-sTVH9NtP0vhF=Xqcg@mail.gmail.com>
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On 21/07/15 20:04, David Rowley wrote:
> On 21 July 2015 at 14:59, Jeison Bedoya Delgado
> <jeisonb@audifarma.com.co <mailto:jeisonb@audifarma.com.co>> wrote:
>
> hi everyone,
>
> Recently update a database to machine with RHEL7, but i see that the
> performance is betther if the hyperthreading tecnology is
> deactivated and use only 32 cores.
>
> is normal that the machine performance is better with 32 cores that
> 64 cores?.
>
>
> You might be interested in
> http://www.postgresql.org/message-id/53F4F36E.6050003@agliodbs.com
>
However I do wonder if we have been misinterpreting these tests. We tend
to assume the position of "see hyperthreading is bad, switch it off".
The linked post under the one above:
http://www.postgresql.org/message-id/53ED371D.109@catalyst.net.nz
shows that 60 core (no hyperthreading) performance is also pessimal,
leading me to conclude that *perhaps* it is simply the number of cores
that is the problem - particularly as benchmark results for single
socket cpus clearly show hyperthreading helps performance...
Regards
Mark
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To: pgsql-performance@postgresql.org
Cc: mark.kirkwood@catalyst.net.nz, david.rowley@2ndquadrant.com, jeisonb@audifarma.com.co
Subject: Re: hyperthreadin low performance
In-Reply-To: <55AE0BE2.3040603@catalyst.net.nz>
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