Message-ID: <4DA35CF8.7050205@krogh.cc>
Date: Mon, 11 Apr 2011 21:56:40 +0200
From: Jesper Krogh <jesper@krogh.cc>
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To: pgsql-performance@postgresql.org
Subject: Re: Linux: more cores = less concurrency.
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On 2011-04-11 21:42, Glyn Astill wrote:
>
> I'll have to try with the synthetic benchmarks next then, but somethings definately going off here.  I'm seeing no disk activity at all as they're selects and all pages are in ram.
Well, if you dont have enough computations to be bottlenecked on the
cpu, then a 4 socket system is slower than a comparative 2 socket system
and a 1 socket system is even better.

If you have a 1 socket system, all of your data can be fetched from
"local" ram seen from you cpu, on a 2 socket, 50% of your accesses
will be "way slower", 4 socket even worse.

So the more sockets first begin to kick in when you can actually
use the CPU's or add in even more memory to keep your database
from going to disk due to size.

-- 
Jesper