Re: Excessive context switching on SMP Xeons

From: Michael Adler <adler(at)pobox(dot)com>
To: Bill Montgomery <billm(at)lulu(dot)com>
Cc: Alan Stange <stange(at)rentec(dot)com>, Gaetano Mendola <mendola(at)bigfoot(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Excessive context switching on SMP Xeons
Date: 2004-10-07 18:15:38
Message-ID: 20041007181537.GA1693@pobox.com
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On Thu, Oct 07, 2004 at 11:48:41AM -0400, Bill Montgomery wrote:
> Alan Stange wrote:
>
> The same test on a Dell PowerEdge 1750, Dual Xeon 3.2 GHz, 512k cache,
> HT on, Linux 2.4.21-20.ELsmp (RHEL 3), 4GB memory, pg 7.4.5:
>
> Far less performance that the Dual Opterons with a low number of
> clients, but the gap narrows as the number of clients goes up. Anyone
> smarter than me care to explain?

You'll have to wait for someone smarter than you, but I will posit
this: Did you use a tmpfs filesystem like Alan? You didn't mention
either way. Alan did that as an attempt remove IO as a variable.

-Mike

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