From: Scott Carey <scott@richrelevance.com>
To: Gregory Stark <stark@enterprisedb.com>
To: Jignesh K. Shah <J.K.Shah@Sun.COM>
Cc: Simon Riggs <simon@2ndQuadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Proposal of tunable fix for scalability of 8.4
Date: Wed, 18 Mar 2009 14:16:01 -0700
Message-ID: <C5E6B2A1.37BF%scott@richrelevance.com> (raw)
In-Reply-To: <87iqm7f4gd.fsf@oxford.xeocode.com>
On 3/18/09 4:36 AM, "Gregory Stark" <stark@enterprisedb.com> wrote:
>
>
> "Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:
>
>> In next couple of weeks I plan to test the patch on a different x64 based
>> system to do a sanity testing on lower number of cores and also try out other
>> workloads ...
>
> I'm actually more interested in the large number of cores but fewer processes
> and lower max_connections. If you set max_connections to 64 and eliminate the
> wait time you should, in theory, be able to get 100% cpu usage. It would be
> very interesting to track down the contention which is preventing that.
My previous calculation in this thread showed that even at 0 wait time, the
client seems to introduce ~3ms wait time overhead on average. So it takes
close to 128 threads in each test to stop the linear scaling since the
average processing time seems to be about ~3ms.
Either that, or the tests actually are running on a system capable of 128
threads.
>
> --
> Gregory Stark
> EnterpriseDB http://www.enterprisedb.com
> Ask me about EnterpriseDB's PostGIS support!
>
> -
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To: pgsql-performance@postgresql.org
Cc: scott@richrelevance.com, stark@enterprisedb.com, J.K.Shah@Sun.COM, simon@2ndQuadrant.com, tgl@sss.pgh.pa.us, Kevin.Grittner@wicourts.gov
Subject: Re: Proposal of tunable fix for scalability of 8.4
In-Reply-To: <C5E6B2A1.37BF%scott@richrelevance.com>
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