Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id 8E5D81337990 for ; Tue, 12 Apr 2011 13:59:10 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 13574-05 for ; Tue, 12 Apr 2011 16:59:02 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from smtp4-g21.free.fr (smtp4-g21.free.fr [212.27.42.4]) by mail.postgresql.org (Postfix) with ESMTP id EBB3313364DE for ; Tue, 12 Apr 2011 13:58:59 -0300 (ADT) Received: from [192.168.0.18] (unknown [78.237.44.8]) by smtp4-g21.free.fr (Postfix) with ESMTP id 0AAFD4C848D for ; Tue, 12 Apr 2011 18:58:54 +0200 (CEST) Message-ID: <4DA484C7.7020803@club-internet.fr> Date: Tue, 12 Apr 2011 18:58:47 +0200 From: "F. BROUARD / SQLpro" Organization: sqlpro.developpez.com User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 CC: pgsql-performance@postgresql.org Subject: Re: Linux: more cores = less concurrency. References: <860299.67368.qm@web26003.mail.ukl.yahoo.com> In-Reply-To: <860299.67368.qm@web26003.mail.ukl.yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.878 tagged_above=-10 required=5 tests=BAYES_00=-1.9, MISSING_HEADERS=1.021, RCVD_IN_DNSWL_NONE=-0.0001, RFC_ABUSE_POST=0.001 X-Spam-Level: X-Archive-Number: 201104/166 X-Sequence-Number: 43228 Hi, I think that a NUMA architecture machine can solve the problem.... A + Le 11/04/2011 15:04, Glyn Astill a écrit : > > Hi Guys, > > I'm just doing some tests on a new server running one of our heavy select functions (the select part of a plpgsql function to allocate seats) concurrently. We do use connection pooling and split out some selects to slony slaves, but the tests here are primeraly to test what an individual server is capable of. > > The new server uses 4 x 8 core Xeon X7550 CPUs at 2Ghz, our current servers are 2 x 4 core Xeon E5320 CPUs at 2Ghz. > > What I'm seeing is when the number of clients is greater than the number of cores, the new servers perform better on fewer cores. > > Has anyone else seen this behaviour? I'm guessing this is either a hardware limitation or something to do with linux process management / scheduling? Any idea what to look into? > > My benchmark utility is just using a little .net/npgsql app that runs increacing numbers of clients concurrently, each client runs a specified number of iterations of any sql I specify. > > I've posted some results and the test program here: > > http://www.8kb.co.uk/server_benchmarks/ > > -- Frédéric BROUARD - expert SGBDR et SQL - MVP SQL Server - 06 11 86 40 66 Le site sur le langage SQL et les SGBDR : http://sqlpro.developpez.com Enseignant Arts & Métiers PACA, ISEN Toulon et CESI/EXIA Aix en Provence Audit, conseil, expertise, formation, modélisation, tuning, optimisation *********************** http://www.sqlspot.com *************************