Received: from makus.postgresql.org ([98.129.198.125]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TW5l5-0006CU-PI for pgsql-performance@postgresql.org; Wed, 07 Nov 2012 13:33:31 +0000 Received: from server13-scl.nuevasync.com ([64.13.138.208] helo=mail.nuevasync.com) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TW5l3-0000BG-28 for pgsql-performance@postgresql.org; Wed, 07 Nov 2012 13:33:30 +0000 Received: from [192.168.65.253] (unknown [69.51.127.178]) by mail.nuevasync.com (Postfix) with ESMTP id 1A9B1458006 for ; Wed, 7 Nov 2012 06:33:27 -0700 (MST) Message-ID: <509A631F.2010507@boreham.org> Date: Wed, 07 Nov 2012 06:33:19 -0700 From: David Boreham User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: pgsql-performance@postgresql.org Subject: Re: HT on or off for E5-26xx ? References: <5099D5FA.90802@boreham.org> <5099E094.9010703@catalyst.net.nz> In-Reply-To: <5099E094.9010703@catalyst.net.nz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201211/83 X-Sequence-Number: 48449 On 11/6/2012 9:16 PM, Mark Kirkwood wrote: > > > I've been benchmarking a E5-4640 (4 socket) and hyperthreading off > gave much better scaling behaviour in pgbench (gentle rise and flatten > off), whereas with hyperthreading on there was a dramatic falloff > after approx number clients = number of (hyperthreaded) cpus. The box > is intended to be a pure db server, so we are running with > hyperthreading off. It looks like this syndrome is not observed on my box, likely due to the much lower number of cores system-wide (12). I see pgbench tps increase nicely until #threads/clients == #cores, then plateau. I tested up to 96 threads btw. We're waiting on more memory modules to arrive. I'll post some test results once we have all 4 memory banks populated.