Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XKBKY-0004rF-8k for pgsql-performance@arkaria.postgresql.org; Wed, 20 Aug 2014 19:13:58 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1XKBKX-0005Nr-L3 for pgsql-performance@arkaria.postgresql.org; Wed, 20 Aug 2014 19:13:57 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1XKBKW-0005Nl-QZ for pgsql-performance@postgresql.org; Wed, 20 Aug 2014 19:13:56 +0000 Received: from 01.zmailcloud.com ([192.198.85.104] helo=mx-out-1.zmailcloud.com) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XKBKT-0005QM-19 for pgsql-performance@postgresql.org; Wed, 20 Aug 2014 19:13:55 +0000 Received: from smtp.01.com (smtp.01.com [10.10.0.43]) by mx-out-1.zmailcloud.com (Postfix) with ESMTP id 490EA563FC3; Wed, 20 Aug 2014 14:13:52 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 3CEDB602EE; Wed, 20 Aug 2014 14:13:52 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id d6zK7LKhEwgY; Wed, 20 Aug 2014 14:13:52 -0500 (CDT) Received: from smtp.01.com (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 1B278602FC; Wed, 20 Aug 2014 14:13:52 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id F01ED602EE; Wed, 20 Aug 2014 14:13:51 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id wohHvE99JPTM; Wed, 20 Aug 2014 14:13:51 -0500 (CDT) Received: from [172.47.23.104] (70-36-143-82.dsl.dynamic.sonic.net [70.36.143.82]) by smtp-out-2.01.com (Postfix) with ESMTPSA id 5AE39601A8; Wed, 20 Aug 2014 14:13:51 -0500 (CDT) Message-ID: <53F4F36E.6050003@agliodbs.com> Date: Wed, 20 Aug 2014 12:13:50 -0700 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: pgsql-performance@postgresql.org CC: Mark Kirkwood , "Graeme B. Bell" Subject: Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3 References: <53ACB190.2030206@catalyst.net.nz> <53ECFD75.3060408@agliodbs.com> <53ED371D.109@catalyst.net.nz> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org Mark, all: So, this is pretty damming: Read-only test with HT ON: [pgtest@db ~]$ pgbench -c 20 -j 4 -T 600 -S bench starting vacuum...end. transaction type: SELECT only scaling factor: 30 query mode: simple number of clients: 20 number of threads: 4 duration: 600 s number of transactions actually processed: 47167533 tps = 78612.471802 (including connections establishing) tps = 78614.604352 (excluding connections establishing) Read-only test with HT Off: [pgtest@db ~]$ pgbench -c 20 -j 4 -T 600 -S bench starting vacuum...end. transaction type: SELECT only scaling factor: 30 query mode: simple number of clients: 20 number of threads: 4 duration: 600 s number of transactions actually processed: 82457739 tps = 137429.508196 (including connections establishing) tps = 137432.893796 (excluding connections establishing) On a read-write test, it's 10% faster with HT off as well. Further, from their production machine we've seen that having HT on causes the machine to slow down by 5X whenever you get more than 40 cores (as in 100% of real cores or 50% of HT cores) worth of activity. So we're definitely back to "If you're using PostgreSQL, turn off Hyperthreading". -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance