Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XKpoy-0000Ao-PG for pgsql-performance@arkaria.postgresql.org; Fri, 22 Aug 2014 14:28:04 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1XKpoy-0002zd-3d for pgsql-performance@arkaria.postgresql.org; Fri, 22 Aug 2014 14:28:04 +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 1XKpou-0002sr-IW for pgsql-performance@postgresql.org; Fri, 22 Aug 2014 14:28:00 +0000 Received: from mail.anarazel.de ([217.115.131.40]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XKpor-0004EO-15 for pgsql-performance@postgresql.org; Fri, 22 Aug 2014 14:27:58 +0000 Received: from intern.anarazel.de (unknown [89.204.154.164]) (Authenticated sender: andres@anarazel.de) by mail.anarazel.de (Postfix) with ESMTPSA id 17EA4560009; Fri, 22 Aug 2014 16:27:52 +0200 (CEST) Date: Fri, 22 Aug 2014 16:02:23 +0200 From: Andres Freund To: Josh Berkus Cc: Bruce Momjian , pgsql-performance@postgresql.org, Mark Kirkwood , "Graeme B. Bell" Subject: Re: Turn off Hyperthreading! WAS: 60 core performance with 9.3 Message-ID: <20140822140223.GP17406@alap3.anarazel.de> References: <53ACB190.2030206@catalyst.net.nz> <53ECFD75.3060408@agliodbs.com> <53ED371D.109@catalyst.net.nz> <53F4F36E.6050003@agliodbs.com> <20140821024036.GB26706@momjian.us> <53F65E62.3020909@agliodbs.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53F65E62.3020909@agliodbs.com> X-Pg-Spam-Score: -1.8 (-) 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 On 2014-08-21 14:02:26 -0700, Josh Berkus wrote: > On 08/20/2014 07:40 PM, Bruce Momjian wrote: > > Not sure how you can make such a blanket statement when so many people > > have tested and shown the benefits of hyper-threading. > > Actually, I don't know that anyone has posted the benefits of HT. > Link? There's definitely cases where it can help. But it's highly workload *and* hardware dependent. > OS is RHEL with 2.6.32-431.3.1.el6.x86_64. > > I've emailed a kernel hacker who works at Intel for comment; for one > thing, I'm wondering if the older kernel version is a problem for a > system like this. I'm not sure if it has been backported by redhat, but there definitely have been significant improvement in SMT aware scheduling after vanilla 2.6.32. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance