Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1XM2Wg-00019P-7N for pgsql-performance@arkaria.postgresql.org; Mon, 25 Aug 2014 22:14:10 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1XM2We-0005z9-Uj for pgsql-performance@arkaria.postgresql.org; Mon, 25 Aug 2014 22:14:08 +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 1XM2Wc-0005ys-Km for pgsql-performance@postgresql.org; Mon, 25 Aug 2014 22:14:06 +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 1XM2WZ-0007Lz-CF for pgsql-performance@postgresql.org; Mon, 25 Aug 2014 22:14:04 +0000 Received: from smtp.01.com (smtp.01.com [10.10.0.43]) by mx-out-1.zmailcloud.com (Postfix) with ESMTP id 631A15645D3; Mon, 25 Aug 2014 17:14:02 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id 50F7FA05D3; Mon, 25 Aug 2014 17:14:02 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-1.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-1.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id g5AN8H4iCk0j; Mon, 25 Aug 2014 17:14:02 -0500 (CDT) Received: from smtp.01.com (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id 239C6A05CE; Mon, 25 Aug 2014 17:14:02 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id ED6D1A05D3; Mon, 25 Aug 2014 17:14:01 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-1.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-1.01.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 0Cc_OGmjPreI; Mon, 25 Aug 2014 17:14:01 -0500 (CDT) Received: from [172.47.23.104] (70-36-143-82.dsl.dynamic.sonic.net [70.36.143.82]) by smtp-out-1.01.com (Postfix) with ESMTPSA id 24D11A05CE; Mon, 25 Aug 2014 17:14:01 -0500 (CDT) Message-ID: <53FBB527.9030007@agliodbs.com> Date: Mon, 25 Aug 2014 15:13:59 -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: Andres Freund CC: Bruce Momjian , pgsql-performance@postgresql.org, 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> <53F4F36E.6050003@agliodbs.com> <20140821024036.GB26706@momjian.us> <53F65E62.3020909@agliodbs.com> <20140822140223.GP17406@alap3.anarazel.de> 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 On 08/22/2014 07:02 AM, Andres Freund wrote: > 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. The only cases I've seen where HT can be beneficial is when you have large numbers of idle connections. Then the idle connections can be "parked" on the HT virtual cores. However, even in this case I haven't seen a head-to-head performance comparison. -- 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