Received: from magus.postgresql.org ([87.238.57.229]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TDsTi-0001ag-W8 for pgsql-performance@postgresql.org; Tue, 18 Sep 2012 07:44:19 +0000 Received: from host36.ns3.it ([80.79.54.36] helo=mail.opinioni.net) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TDsTf-0002la-Tt for pgsql-performance@postgresql.org; Tue, 18 Sep 2012 07:44:18 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.opinioni.net (Postfix) with ESMTP id 0C1DF468D52 for ; Tue, 18 Sep 2012 09:51:02 +0200 (CEST) Received: from mail.opinioni.net ([127.0.0.1]) by localhost (opinioni.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SC-umyFH0noJ for ; Tue, 18 Sep 2012 09:51:01 +0200 (CEST) Received: from [192.168.1.50] (78-134-6-72.v4.ngi.it [78.134.6.72]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.opinioni.net (Postfix) with ESMTPS id CF8B6468D51 for ; Tue, 18 Sep 2012 09:51:01 +0200 (CEST) Message-ID: <5058264D.5090702@opinioni.net> Date: Tue, 18 Sep 2012 09:44:13 +0200 From: Andrea Suisani User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120827 Thunderbird/15.0 MIME-Version: 1.0 To: pgsql-performance@postgresql.org Subject: Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201209/84 X-Sequence-Number: 47830 On 09/14/2012 10:45 AM, Daniel Farina wrote: > On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky wrote: >> Hi >> I compiled the 3.6-rc5 kernel with the same config from 3.5.3 and got >> the 15-20% performance drop of PostgreSQL 9.2 on AMD chipsets (880G, >> 990X). [cut] >> Kernel config - http://pastebin.com/cFpg5JSJ >> >> Any ideas? > > Did you tell LKML? It seems like a kind of change that could be found > using git bisect of Linux, albiet laboriously. just a pointer to LKML thread: https://lkml.org/lkml/2012/9/14/99 it seems that kernel dev were able to find the root cause after bisecting kernel source. Borislav Petkov says that regression disappears after reverting this commit: commit 970e178985cadbca660feb02f4d2ee3a09f7fdda Author: Mike Galbraith Date: Tue Jun 12 05:18:32 2012 +0200 Andrea