From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935679AbYEVKek (ORCPT ); Thu, 22 May 2008 06:34:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753246AbYEVKea (ORCPT ); Thu, 22 May 2008 06:34:30 -0400 Received: from mail.gmx.net ([213.165.64.20]:42298 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750772AbYEVKe3 (ORCPT ); Thu, 22 May 2008 06:34:29 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1+PVb9l7nuPjaLCYYXH3ZIqYRCpkIpS/fLcSk/qlw 4jY7IoK2hmjWRG Subject: Re: PostgreSQL pgbench performance regression in 2.6.23+ From: Mike Galbraith To: Dhaval Giani Cc: Greg Smith , lkml , Peter Zijlstra , Ingo Molnar , Srivatsa Vaddagiri In-Reply-To: <1211447105.4823.7.camel@marge.simson.net> References: <1211440207.5733.8.camel@marge.simson.net> <20080522082814.GA4499@linux.vnet.ibm.com> <1211447105.4823.7.camel@marge.simson.net> Content-Type: text/plain Date: Thu, 22 May 2008 12:34:25 +0200 Message-Id: <1211452465.7606.8.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-05-22 at 11:05 +0200, Mike Galbraith wrote: > On Thu, 2008-05-22 at 13:58 +0530, Dhaval Giani wrote: > > Can you try with 2.6.26-rc? There is minimal load balancing for group > > scheduling till 25, which might explain the lack of scalability. > > I'm playing with it now, it's tweakable with migration cost. This > testcase is funky. It can't generate enough work to keep CPUs busy for > spit, and can't saturate my little quad with any kernel I've tried. Heh, watch this. No tweaking. (Nadia's ipc/idr patches are applied though, to see if the high end improves over previous runs with various kernels, and it does seem to.) 2.6.26-smp x86_64 1 10014.774797 2 9791.395302 3 10575.369296 4 9763.183251 5 10160.274262 6 9893.174179 8 9566.978464 10 10294.456456 15 9444.100540 20 9137.878618 30 8277.795499 40 7925.824428 50 7646.644285 nail postgres to CPUs1-3 nail pgbench to CPU0 2.6.26-smp x86_64 1 10900.959982 2 15976.870604 3 24661.322669 4 25347.141780 5 25893.815676 6 26756.414839 8 25399.018582 10 26172.878669 15 25542.082746 20 25090.381828 30 24270.301103 40 23405.867336 50 21926.223083