From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751229Ab0DGCSr (ORCPT ); Tue, 6 Apr 2010 22:18:47 -0400 Received: from mga05.intel.com ([192.55.52.89]:32605 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751060Ab0DGCSm (ORCPT ); Tue, 6 Apr 2010 22:18:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.51,376,1267430400"; d="scan'208";a="555620447" Subject: Re: hackbench regression due to commit 9dfc6e68bfe6e From: "Zhang, Yanmin" To: Christoph Lameter Cc: Tejun Heo , Pekka Enberg , alex.shi@intel.com, "linux-kernel@vger.kernel.org" , "Ma, Ling" , "Chen, Tim C" , Andrew Morton In-Reply-To: References: <1269506457.4513.141.camel@alexs-hp.sh.intel.com> <1269570902.9614.92.camel@alexs-hp.sh.intel.com> <1270114166.2078.107.camel@ymzhang.sh.intel.com> <1270195589.2078.116.camel@ymzhang.sh.intel.com> <4BBA8DF9.8010409@kernel.org> <1270542497.2078.123.camel@ymzhang.sh.intel.com> Content-Type: text/plain; charset="ISO-8859-1" Date: Wed, 07 Apr 2010 10:20:40 +0800 Message-Id: <1270606840.2078.231.camel@ymzhang.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.0 (2.28.0-2.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-04-06 at 15:55 -0500, Christoph Lameter wrote: > We cannot reproduce the issue here. Our tests here (dual quad dell) show a > performance increase in hackbench instead. I run hackbench on many machines. The regression exists on Nehalem machine (dual sockets, 2*4*2 logical cpu) and a tigerton (4 socket, 4*4 logical cpu) machines. I tried it on a dual quad core2 machine and it does like what you said. The regression also exists on 2 new-generation Nehalem (dual socket 2*6*2 logical cpu) machines. It seems hyperthreading cpu has more chances to trigger it. > > Linux 2.6.33.2 #2 SMP Mon Apr 5 11:30:56 CDT 2010 x86_64 GNU/Linux > ./hackbench 100 process 200000 > Running with 100*40 (== 4000) tasks. > Time: 3102.142 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 308.731 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 311.591 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 310.200 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 38.048 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 44.711 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 39.407 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 9.411 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.765 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.822 > > Linux 2.6.34-rc3 #1 SMP Tue Apr 6 13:30:34 CDT 2010 x86_64 GNU/Linux > ./hackbench 100 process 200000 > Running with 100*40 (== 4000) tasks. > Time: 3003.578 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 300.289 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 301.462 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 301.173 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.191 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.964 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.470 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.829 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 9.166 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.681 > >