From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758276AbcFAIkq (ORCPT ); Wed, 1 Jun 2016 04:40:46 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43257 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757505AbcFAIkn (ORCPT ); Wed, 1 Jun 2016 04:40:43 -0400 Date: Wed, 1 Jun 2016 10:40:35 +0200 From: Peter Zijlstra To: "Huang, Ying" Cc: Ingo Molnar , lkp@01.org, Mike Galbraith , linux-kernel@vger.kernel.org, Thomas Gleixner , Linus Torvalds Subject: Re: [LKP] [lkp] [sched/fair] 53d3bc773e: hackbench.throughput -32.9% regression Message-ID: <20160601084035.GL3190@twins.programming.kicks-ass.net> References: <87inxud4ex.fsf@yhuang-dev.intel.com> <87eg8id3s3.fsf@yhuang-dev.intel.com> <20160531124151.GK3190@twins.programming.kicks-ass.net> <87eg8h8pwl.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87eg8h8pwl.fsf@yhuang-dev.intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 01, 2016 at 01:00:10PM +0800, Huang, Ying wrote: > Hi, Peter, > > Peter Zijlstra writes: > > > On Tue, May 31, 2016 at 04:34:36PM +0800, Huang, Ying wrote: > >> Hi, Ingo, > >> > >> Part of the regression has been recovered in v4.7-rc1 from -32.9% to > >> -9.8%. But there is still some regression. Is it possible for fully > >> restore it? > > > > after much searching on how you guys run hackbench... I figured > > something like: > > > > perf bench sched messaging -g 20 --thread -l 60000 > > There is a reproduce file attached in the original report email, its > contents is something like below: > > 2016-05-15 08:57:02 echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > 2016-05-15 09:06:24 /usr/bin/hackbench -g 24 --threads -l 60000 > > Hope that will help you for reproduce. It did not, because I didn't have the exact same machine and its not apparent how I should modify -- if at all -- the arguments to be representative when ran on my machine. > > on my IVB-EP (2*10*2) is similar to your IVT thing. > > > > And running something like: > > > > for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i ; done > > perf stat --null --repeat 10 -- perf bench sched messaging -g 20 --thread -l 60000 | grep "seconds time elapsed" > > > > gets me: > > > > v4.6: > > > > 36.786914089 seconds time elapsed ( +- 0.49% ) > > 37.054017355 seconds time elapsed ( +- 1.05% ) > > > > > > origin/master (v4.7-rc1-ish): > > > > 34.757435264 seconds time elapsed ( +- 3.34% ) > > 35.396252515 seconds time elapsed ( +- 3.38% ) > > > > > > Which doesn't show a regression between v4.6 and HEAD; in fact it shows > > an improvement. > > Yes. For hackbench test, linus/master (v4.7-rc1+) is better than v4.6, > but it is worse than v4.6-rc7. Details is as below. That kernel was broken.. what your point?