From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933904AbcHDOAu (ORCPT ); Thu, 4 Aug 2016 10:00:50 -0400 Received: from mga01.intel.com ([192.55.52.88]:29171 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933748AbcHDOAt (ORCPT ); Thu, 4 Aug 2016 10:00:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,470,1464678000"; d="scan'208";a="859690367" Date: Thu, 4 Aug 2016 21:57:59 +0800 From: Ye Xiaolong To: Peter Zijlstra Cc: Ingo Molnar , Vincent Guittot , Linus Torvalds , Mike Galbraith , Thomas Gleixner , LKML , lkp@01.org Subject: Re: [lkp] [sched/fair] e210bffd39: perf-stat.cpu-migrations -36.0% decrease Message-ID: <20160804135759.GA9114@yexl-desktop> References: <20160804052423.GA26201@yexl-desktop> <20160804090124.GK6879@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160804090124.GK6879@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/04, Peter Zijlstra wrote: >On Thu, Aug 04, 2016 at 01:24:23PM +0800, kernel test robot wrote: >> >> FYI, we noticed perf-stat.cpu-migrations -36.0% decrease due to commit: >> >> commit e210bffd39d01b649c94b820c28ff112673266dd ("sched/fair: Fix and optimize the fork() path") >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> >> in testcase: unixbench >> on test machine: 16 threads Broadwell-DE with 8G memory >> with following parameters: >> >> runtime: 300s >> nr_task: 1 >> test: shell8 >> cpufreq_governor: performance >> >> > >Urgh, I so hate these reports. They're near useless :/ > >It took me 3 readings to realize it was the unixbench testcase (why >isn't that in the subject!?). But then I still haven't found the primary Will add test name in subject in later performance reports. >performance metric. Does the test improve, degrade or not change >overall? > Sorry, I should have described it more clearly, the primary performance metric of unixbench is not changed, while perf-stat.cpu-migrations has a -36.0% decrease which should improve cache locality. We'd expect such stats changes report would help the developer to evaluate impacts of his patch, anyway, we'll make it more clear that it's just a FYI report, not some regression report. Thanks, Xiaolong >