From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751851AbbIGMmk (ORCPT ); Mon, 7 Sep 2015 08:42:40 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:47910 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750848AbbIGMmj (ORCPT ); Mon, 7 Sep 2015 08:42:39 -0400 Date: Mon, 7 Sep 2015 14:42:20 +0200 From: Peter Zijlstra To: Morten Rasmussen Cc: mingo@redhat.com, vincent.guittot@linaro.org, daniel.lezcano@linaro.org, Dietmar Eggemann , yuyang.du@intel.com, mturquette@baylibre.com, rjw@rjwysocki.net, Juri Lelli , sgurrappadi@nvidia.com, pang.xunlei@zte.com.cn, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/6] sched/fair: Compute capacity invariant load/utilization tracking Message-ID: <20150907124220.GT18673@twins.programming.kicks-ass.net> References: <1439569394-11974-1-git-send-email-morten.rasmussen@arm.com> <20150831092449.GJ19282@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150831092449.GJ19282@twins.programming.kicks-ass.net> 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 Mon, Aug 31, 2015 at 11:24:49AM +0200, Peter Zijlstra wrote: > A quick run here gives: > > IVB-EP (2*20*2): As noted by someone; that should be 2*10*2, for a total of 40 cpus in this machine. > > perf stat --null --repeat 10 -- perf bench sched messaging -g 50 -l 5000 > > Before: After: > 5.484170711 ( +- 0.74% ) 5.590001145 ( +- 0.45% ) > > Which is an almost 2% slowdown :/ > > I've yet to look at what happens. OK, so it appears this is link order nonsense. When I compared profiles between the series, the one function that had significant change was skb_release_data(), which doesn't make much sense. If I do a 'make clean' in front of each build, I get a repeatable improvement with this patch set (although how much of that is due to the patches itself or just because of code movement is as yet undetermined). I'm of a mind to apply these patches; with two patches on top, which I'll post shortly.