From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754684AbcEDRrL (ORCPT ); Wed, 4 May 2016 13:47:11 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:39242 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753385AbcEDRrJ (ORCPT ); Wed, 4 May 2016 13:47:09 -0400 Date: Wed, 4 May 2016 13:46:16 -0400 From: Chris Mason To: Peter Zijlstra CC: Mike Galbraith , Ingo Molnar , Matt Fleming , Subject: Re: sched: tweak select_idle_sibling to look for idle threads Message-ID: <20160504174616.k4xud2w232b6m4by@floor.masoncoding.com> Mail-Followup-To: Chris Mason , Peter Zijlstra , Mike Galbraith , Ingo Molnar , Matt Fleming , linux-kernel@vger.kernel.org References: <20160409190554.honue3gtian2p6vr@floor.thefacebook.com> <20160430124731.GE2975@worktop.cust.blueprintrf.com> <1462086753.9717.29.camel@suse.de> <20160502084615.GB3430@twins.programming.kicks-ass.net> <1462200604.3736.42.camel@suse.de> <20160502145817.GW3408@twins.programming.kicks-ass.net> <20160502154725.ckiewczbdubudyc7@floor.masoncoding.com> <20160503143225.GG3448@twins.programming.kicks-ass.net> <20160503151153.wp6jcnjadmw2ypmx@floor.masoncoding.com> <20160504154510.GH3448@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20160504154510.GH3448@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.23.1 (2014-03-12) X-Originating-IP: [192.168.52.123] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-05-04_07:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 04, 2016 at 05:45:10PM +0200, Peter Zijlstra wrote: > On Tue, May 03, 2016 at 11:11:53AM -0400, Chris Mason wrote: > > # pick a single core, in my case cpus 0,20 are the same core > > # cpu_hog is any program that spins > > # > > taskset -c 20 cpu_hog & > > > > # schbench -p 4 means message passing mode with 4 byte messages (like > > # pipe test), no sleeps, just bouncing as fast as it can. > > # > > # make the scheduler choose between the sibling of the hog and cpu 1 > > # > > taskset -c 0,1 schbench -p 4 -m 1 -t 1 > > Will that schbench thingy print something? Mine doesn't seem to output > anything, not actually exit, although it stops consuming CPU cycles at > some point. > > It should, make sure you're at the top commit in git. git://git.kernel.org/pub/scm/linux/kernel/git/mason/schbench.git It's not recent so I'd be surprised if you weren't already there. The default runtime is 30 seconds, but you can use -r to specify something shorter. It's possible I'm missing a wakeup to shut the whole thing down, but I thought I fixed that. ./schbench -p 4 -m 1 -t 1 Latency percentiles (usec) 50.0000th: 5 75.0000th: 5 90.0000th: 5 95.0000th: 5 *99.0000th: 8 99.5000th: 15 99.9000th: 17 Over=0, min=0, max=652 avg worker transfer: 113768.27 ops/sec 444.41KB/s -chris