From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752933Ab3K2B6y (ORCPT ); Thu, 28 Nov 2013 20:58:54 -0500 Received: from mail-pd0-f177.google.com ([209.85.192.177]:49649 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751749Ab3K2B6s (ORCPT ); Thu, 28 Nov 2013 20:58:48 -0500 Message-ID: <5297F4D6.3070408@gmail.com> Date: Thu, 28 Nov 2013 18:58:46 -0700 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: Namhyung Kim CC: Arnaldo Melo , "linux-kernel@vger.kernel.org" , Ingo Molnar , Frederic Weisbecker , Peter Zijlstra , Mike Galbraith , Jiri Olsa , Stephane Eranian , Pekka Enberg Subject: Re: [PATCH 6/8] perf sched: Introduce timehist command References: <1384806771-2945-1-git-send-email-dsahern@gmail.com> <1384806771-2945-7-git-send-email-dsahern@gmail.com> <529768D3.1000507@gmail.com> <87k3fsowwe.fsf@sejong.aot.lge.com> In-Reply-To: <87k3fsowwe.fsf@sejong.aot.lge.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/28/13, 5:48 PM, Namhyung Kim wrote: > Do we really need to look up the callchain to find out an idle thread? > > $ perf sched script | grep swapper | head > swapper 0 [001] 4294177.326996: sched:sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Xorg next_pid=1094 next_prio=120 > swapper 0 [010] 4294177.327019: sched:sched_switch: prev_comm=swapper/10 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=13902 next_prio=120 > perf 13901 [002] 4294177.327074: sched:sched_switch: prev_comm=perf prev_pid=13901 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120 > swapper 0 [004] 4294177.327096: sched:sched_switch: prev_comm=swapper/4 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=synergys next_pid=1521 next_prio=120 > swapper 0 [000] 4294177.327102: sched:sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=gnome-terminal next_pid=2392 next_prio=120 > Xorg 1094 [001] 4294177.327112: sched:sched_switch: prev_comm=Xorg prev_pid=1094 prev_prio=120 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120 > swapper 0 [007] 4294177.327122: sched:sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=13902 next_prio=120 > migration/10 58 [010] 4294177.327124: sched:sched_switch: prev_comm=migration/10 prev_pid=58 prev_prio=0 prev_state=S ==> next_comm=swapper/10 next_pid=0 next_prio=120 > synergys 1521 [004] 4294177.327144: sched:sched_switch: prev_comm=synergys prev_pid=1521 prev_prio=120 prev_state=S ==> next_comm=swapper/4 next_pid=0 next_prio=120 > gnome-terminal 2392 [000] 4294177.327286: sched:sched_switch: prev_comm=gnome-terminal prev_pid=2392 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120 > > It seems every idle/swapper thread for each cpu has a pid of 0. The command was developed using context-switch events. Try the next patch and use: perf record -e cs -c 1 -ag perf sched timehist David