From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752482AbeDIJ4G (ORCPT ); Mon, 9 Apr 2018 05:56:06 -0400 Received: from mga03.intel.com ([134.134.136.65]:20397 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752061AbeDIJ4E (ORCPT ); Mon, 9 Apr 2018 05:56:04 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,426,1517904000"; d="scan'208";a="35631042" Subject: Re: [PATCH v5 1/3] perf/core: store context switch out type into Perf trace To: Peter Zijlstra Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , linux-kernel , linux-perf-users@vger.kernel.org References: <9ff84e83-a0ca-dd82-a6d0-cb951689be74@linux.intel.com> <20180409092603.GY4043@hirez.programming.kicks-ass.net> From: Alexey Budankov Organization: Intel Corp. Message-ID: <37886fed-e39f-3aa1-d909-0c91e746adc7@linux.intel.com> Date: Mon, 9 Apr 2018 12:56:00 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180409092603.GY4043@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09.04.2018 12:26, Peter Zijlstra wrote: > On Mon, Apr 09, 2018 at 10:25:32AM +0300, Alexey Budankov wrote: >> >> Store preempting context switch out event into Perf trace as a part of >> PERF_RECORD_SWITCH[_CPU_WIDE] record. >> >> Percentage of preempting and non-preempting context switches help >> understanding the nature of workloads (CPU or IO bound) that are running >> on a machine; >> >> The event is treated as preemption one when task->state value of the >> thread being switched out is TASK_RUNNING. Event type encoding is >> implemented using PERF_RECORD_MISC_SWITCH_OUT_PREEMPT bit; >> >> Signed-off-by: Alexey Budankov > > Acked-by: Peter Zijlstra (Intel) > > Acme, I'm thinking you should route this, since most of the changes are > actually to the tool. > >> diff --git a/kernel/events/core.c b/kernel/events/core.c >> index fc1c330c6bd6..872a5aaa77eb 100644 >> --- a/kernel/events/core.c >> +++ b/kernel/events/core.c >> @@ -7584,6 +7584,10 @@ static void perf_event_switch(struct task_struct *task, >> }, >> }; >> >> + if (!sched_in && task->state == TASK_RUNNING) >> + switch_event.event_id.header.misc |= >> + PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; > > I typically prefer {} over any multi-line expression. Yep, makes sense. Sorry for missing that here. > >> perf_iterate_sb(perf_event_switch_output, >> &switch_event, >> NULL); >