From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C0F4C04A6B for ; Wed, 8 May 2019 13:15:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1AFD1214AF for ; Wed, 8 May 2019 13:15:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557321330; bh=FcJSM/y2BlME+YwJKXMk2xvlnDqC5u1EXDgBURrRrFQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=De8KQMet+IE5P9/H9N6Q05IPS8nMSEwQ5hb9bO4zorQtO1XQ7p3U7vpJbZwS48Aoe XO9EBlqBl9adnU7dcZNJwBcX4Cg2ajNc8J400+riht5M3ti+OV0Q0hvAHhV2Z5Dh7z 2vDq/rsNa3Uky84EwzHs8mpB9yEhV50e4DkFAldI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727498AbfEHNP3 (ORCPT ); Wed, 8 May 2019 09:15:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:40282 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727453AbfEHNP3 (ORCPT ); Wed, 8 May 2019 09:15:29 -0400 Received: from tzanussi-mobl (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5685520850; Wed, 8 May 2019 13:15:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557321328; bh=FcJSM/y2BlME+YwJKXMk2xvlnDqC5u1EXDgBURrRrFQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Co24EdjTGma2lIPhu3U3ZulvyXwvV1sWJYNfPsrhv5STyAuxcjDRYveSac66hi0IN kIGk+y2Xs2qAZ5KZtn8Md1tUAGmo9OJ0d9/z4X8LxP5S3ib2KDyq7LB2QDBd1/QySn xsyIa8GbUlFGiwi7SvYCY0h8B6p1qENU/fejecGk= Message-ID: <1557321326.2167.5.camel@kernel.org> Subject: Re: [PATCH v2] Documentation/trace: Add clarification how histogram onmatch works From: Tom Zanussi To: Steven Rostedt , Tzvetomir Stoyanov Cc: linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Jonathan Corbet Date: Wed, 08 May 2019 08:15:26 -0500 In-Reply-To: <20190507201157.2673f2de@gandalf.local.home> References: <20190507144946.7998-1-tstoyanov@vmware.com> <20190507201157.2673f2de@gandalf.local.home> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.1-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Hi Steve, On Tue, 2019-05-07 at 20:11 -0400, Steven Rostedt wrote: > Tom, > > Can you review this patch. > Sure. > Jon, > > After Tom gives his review, can you take this in your tree? > > Thanks! > > Reviewed-by: Steven Rostedt (VMware) > Reviewed-by: Tom Zanussi Thanks, Tom > -- Steve > > > On Tue, 7 May 2019 17:49:46 +0300 > Tzvetomir Stoyanov wrote: > > > The current trace documentation, the section describing histogram's > > "onmatch" > > is not straightforward enough about how this action is applied. It > > is not > > clear what criteria are used to "match" both events. A short note > > is added, > > describing what exactly is compared in order to match the events. > > > > Signed-off-by: Tzvetomir Stoyanov > > --- > > Documentation/trace/histogram.txt | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/Documentation/trace/histogram.txt > > b/Documentation/trace/histogram.txt > > index 7ffea6aa22e3..d97f0530a731 100644 > > --- a/Documentation/trace/histogram.txt > > +++ b/Documentation/trace/histogram.txt > > @@ -1863,7 +1863,10 @@ hist trigger specification. > > > > The 'matching.event' specification is simply the fully > > qualified > > event name of the event that matches the target event for the > > - onmatch() functionality, in the form 'system.event_name'. > > + onmatch() functionality, in the form 'system.event_name'. > > Histogram > > + keys of both events are compared to find if events match. In > > the case > > + multiple histogram keys are used, both events must have the > > same > > + number of keys, and the keys must match in the same order. > > > > Finally, the number and type of variables/fields in the 'param > > list' must match the number and types of the fields in the > > @@ -1920,9 +1923,10 @@ hist trigger specification. > > /sys/kernel/debug/tracing/events/sched/sched_waking/tr > > igger > > > > Then, when the corresponding thread is actually scheduled onto > > the > > - CPU by a sched_switch event, calculate the latency and use > > that > > - along with another variable and an event field to generate a > > - wakeup_latency synthetic event: > > + CPU by a sched_switch event (where the sched_waking key > > "saved_pid" > > + matches the sched_switch key "next_pid"), calculate the > > latency and > > + use that along with another variable and an event field to > > generate > > + a wakeup_latency synthetic event: > > > > # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs- > > $ts0:\ > > onmatch(sched.sched_waking).wakeup_latency($wakeup_lat > > ,\ > >