Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752903AbbKBXEp (ORCPT ); Mon, 2 Nov 2015 18:04:45 -0500 Received: from mail.kernel.org ([198.145.29.136]:38723 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751920AbbKBXEk (ORCPT ); Mon, 2 Nov 2015 18:04:40 -0500 Date: Mon, 2 Nov 2015 20:04:36 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Brendan Gregg , Ingo Molnar , Peter Zijlstra , Jiri Olsa , LKML , David Ahern , Frederic Weisbecker , Andi Kleen , Kan Liang Subject: Re: [RFC/PATCH 0/4] perf report: Support folded callchain output (v2) Message-ID: <20151102230436.GD21609@kernel.org> References: <1446469069-16223-1-git-send-email-namhyung@kernel.org> <20151102213021.GA21609@kernel.org> <20151102221204.GB10949@danjae.kornet> <20151102222842.GB21609@kernel.org> <20151102224927.GA11498@danjae.kornet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151102224927.GA11498@danjae.kornet> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6353 Lines: 146 Em Tue, Nov 03, 2015 at 07:49:27AM +0900, Namhyung Kim escreveu: > On Mon, Nov 02, 2015 at 07:28:42PM -0300, Arnaldo Carvalho de Melo wrote: > > Hi Namhyung, > > > > Em Tue, Nov 03, 2015 at 07:12:04AM +0900, Namhyung Kim escreveu: > > > On Mon, Nov 02, 2015 at 06:30:21PM -0300, Arnaldo Carvalho de Melo wrote: > > > > Em Mon, Nov 02, 2015 at 12:37:28PM -0800, Brendan Gregg escreveu: > > > > > On Mon, Nov 2, 2015 at 4:57 AM, Namhyung Kim wrote: > > > > > > This is what Brendan requested on the perf-users mailing list [1] to > > > > > > support FlameGraphs [2] more efficiently. This patchset adds a few > > > > > > more callchain options to adjust the output for it. > > > > > > > > At first, 'folded' output mode was added. The folded output puts all > > > > > > calchain nodes in a line separated by semicolons, a space and the > > > > > > value. Now it only supports --stdio as other UI provides some way of > > > > > > folding/expanding callchains dynamically. > > > > > > > > The value is now can be one of 'percent', 'period', or 'count'. The > > > > > > percent is current default output and the period is the raw number of > > > > > > sample periods. The count is the number of samples for each callchain. > > > > > > > > Here's an example: > > > > > > > > $ perf report --no-children --show-nr-samples --stdio -g folded,count > > > > > > ... > > > > > > 39.93% 80 swapper [kernel.vmlinux] [k] intel_idel > > > > > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary 57 > > > > > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;... 23 > > > > > > > So for the folded output I don't need the summary line (the row of > > > > > columns printed by hist_entry__snprintf()), and don't need anything > > > > > except folded stacks and the counts. If working with the existing > > > > > stdio interface is making it harder than it needs to be, might it be > > > > > > I don't think it so, just add some flag asking for that > > > > hist_entry__snprintf() to be supressed, ideas for a long option name? > > > > > > Having it as Namhyung did may have value for some people as a more > > > > compact way to show the callchains together with the hist_entry line. > > > > > Yeah, I'd keep the hist entry line unless it's too hard to > > > parse/filter. IMHO it's just a way to show callchains, so no need to > > > > What I suggested was to have something like: > > > > $ perf report --no-children --no-hists --stdio -g folded,count > > ^^^^^^^^^^ > > ^^^^^^^^^^ > > ... > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary 57 > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;... 23 > > > > I.e. the first entry in the callchain is 'intel_idle', just like in what > > Brendan called the 'summary line', i.e. reduntant when what he wants its > > just all the callchains and how many times they were sampled. > > Yep, I know. But isn't 'perf report' all for seeing hist lines? :) Well, so far, yes, but he is presenting a usecase where what we want to see is just callchains, and we can achieve that rather easily, no? > I'm not insisting it strongly, but it's a bit strange for me if perf > report doesn't show any hist lines.. If that is of no use in this use case, why not? > > > have separate output mode.. > > > > > Brendan, I guess you still need to know other info like cpu or pid, no? > > > > Possibly, but just with the callchains he has enough info for the basic > > flame graph, no? > > > > > And I feel like it'd be better to put the count before the callchains > > > for consistency like below. Is it OK to you? > > > > Consistency with what? > > Oh, I meant consistency with other callchain output style like graph, > fractal or flat - They all show the numbers before callchains. And I > think it's easier to read for human. :) Well, As I said, isn't the main object here the callchain? :-) And Brendan's request is for a something to be consumed by scripts, i.e. something like we have for perf stat: For humans: [root@felicio ~]# perf stat -e cycles -I 1000 -a # time counts unit events 1.000304391 1,820,038 cycles 2.000490191 1,005,477,007 cycles 3.000657813 1,717,007 cycles ^C 3.917890293 2,804,034 cycles For machines/scripts: [root@felicio ~]# perf stat -x, -e cycles -I 1000 -a 1.000291954,1923360,,cycles,3998167210,100.00 2.000477154,1005608105,,cycles,3998475482,100.00 3.000612612,1345483,,cycles,3998332391,100.00 4.000744469,1005046913,,cycles,3998258199,100.00 ^C 4.331684347,1551327,,cycles,3463190970,100.00 [root@felicio ~]# > > The main thing here is the callchain, all the other stuff are things > > related to it, so showing it first makes sense to me. > > > > Having some way to list the desired info to have for each callchain may > > be interesting, and if he could do it like: > > > > -g folded,count,cpu,other,fields > > > > then he would know how to parse the per-callchain info at the end of > > each line, right? > > Hmm.. looks like that it ends up having redundant info. I don't think What is redundant, and with with what? > it's generally useful to other 'perf report' stuffs. Wouldn't it be > better just adding minimal support and let the external tool parse the > output? Oh well, perhaps we could have a 'perf callchain' tool that would be centered on callchains and would provided one line per callchain, which would have: callchain;seprarated;colons series,of,desired,fields,for,this,callchain Which would reuse heavily the 'perf report' / 'perf top' code for histograms, no? I still think that this is a 'perf report' thing, but one that is centered in callchains, and that is to be consumed by scripts, not humans. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/