From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753242AbaIKVae (ORCPT ); Thu, 11 Sep 2014 17:30:34 -0400 Received: from mail.kernel.org ([198.145.19.201]:39287 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753123AbaIKVac (ORCPT ); Thu, 11 Sep 2014 17:30:32 -0400 Date: Thu, 11 Sep 2014 18:30:27 -0300 From: Arnaldo Carvalho de Melo To: Mike Galbraith Cc: Namhyung Kim , LKML Subject: Re: perf top -g -U --sort=symbol --children == lalalalala? Message-ID: <20140911213027.GB1801@kernel.org> References: <1410263641.15383.8.camel@marge.simpson.net> <20140909133737.GK2773@kernel.org> <1410439392.20184.17.camel@marge.simpson.net> <20140911134338.GE10158@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140911134338.GE10158@kernel.org> 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 Em Thu, Sep 11, 2014 at 10:43:38AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Sep 11, 2014 at 02:43:12PM +0200, Mike Galbraith escreveu: > > On Thu, 2014-09-11 at 17:09 +0900, Namhyung Kim wrote: > > > On Tue, Sep 9, 2014 at 10:37 PM, Arnaldo Carvalho de Melo > > > wrote: > > > > Em Tue, Sep 09, 2014 at 01:54:01PM +0200, Mike Galbraith escreveu: > > > >> Seems the now default on --children thingy doesn't like -U much. > > > > Namhyung, can you please take a look at this? > > > So what is the problem here? > > Well, if you don't see anything wrong, I guess nothing at all. > :-) > I think that when we decide that it is so better to change defaults like > we did this time, we should be required to add a big fat warning (a > --tui popup, use the first lines on --stdio, etc) about why the default > was changed and allow quick, easy opt out, restoring previous behaviour > after the user, being warned, knows what to expect, tries it, and then > is in a better position to decide if keeping the new default is what is > desired. Also, looking at the changelog entries and at tools/perf/Documentation/ the only description for --children, the default, is: ---------------- --children:: Accumulate callchain of children to parent entry so that then can show up in the output. The output will have a new "Children" column and will be sorted on the data. It requires callchains are recorded. ---------------- I think that a longer/clearer entry in the 'perf record' man page is required. Perhaps the description got lost in a --cover-letter for the patch series implementing it? - Arnaldo > > > > >> Samples: 5K of event 'cycles', Event count (approx.): 2268660922 > > > >> Children Self Symbol > > > >> + 46.42% 0.04% [k] system_call_fastpath > > > I'll just turn it off until I figure out what cool stuff this is telling > > me. why that symbol becomes the number one hit, and why total% > 100. > > > To me, it looks like top smoked it's breakfast, went to lala land ;-) > > Yeah, its confusing, I'll let Namhyung explain it ;-) > > :-) > > - Arnaldo