From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752757AbbJTRVZ (ORCPT ); Tue, 20 Oct 2015 13:21:25 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:35500 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751793AbbJTRVT (ORCPT ); Tue, 20 Oct 2015 13:21:19 -0400 Date: Tue, 20 Oct 2015 19:21:16 +0200 From: Frederic Weisbecker To: Arnaldo Carvalho de Melo Cc: Chandler Carruth , Brendan Gregg , Ingo Molnar , LKML , Adrian Hunter , Borislav Petkov , David Ahern , Jiri Olsa , Namhyung Kim , Stephane Eranian , Wang Nan Subject: Re: [PATCH 13/16] perf callchain: Switch default to 'graph,0.5,caller' Message-ID: <20151020172114.GB29289@lerouge> References: <1444079018-31421-1-git-send-email-acme@kernel.org> <1444079018-31421-14-git-send-email-acme@kernel.org> <20151009215626.GM14409@kernel.org> <20151009222504.GN14409@kernel.org> <20151020120033.GB5119@kernel.org> <20151020121948.GA29289@lerouge> <20151020130651.GC5119@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151020130651.GC5119@kernel.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 20, 2015 at 10:06:51AM -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Oct 20, 2015 at 02:19:50PM +0200, Frederic Weisbecker escreveu: > > On Tue, Oct 20, 2015 at 09:00:34AM -0300, Arnaldo Carvalho de Melo wrote: > > > Em Mon, Oct 19, 2015 at 05:16:53PM -0700, Brendan Gregg escreveu: > > > So are you advocating different defaults, one for --stdio (callee), > > > another for --tui, --gtk (caller)? > > > > This is all configurable via ~/.perfconfig :-\ > > > > Indeed, finding a default that is deemed adequate for most people is, > > > ho-hum, difficult 8-) > > > Most uses I've seen on LKML by the past involved callee because people > > mostly look at the precise point where a performance issue is. > > A good chunk of that was because that was the default? I doubt it. When you need to find the culprit of a syscall of IRQ performance issue, you don't care much to see __libc_start_main() / main() on the top of your callchain. > > > IMHO changing that order is not a good idea. Unless many users complained > > about it. > > Perhaps there are not that many users of callchains because the default > is not what they're used to see? > > Motivation for the change came from a video from Chandler, that > resurfaced the callchain default issue, Chandler? > > Anedoctally, he tweeted about it and people seemed to like it. Well, I would prefer to hear from regular users than random twitter followers. I could be wrong so lets ask some users first. > > > Ingo, what do you think? > > What about providing a hotkey, in the tui, to toggle caller/callee > views, and another hotkey to save that in ~/.perfconfig so that becomes > the new default? That means rebuilding the whole tree, it might be costly and events need to be processed again. > > In the --stdio mode we need to add a warning in the first lines, > something like: > > # This is caller (or callee) based, please use --callchain ... to change it > > One way or the other people will disagree, so making it easy to switch > to the preferred way would be nice to have? Agreed. Thanks!