linux-kernel - Re: [PATCH 13/16] perf callchain: Switch default to 'graph,0.5,caller'

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Message-ID: <20151021132122.GD10639@kernel.org>
Date:	Wed, 21 Oct 2015 10:21:22 -0300
From:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Brendan Gregg <brendan.d.gregg@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Borislav Petkov <bp@...e.de>,
	Chandler Carruth <chandlerc@...il.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Stephane Eranian <eranian@...gle.com>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH 13/16] perf callchain: Switch default to
 'graph,0.5,caller'

Em Wed, Oct 21, 2015 at 10:06:45AM +0200, Ingo Molnar escreveu:
> * Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> wrote:
> > Indeed, finding a default that is deemed adequate for most people is, ho-hum, 
> > difficult 8-)

> > Ingo, what do you think?
 
> So I think the new default is a lot more intuitive, because it starts with a high 
> level top-down 'overview' kind of output, allowing one to drill down to the 
> details.
 
> That's what most other tools do as well by default, and people migrating to perf 
> found it pretty confusing that we do a bottom-up kind of callgraph.
 
> To people using perf for the first time it does not matter nearly as much, but 
> intuitiveness is still a factor.
 
> The new default requires good call-chains and good symbol resolution to be 
> maximally effective, but we want perfect callchains and symbols in any case, 
> right?

Sure, but in hindsight, we could've fixed those problems before flipping
the switch :-)

And also we didn't care about it that much because for callee based
callchains they are far from the focus point.

- Arnaldo
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