linux-kernel - Re: [RFC/PATCHSET 00/17] perf tools: Add support for hierachy view (v2)

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Message-ID: <20160120150819.GB23604@danjae.kornet>
Date:	Thu, 21 Jan 2016 00:08:19 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Taeung Song <taeung.dev@...il.com>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Jiri Olsa <jolsa@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Stephane Eranian <eranian@...gle.com>,
	Andi Kleen <andi@...stfloor.org>,
	Wang Nan <wangnan0@...wei.com>,
	Don Zickus <dzickus@...hat.com>,
	Pekka Enberg <penberg@...nel.org>,
	Moinuddin Quadri <moin18@...il.com>
Subject: Re: [RFC/PATCHSET 00/17] perf tools: Add support for hierachy view
 (v2)

Hi Taeung,

On Wed, Jan 20, 2016 at 04:49:29PM +0900, Taeung Song wrote:
> 
> 
> On 01/20/2016 09:34 AM, Namhyung Kim wrote:
> >On Tue, Jan 19, 2016 at 05:59:41PM -0300, Arnaldo Carvalho de Melo wrote:
> >>Em Sun, Jan 17, 2016 at 01:03:00AM +0900, Namhyung Kim escreveu:
> >>>Hello,
> >>>
> >>>This is v2 attempt of my earlier patchset [1].  This patchset
> >>>implements a new feature that collects hist entries in a hierachical
> >>>manner.  That means lower-level entries belong to an upper-level
> >>>entry.  The entry hierachy is built on the sort keys given, so users
> >>>can set it whatever they want.  It only shows top-level entries first,
> >>>and user can expand/collapse it dynamically.
> >>>
> >>>This time I implemented it for every output browser including TUI.
> >>>A screenshot on TUI looks like below:
> >>>
> >>>For normal output:
> >>>
> >>>   $ perf report --tui
> >>>   Samples: 3K of event 'cycles:pp', Event count (approx.): 1695979674
> >>>     Overhead  Command        Shared Object         Symbol
> >>>   ------------------------------------------------------------------------
> >>>   -    7.57%  swapper        [kernel.vmlinux]      [k] intel_idle
> >>>        intel_idle
> >>>        cpuidle_enter_state
> >>>        cpuidle_enter
> >>>        call_cpuidle
> >>>      + cpu_startup_entry
> >>>   +    1.16   firefox        firefox               [.] 0x00000000000019433
> >>>   +    0.97%  firefox        libpthread-2.22.so    [.] pthread_mutex_lock
> >>>   ...
> >>>
> >>>
> >>>With hierarchy view,
> >>
> >>Ok, tested, this is really nice, I think it should be the default, from
> >>where to drill down, we could have a '--no-hierarchy', Ingo?
> >
> >Yeah, we already have --no-hierarchy (as a side effect of having
> >--hierarchy) but I don't want to change the default now since existing
> >users will complain.  Now we have 'tips' in the perf report browser,
> >maybe it's enough to add a line to suggest to use it (and it's already
> >done by this patchset).  I remember the time we changed default for
> >'--children' and many people complained about it.
> >
> >We maybe change the default later but I think it's better to have some
> >time to people can play with it and find it useful. :)  And, as always,
> >we can have a config option to control the default.
> 
> If adding this config option,
> can this be included in 'hist' section ?
> If it isn't, 'report' and 'top' section ?
> i.e.
> 
> [report]
>     hierarchy = true
> [top]
>     hierarchy = false

Either is fine.  But as we already have report.children and
top.children, I'd follow the convention.  Also I think we should set
priority of the two configs - children and hierarchy.  IMHO hierarchy
should be considered first.

Or maybe we could have 'report.output-default' being one of
'hierarchy', 'children', or 'normal'.  This way we can set the default
behavior easily including possible future changes.

Thanks,
Namhyung