linux-kernel - Re: [PATCHSET 00/12] perf tools: Apply percent-limit to callchains

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Date:	Tue, 26 Jan 2016 14:27:26 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Namhyung Kim <namhyung@...nel.org>
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>,
	Andi Kleen <andi@...stfloor.org>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCHSET 00/12] perf tools: Apply percent-limit to callchains

On Tue, Jan 26, 2016 at 09:51:59PM +0900, Namhyung Kim wrote:
> On Tue, Jan 26, 2016 at 01:14:47PM +0100, Jiri Olsa wrote:
> > On Sun, Jan 24, 2016 at 10:53:23PM +0900, Namhyung Kim wrote:
> > > Hello,
> > > 
> > > This patchset tries to implement percent limit to callchains which was
> > > requested by Andi Kleen.  For some reason, limiting callchains by
> > > (overhead) percentage didn't work well.  This patch fixes it and make
> > > --percent-limit also works for callchains as well as hist entries.
> > > 
> > > This is available on 'perf/callchain-limit-v1' branch in my tree:
> > > 
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
> > > 
> > > Any comments are welcome,
> > > 
> > > Thanks,
> > > Namhyung
> > > 
> > > 
> > > Namhyung Kim (12):
> > >   perf report: Apply --percent-limit to callchains also
> > >   perf report: Apply callchain percent limit on --stdio
> > >   perf report: Get rid of hist_entry__callchain_fprintf()
> > >   perf report: Fix percent calculation on --stdio
> > >   perf report: Hide output pipe for percent-limited callchains on stdio
> > >   perf hists browser: Fix dump to show correct callchain style
> > >   perf hists browser: Fix callchain_node__count_rows()
> > >   perf hists browser: Apply callchain percent limit
> > >   perf hists browser: Fix callchain counting when press ENTER key
> > >   perf hists browser: Fix counting callchains when expand/collapse all
> > >   perf hists browser: Update percent base for fractal callchain mode
> > >   perf report: Fix callchain percent limit on --gtk
> > 
> > is 0.5 the default or one has to use the --percent-limit 0.5
> > for the limit to be effective?
> 
> Yes, it's effective now.  I also think we need to change the default
> limit of 0.5.  It was set for 'fractal' mode initially AFAIK so its
> percentage is relative to each node.  In this case 0.5% of limit makes
> sense because it'll be a very small (absolute) value.
> 
> But With 'graph' mode (now default), there're many entries under 0.5
> overhead and they silently won't show callchains anymore.  Actually I
> was confused by it when working with this patchset.
> 
> What about 0.005% for the new default?
> 
> 
> > 
> > without the option I'm getting empty callchains that are below 0.5
> > but only in TUI mode (attached).. --stdio shows them all unfolded
> 
> It should not show them all.  But I found that I missed a check for
> a stdio case.  Could you please test below?

did not help, it's still there.. same output as before

jirka