linux-kernel - Re: [PATCHSET 00/10] perf tools: Apply percent-limit to callchains (v2)

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Date:	Thu, 28 Jan 2016 19:14:14 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Jiri Olsa <jolsa@...hat.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>,
	Andi Kleen <andi@...stfloor.org>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCHSET 00/10] perf tools: Apply percent-limit to callchains (v2)

On Thu, Jan 28, 2016 at 5:16 PM, Jiri Olsa <jolsa@...hat.com> wrote:
> On Thu, Jan 28, 2016 at 12:40:47AM +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.
>>
>>  * Changes from v1)
>>   - fix insertion path instead of changing all UI code
>>   - show percent value even on single path (if needed)
>>   - change default callchain percent limit
>>
>> This is available on 'perf/callchain-limit-v2' branch in my tree:
>>
>>   git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
>>
>> Any comments are welcome,
>>
>> Thanks,
>> Namhyung
>> *** BLURB HERE ***
>>
>> Namhyung Kim (10):
>>   perf hists: Fix min callchain hits calculation
>>   perf hists: Update hists' total period when adding entries
>>   perf report: Apply --percent-limit to callchains also
>>   perf report: Get rid of hist_entry__callchain_fprintf()
>>   perf tools: Pass parent_samples to __callchain__fprintf_graph()
>>   perf report: Fix percent display in callchains on --stdio
>>   perf hists browser: Fix dump to show correct callchain style
>>   perf hists browser: Pass parent_total to callchain print functions
>>   perf hists browser: Fix percent display in callchains
>>   perf tools: Change default calchain percent limit to 0.005%
>
> also I see extra fo entries with callchain filtered out in stdio mode
>
> jirka
>
>
> ---
>      8.41%  yes      libc-2.21.so      [.] fputs_unlocked
>             |
>             ---fputs_unlocked
>                |
>                |--5.67%--0x757074756f206472
>                |
>                 --2.74%--0x3ba8e0
>                           0x21e000
>
>      2.47%  yes      yes               [.] fputs_unlocked@plt
>             |
>             ---fputs_unlocked@plt
>                0x3ba8e0
>                0x21e000
>
>      0.12%  yes      [kernel.vmlinux]  [k] vfs_write
>
>      0.09%  yes      libc-2.21.so      [.] _IO_do_write@@GLIBC_2.2.5
>
>      0.08%  yes      [kernel.vmlinux]  [k] entry_SYSCALL_64
>
>      0.07%  yes      [kernel.vmlinux]  [k] fsnotify
>
>      0.06%  yes      [kernel.vmlinux]  [k] sys_write
>

I guess it's same for other UI outputs too.

The default limit of hist entries is 0 so it basically shows all
entries.  But default callchain limit is 0.5% so hist entries under
0.5% won't show callchains.

Thanks,
Namhyung