From: Milian Wolff <milian.wolff@kdab.com>
To: yuzhoujian <ufo19890607@gmail.com>
Cc: peterz@infradead.org, mingo@redhat.com,
        alexander.shishkin@linux.intel.com, jolsa@kernel.org,
        dsahern@gmail.com, namhyung@kernel.org, yuzhoujian@didichuxing.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] perf script: Add script per-event-dump support
Date: Wed, 13 Sep 2017 20:51:10 +0200
Message-ID: <1613196.WrfoOBG8ky@agathebauer>
Organization: KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
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On Mittwoch, 13. September 2017 17:10:30 CEST yuzhoujian wrote:
> Introduce a new option to print trace output to files named by the
> monitored events and update perf-script documentation accordingly.
> 
> Shown below is output of perf script command with the newly introduced
> option.
> 
>         $perf record -e cycles -e context-switches -ag -- sleep 10
>         $perf script --per-event-dump
>         $ls /
>         cycles.stacks context-switches.stacks
> 
> Without per-event-dump support, drawing flamegraphs for different events
> is really hard. You can only monitor one event at a time for perf record.
> Using this option, we can get the trace output files named by the monitored
> events, and could draw flamegraphs according to the event's name.

Not going to argue for or against this patch, but I think the reasoning you 
give in your commit message is outdated:

https://github.com/brendangregg/FlameGraph/commit/
4b7b3169ed303d33fb710e1b9de235b84cc119d3

I.e. with a recent FlameGraph, you can generate flame graphs for different 
events just fine, without any intermediate step.

Cheers

-- 
Milian Wolff | milian.wolff@kdab.com | Senior Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts