linux-kernel - Re: [PATCH v2 2/3] perf script: Print comm, fork and exit events also

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Message-ID: <20131125134259.GB20168@ghostprotocols.net>
Date:	Mon, 25 Nov 2013 10:42:59 -0300
From:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
To:	Namhyung Kim <namhyung@...nel.org>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung.kim@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>, David Ahern <dsahern@...il.com>
Subject: Re: [PATCH v2 2/3] perf script: Print comm, fork and exit events also

Em Tue, Nov 19, 2013 at 09:18:20AM +0900, Namhyung Kim escreveu:
> On Mon, 18 Nov 2013 10:57:00 -0300, Arnaldo Carvalho de Melo wrote:
> > Em Mon, Nov 18, 2013 at 02:34:53PM +0900, Namhyung Kim escreveu:
> >> If --show-task option is given, also print internal COMM, FORK and
> >> EXIT events.  It would be helpful for debugging.

> > Humm, --show-task-events is clearer albeit long :-\ With shell
> > completion shouldn't be an issue tho.
 
> Okay, will change.

Ok, waiting for a new patchset then.
 
> > Also, can't we use: perf_event__fprintf_{mmap,comm,task}?
 
> We can do it.  The output will look like below if we use
> perf_event__fprintf():
 
>           swapper     0 [009] 3350640.335261: sched:sched_switch: prev_comm=swapper/9
>             sleep  9486 [009] 3350640.335509: PERF_RECORD_COMM: sleep:9486
>             sleep  9486 [009] 3350640.335806: sched:sched_stat_runtime: comm=sleep pid=9486
>           firefox  2635 [003] 3350641.275896: PERF_RECORD_FORK(2635:9487):(2635:2635)
>           firefox  2635 [003] 3350641.275896: sched:sched_process_fork: comm=firefox pid=2635
>             sleep  9486 [009] 3350641.336009: PERF_RECORD_EXIT(9486:9486):(9486:9486)

> But I'd prefer original version below since it shows the changes more
> intuitively, no?

Well, by reusing perf_event__fprintf() we will make it clear the kind of
that event, i.e. its not a tracepoint, but a sideband record generated
by the perf infrastructure.

Or perhaps we can change perf_event__fprintf* to show:

           swapper     0 [009] 3350640.335261: sched:sched_switch: prev_comm=swapper/9
             sleep  9486 [009] 3350640.335509: perf:comm: sleep:9486
             sleep  9486 [009] 3350640.335806: sched:sched_stat_runtime: comm=sleep pid=9486
           firefox  2635 [003] 3350641.275896: perf:fork(2635:9487):(2635:2635)
           firefox  2635 [003] 3350641.275896: sched:sched_process_fork: comm=firefox pid=2635
             sleep  9486 [009] 3350641.336009: perf:exit(9486:9486):(9486:9486)

Would that look nicer here and in 'perf report -D'? Ingo?

- Arnaldo
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