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From: Arun Sharma <asharma@fb.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	<linux-kernel@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Andrew Vagin <avagin@openvz.org>, Ingo Molnar <mingo@elte.hu>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] trace: reset sleep/block start time on task switch
Date: Fri, 10 Feb 2012 12:07:26 -0800	[thread overview]
Message-ID: <4F3578FE.7030904@fb.com> (raw)
In-Reply-To: <1328899383.25989.40.camel@laptop>

On 2/10/12 10:43 AM, Peter Zijlstra wrote:
> On Wed, 2012-01-25 at 11:50 -0800, Arun Sharma wrote:
>> # perf record -agP -e sched:sched_switch --filter "prev_state == 1 ||
>> prev_state == 2" -e  sched:sched_stat_sleep -- sleep 3
>
> Problem with that is it'll try and do a backtrace for all events, not
> only the sched_switch but also sched_stat_sleep, which is completely
> superfluous (and expensive).
>
> Currently perf tool doesn't support individual -g flags though and its
> slightly non-trivial to make it so. Easiest work-around would be two
> records and then merge the two files.

If we have a sequence of:

SL1, SW1, SL2, SW2, SL3, SW3

I think you're suggesting:

perf.data1: SL1, SL2, SL3 (without -g)
perf.data2: SW1, SW2, SW3 (with -g)

and then munge the data to create perf.data. But making sure that all 
matching sleep and switch events are captured seems hard.

  -Arun



      reply	other threads:[~2012-02-10 20:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-20  2:20 [PATCH] trace: reset sleep/block start time on task switch Arun Sharma
2012-01-23 11:34 ` Peter Zijlstra
2012-01-23 18:41   ` Arun Sharma
2012-01-23 21:03     ` Peter Zijlstra
2012-01-23 23:02       ` Arun Sharma
2012-01-24 14:27         ` Peter Zijlstra
2012-01-24 21:46           ` Arun Sharma
2012-01-25  9:20             ` Frederic Weisbecker
2012-01-25 19:50               ` Arun Sharma
2012-01-25 20:15                 ` Steven Rostedt
2012-01-25 22:29                   ` Arun Sharma
2012-01-26  2:27                     ` Frederic Weisbecker
2012-01-26 19:13                       ` Arun Sharma
2012-01-26  2:21                 ` Frederic Weisbecker
2012-02-10 18:43                 ` Peter Zijlstra
2012-02-10 20:07                   ` Arun Sharma [this message]

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