linux-kernel - Re: [PATCH v2 1/3] process cputimer is moving faster than its corresponding clock

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Message-ID: <1367256561.8833.9.camel@Wailaba2>
Date:	Mon, 29 Apr 2013 13:29:21 -0400
From:	Olivier Langlois <olivier@...llion01.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>, schwidefsky@...ibm.com,
	Steven Rostedt <rostedt@...dmis.org>,
	KOSAKI Motohiro <kosaki.motohiro@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/3] process cputimer is moving faster than its
 corresponding clock

On Mon, 2013-04-29 at 02:45 +0200, Frederic Weisbecker wrote:
> 2013/4/27 Olivier Langlois <olivier@...llion01.com>:
> >
> >
> > Forbids the cputimer to drift ahead of its process clock by
> > blocking its update when a tick occurs while a autoreaping task
> > is currently in do_exit() between the call to release_task() and
> > its final call to schedule().
> >
> > Any task stats update after having called release_task() will
> > be lost because they are added to the global process stats located
> > in the signal struct from release_task().
> >
> > Ideally, you should postpone the release_task() call after the
> > final context switch to get all the stats added but this is
> > more complex to achieve.
> >
> > In other words, this is slowing down the cputimer so it keep the same
> > pace than the process clock but in fact, what should be done is to
> > speed up the process clock by adding the missing stats to it.
> >
> > Signed-off-by: Olivier Langlois <olivier@...llion01.com>
> 
> Thanks.
> 
> Could you please resend these three patches in a new mail thread to
> make reviews easier? Also it would be nice to propose a different
> subject for each individual patch. Each of which describing what the
> patch does in a few words.
> 
> Thanks.

Frederic, Ok. I will do it and keep the description brief. If someone
inquire more details, I will make them refer back to specific post
inside this thread to avoid unnecessary repetition.

Is this cool?




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