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From: Dario Faggioli <raistlin@linux.it>
To: Colin Cross <ccross@android.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Hillf Danton <dhillf@gmail.com>
Subject: Re: [PATCH] sched/rt: fix SCHED_RR across cgroups
Date: Wed, 23 May 2012 15:32:24 +0200	[thread overview]
Message-ID: <1337779944.27368.94.camel@Solace> (raw)
In-Reply-To: <CAMbhsRQYgOQA7NB-mdMDi8GxtTaZDQhED2J2X9YmyiYjAzXx4w@mail.gmail.com>

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On Sat, 2012-05-19 at 13:37 -0700, Colin Cross wrote:
> > I would say it is. That's what you get because of putting task1 and
> > cgroup at the same level in the "hierarchy". I'm curious, what kind of
> > behaviour were you expecting?
> 
> That behavior matches exactly with scheduling of normal tasks and
> cgroups with default cpu.shares, but doesn't match too well with what
> I can see of the posix SCHED_RR description, which suggests all the
> SCHED_RR threads go into a single queue.  I was just curious if the
> behavior my patch restored was correct, since it can't be adjusted by
> tweaking any parameters like cpu.shares.
> 
Again, I really think it is the intended behaviour, and yes, real-time
group scheduling "breaks" the POSIX specification of the SCHED_{FIFO,RR}
policies intentionally (and _proudly_, as Peter would say it, am I
wrong? :-P).

Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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  reply	other threads:[~2012-05-23 13:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-17  4:34 [PATCH] sched/rt: fix SCHED_RR across cgroups Colin Cross
2012-05-18  8:56 ` Peter Zijlstra
2012-05-18 17:52   ` Colin Cross
2012-05-18 18:37     ` Peter Zijlstra
2012-05-19  0:13       ` Colin Cross
2012-05-19 13:11         ` Dario Faggioli
2012-05-19 20:37           ` Colin Cross
2012-05-23 13:32             ` Dario Faggioli [this message]
2012-05-25 11:52               ` Peter Zijlstra
2012-05-25 13:12                 ` Steven Rostedt
2012-05-25 17:55                   ` Paul E. McKenney
2012-05-30 13:40 ` [tip:sched/urgent] sched/rt: Fix " tip-bot for Colin Cross

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