Subject: Re: [RFC PATCH 02/15] nohz_task: Avoid nohz task cpu as non-idle
 timer target
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
        Lai Jiangshan <laijs@cn.fujitsu.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Anton Blanchard <anton@au1.ibm.com>,
        Tim Pepper <lnxninja@linux.vnet.ibm.com>
In-Reply-To: <1292858662-5650-3-git-send-email-fweisbec@gmail.com>
References: <1292858662-5650-1-git-send-email-fweisbec@gmail.com>
	 <1292858662-5650-3-git-send-email-fweisbec@gmail.com>
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Date: Mon, 20 Dec 2010 16:47:58 +0100
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On Mon, 2010-12-20 at 16:24 +0100, Frederic Weisbecker wrote:
> Unbound timers are preferably targeted for non idle cpu. If
> possible though, prioritize idle cpus over nohz task cpus,
> because the main point of nohz task is to avoid unnecessary
> timer interrupts.

Oh is it?

I'd very much expect the cpu that arms the timer to get the interrupt. I
mean, if the task doesn't want to get interrupted by timers,
_DON'T_USE_TIMERS_ to begin with.

So no, don't much like this at all.
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