Re: [RFC PATCH 02/15] nohz_task: Avoid nohz task cpu as non-idletimer target

From: Steven Rostedt
Date: Mon Dec 20 2010 - 11:06:51 EST


On Mon, 2010-12-20 at 16:47 +0100, Peter Zijlstra wrote:
> 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.

I think this comes from other tasks on other CPUs that are using timers.
Although, I'm not sure what causes an "unbound" timer to happen. I
thought timers usually go off on the CPU that asked for it to go off.

-- Steve


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