Re: [RFC PATCH 0/4] timers: framework for migration between CPU

From: Arjan van de Ven
Date: Fri Feb 20 2009 - 14:57:49 EST


On Fri, 20 Feb 2009 17:07:37 +0100
Ingo Molnar <mingo@xxxxxxx> wrote:

>
> * Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx> wrote:
>
> > > I'd also suggest to not do that rather ugly
> > > enable_timer_migration per-cpu variable, but simply reuse
> > > the existing nohz.load_balancer as a target CPU.
> >
> > This is a good idea to automatically bias the timers. But
> > this nohz.load_balancer is a very fast moving target and we
> > will need some heuristics to estimate overall system idleness
> > before moving the timers.
> >
> > I would agree that the power saving load balancer has a good
> > view of the system and can potentially guide the timer biasing
> > framework.
>
> Yeah, it's a fast moving target, but it already concentrates
> the load somewhat.
>

I wonder if the real answer for this isn't to have timers be considered
schedulable-entities and have the regular scheduler decide where they
actually run.

--
Arjan van de Ven Intel Open Source Technology Centre
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visit http://www.lesswatts.org
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