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

[Ingo Molnar <mingo@elte.hu>]

* Arjan van de Ven <arjan@infradead.org> wrote:

> On Fri, 20 Feb 2009 17:07:37 +0100
> Ingo Molnar <mingo@elte.hu> wrote:
> 
> > 
> > * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> 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.

hm, not sure - it's a bit heavy for that.

	Ingo