Re: [RFC PATCH 3/3] idle: store the idle state index in the struct rq

From: Nicolas Pitre
Date: Wed Feb 12 2014 - 14:05:35 EST


On Wed, 12 Feb 2014, Lorenzo Pieralisi wrote:

> On Wed, Feb 12, 2014 at 04:14:38PM +0000, Arjan van de Ven wrote:
> >
> > >> sched_cpu_cache_wiped(int llc)
> > >>
> > >> that would be very nice for this; the menuidle side knows this
> > >> for some cases and thus can just call it. This would be a very
> > >> small and minimal change
> > >
> > > What do you mean by "menuidle side knows this for some cases" ?
> > > You mean you know that some C-state entries imply llc clean/invalidate ?
> >
> > in the architectural idle code we can know if the llc got flushed
> > there's also the per core flags where we know with reasonable certainty
> > that the per core caches got flushed.
>
> Ok, but that's arch specific, not something we can detect from the menu
> governor in generic code , that's what I wanted to ask because it was not
> clear.

I would think this is meant to be called from architecture specific
backend code.


Nicolas
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