Re: [discussion]sched: a rough proposal to enable power saving inscheduler

[Matthew Garrett]

On Fri, Aug 17, 2012 at 11:44:03AM -0700, Arjan van de Ven wrote:
> On 8/17/2012 11:41 AM, Matthew Garrett wrote:
> > On Thu, Aug 16, 2012 at 07:01:25AM -0700, Arjan van de Ven wrote:
> >> this is ... a dubiously general statement.
> >>
> >> for good power, at least on Intel cpus, you want to spread. Parallelism is efficient.
> > 
> > Is this really true? In a two-socket system I'd have thought the benefit 
> > of keeping socket 1 in package C3 outweighed the cost of keeping socket 
> > 0 awake for slightly longer.
> 
> not on Intel
> 
> you can't enter package c3 either until every one is down.
> (e.g. memory controller must stay on etc etc)

I thought that was only PC6 - is there any reason why the package cache 
can't be entirely powered down?

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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