> On 4/5/2010 11:44,
david@lang.hm wrote:
> >On Mon, 5 Apr 2010, Arjan van de Ven wrote:
> >
> >>On 4/5/2010 8:14, Paul E. McKenney wrote:
> >>>So the main issue is that for many workloads, it is best to run full
> >>>bore
> >>>and get done quickly, thus allowing the entire machine to be powered
> >>>down?
> >>
> >>yep
> >
> >Race To Idle works extremely well in a batch type situation where there
> >is not going to be any work to do after you finish what you have.
> >
> >It doesn't work quite as well if you are going to have new work to do in
> >the near future.
> >
> >You cannot power down the entire machine if you have to look for user
> >input.
> >
> >It takes time (and power) to shut down and start back up, if you are
> >going to have more work to do before you can make the complete cycle
> >(and save more power than it costs to make the transitions), it's best
> >to stay at full power, even if you are idle.
>
> for the things we're talking about here (memory controllers etc) we're talking
> about single to low double digit microseconds (or even less) of time to go up and down.
> Many of the things you talk about are in the millisecond timeframe.
