Re: [RFC][PATCH 3/7] sched: power: go_faster/slower power driverhints

[Morten Rasmussen]

On Mon, Oct 14, 2013 at 02:48:09PM +0100, Peter Zijlstra wrote:
> On Fri, Oct 11, 2013 at 06:19:13PM +0100, Morten Rasmussen wrote:
> > +static inline void inc_cpu_capacity(int cpu)
> > +{
> > +	if (weighted_cpuload(cpu) > power_of(cpu))
> > +		go_faster(cpu, 0);
> > +}
> > +
> > +static inline void dec_cpu_capacity(int cpu)
> > +{
> > +	if (weighted_cpuload(cpu) < power_of(cpu))
> > +		go_slower(cpu, 0);
> > +}
> 
> It seems wrong to me to use weighted_cpuload() here; that contains the
> task weight, which is irrelevant to power usage. I would expect a pure
> utilization term here.
> 
> Something like:
> 
>   se->avg.runnable_avg_sum / se->avg.runnable_avg_period
> 

Fully agree. There is no unweighted equivalent to cfs.runnable_load_avg
but we could add it. It would be very useful for the power-aware
scheduling. It will add some overhead though.

Morten

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