Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement

From: Peter Zijlstra
Date: Tue Mar 24 2015 - 09:01:19 EST


On Wed, Feb 04, 2015 at 06:31:10PM +0000, Morten Rasmussen wrote:
> @@ -5138,6 +5224,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
> prev_cpu = cpu;
>
> if (sd_flag & SD_BALANCE_WAKE) {
> + if (energy_aware()) {
> + new_cpu = energy_aware_wake_cpu(p);
> + goto unlock;
> + }
> new_cpu = select_idle_sibling(p, prev_cpu);
> goto unlock;
> }

So that is fundamentally wrong I think. We only care about power aware
scheduling when U < 1, after that we should do the normal thing. This
setup does not allow for that.
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