Re: [PATCH 1/2] sched/fair: move cpufreq hook to update_cfs_rq_load_avg()

From: Peter Zijlstra
Date: Fri Apr 01 2016 - 05:20:31 EST


On Thu, Mar 31, 2016 at 02:26:06PM -0700, Steve Muckle wrote:
> > Can't, the way the wakeup path is constructed we would be sending the
> > IPI way before we know about utilization.
>
> Sorry I thought we were referring to the possibility of sending an IPI
> to just run the cpufreq driver rather than to conduct the whole wakeup
> operation.
>
> My thinking was in CFS we get rid of the (cpu == smp_processor_id())
> condition for calling the cpufreq hook.
>
> The sched governor can then calculate utilization and frequency required
> for cpu. If (cpu == smp_processor_id()), the update is processed
> normally. If (cpu != smp_processor_id()) and the new frequency is higher
> than cpu's Fcur, the sched gov IPIs cpu to continue running the update
> operation. Otherwise, the update is dropped.
>
> Does that sound plausible?

Can be done I suppose..