Re: [PATCH v6 09/16] sched/cpufreq: uclamp: Add utilization clamping for RT tasks

Patrick Bellasi
2019-01-22T12:37:04Z

On 22-Jan 12:30, Quentin Perret wrote:
> On Tuesday 15 Jan 2019 at 10:15:06 (+0000), Patrick Bellasi wrote:
> > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> > index 520ee2b785e7..38a05a4f78cc 100644
> > --- a/kernel/sched/cpufreq_schedutil.c
> > +++ b/kernel/sched/cpufreq_schedutil.c
> > @@ -201,9 +201,6 @@ unsigned long schedutil_freq_util(int cpu, unsigned long util_cfs,
> > unsigned long dl_util, util, irq;
> > struct rq *rq = cpu_rq(cpu);
> >
> > - if (type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt))
> > - return max;
> > -
> > /*
> > * Early check to see if IRQ/steal time saturates the CPU, can be
> > * because of inaccuracies in how we track these -- see
> > @@ -219,15 +216,19 @@ unsigned long schedutil_freq_util(int cpu, unsigned long util_cfs,
> > * utilization (PELT windows are synchronized) we can directly add them
> > * to obtain the CPU's actual utilization.
> > *
> > - * CFS utilization can be boosted or capped, depending on utilization
> > - * clamp constraints requested by currently RUNNABLE tasks.
> > + * CFS and RT utilization can be boosted or capped, depending on
> > + * utilization clamp constraints requested by currently RUNNABLE
> > + * tasks.
> > * When there are no CFS RUNNABLE tasks, clamps are released and
> > * frequency will be gracefully reduced with the utilization decay.
> > */
> > - util = (type == ENERGY_UTIL)
> > - ? util_cfs
> > - : uclamp_util(rq, util_cfs);
> > - util += cpu_util_rt(rq);
> > + util = cpu_util_rt(rq);
> > + if (type == FREQUENCY_UTIL) {
> > + util += cpu_util_cfs(rq);
> > + util = uclamp_util(rq, util);
>
> So with this we don't go to max to anymore for CONFIG_UCLAMP_TASK=n no ?

Mmm... good point!

I need to guard this chagen for the !CONFIG_UCLAMP_TASK case!

>
> Thanks,
> Quentin

Cheers Patrick

--
#include <best/regards.h>

Patrick Bellasi