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SubjectRe: [PATCH v3 2/6] cpufreq: schedutil: ensure max frequency while running RT/DL tasks
On 30/11/17 15:45, Patrick Bellasi wrote:
> On 30-Nov 14:17, Juri Lelli wrote:
> > Hi,
> >
> > On 30/11/17 11:47, Patrick Bellasi wrote:
> >
> > [...]
> >
> > > @@ -340,6 +349,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
> > > struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> > > unsigned long util, max;
> > > unsigned int next_f;
> > > + bool rt_mode;
> > >
> > > sugov_get_util(&util, &max, sg_cpu->cpu);
> > >
> > > @@ -353,17 +363,27 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
> > > sg_cpu->flags = 0;
> > > goto done;
> > > }
> > > - sg_cpu->flags = flags;
> > > +
> > > + /*
> > > + * While RT/DL tasks are running we do not want FAIR tasks to
> > > + * overwrite this CPU's flags, still we can update utilization and
> > > + * frequency (if required/possible) to be fair with these tasks.
> > > + */
> > > + rt_mode = task_has_dl_policy(current) ||
> > > + task_has_rt_policy(current) ||
> > > + (flags & SCHED_CPUFREQ_RT_DL);
> > > + if (rt_mode)
> > > + sg_cpu->flags |= flags;
> > > + else
> > > + sg_cpu->flags = flags;
> > >
> > > sugov_set_iowait_boost(sg_cpu, time, flags);
> > > sg_cpu->last_update = time;
> > >
> > > if (sugov_should_update_freq(sg_policy, time)) {
> > > - if (flags & SCHED_CPUFREQ_RT_DL)
> > > - next_f = sg_policy->policy->cpuinfo.max_freq;
> > > - else
> > > - next_f = sugov_next_freq_shared(sg_cpu, time);
> > > -
> > > + next_f = rt_mode
> > > + ? sg_policy->policy->cpuinfo.max_freq
> > > + : sugov_next_freq_shared(sg_cpu, time);
> > > sugov_update_commit(sg_policy, time, next_f);
> >
> > Aren't we already at max_freq at this point (since an RT/DL task is
> > running)? Do we need to trigger a frequency update?
>
> I think that's required to cover the first time we enter rt_mode in
> order to jump to max OPP.
>
> If we are already at max OPP, sugov_update_commit() will just bail out
> without doing anything.

Indeed!

Best,

Juri

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