Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH V4 1/3] sched: cpufreq: Allow remote cpufreq callbacks | Date | Wed, 26 Jul 2017 19:42:01 +0200 |
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On Wednesday, July 26, 2017 02:52:32 PM Viresh Kumar wrote: > We do not call cpufreq callbacks from scheduler core for remote > (non-local) CPUs currently. But there are cases where such remote > callbacks are useful, specially in the case of shared cpufreq policies. > > This patch updates the scheduler core to call the cpufreq callbacks for > remote CPUs as well. > > For now, all the registered utilization update callbacks are updated to > return early if remote callback is detected. That is, this patch just > moves the decision making down in the hierarchy. > > Later patches would enable remote callbacks for shared policies. > > Based on initial work from Steve Muckle. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/cpufreq_governor.c | 4 ++++ > drivers/cpufreq/intel_pstate.c | 8 ++++++++ > include/linux/sched/cpufreq.h | 1 + > kernel/sched/cpufreq.c | 1 + > kernel/sched/cpufreq_schedutil.c | 11 ++++++++--- > kernel/sched/deadline.c | 2 +- > kernel/sched/fair.c | 8 +++++--- > kernel/sched/rt.c | 2 +- > kernel/sched/sched.h | 10 ++-------- > 9 files changed, 31 insertions(+), 16 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c > index eed069ecfd5e..5499796cf9a8 100644 > --- a/drivers/cpufreq/cpufreq_governor.c > +++ b/drivers/cpufreq/cpufreq_governor.c > @@ -272,6 +272,10 @@ static void dbs_update_util_handler(struct update_util_data *data, u64 time, > struct policy_dbs_info *policy_dbs = cdbs->policy_dbs; > u64 delta_ns, lst; > > + /* Don't allow remote callbacks */ > + if (smp_processor_id() != data->cpu) > + return; > + > /* > * The work may not be allowed to be queued up right now. > * Possible reasons: > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 89bbc0c11b22..0dd14c8edd2d 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -1747,6 +1747,10 @@ static void intel_pstate_update_util_pid(struct update_util_data *data, > struct cpudata *cpu = container_of(data, struct cpudata, update_util); > u64 delta_ns = time - cpu->sample.time; > > + /* Don't allow remote callbacks */ > + if (smp_processor_id() != data->cpu) > + return;
You can do this check against cpu->cpu, however.
> + > if ((s64)delta_ns < pid_params.sample_rate_ns) > return; > > @@ -1764,6 +1768,10 @@ static void intel_pstate_update_util(struct update_util_data *data, u64 time, > struct cpudata *cpu = container_of(data, struct cpudata, update_util); > u64 delta_ns; > > + /* Don't allow remote callbacks */ > + if (smp_processor_id() != data->cpu) > + return;
And same here.
> + > if (flags & SCHED_CPUFREQ_IOWAIT) { > cpu->iowait_boost = int_tofp(1); > } else if (cpu->iowait_boost) { > diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h > index d2be2ccbb372..8256a8f35f22 100644 > --- a/include/linux/sched/cpufreq.h > +++ b/include/linux/sched/cpufreq.h > @@ -16,6 +16,7 @@ > #ifdef CONFIG_CPU_FREQ > struct update_util_data { > void (*func)(struct update_util_data *data, u64 time, unsigned int flags); > + unsigned int cpu;
So it looks like you don't need this.
schedutil doesn't need it as per patch [2/3].
ondemand/conservative don't need it as per patch [3/3]
intel_pstate doesn't need this too, because of the above.
Thanks, Rafael
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