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.ku...@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
