From 34e2c555f3e13c90e9284e23d00f03be8a6e06c5 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 15 Feb 2016 20:20:42 +0100 Subject: cpufreq: Add mechanism for registering utilization update callbacks Introduce a mechanism by which parts of the cpufreq subsystem ("setpolicy" drivers or the core) can register callbacks to be executed from cpufreq_update_util() which is invoked by the scheduler's update_load_avg() on CPU utilization changes. This allows the "setpolicy" drivers to dispense with their timers and do all of the computations they need and frequency/voltage adjustments in the update_load_avg() code path, among other things. The update_load_avg() changes were suggested by Peter Zijlstra. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Acked-by: Peter Zijlstra (Intel) Acked-by: Ingo Molnar --- kernel/sched/deadline.c | 4 ++++ kernel/sched/fair.c | 26 +++++++++++++++++++++++++- kernel/sched/rt.c | 4 ++++ kernel/sched/sched.h | 1 + 4 files changed, 34 insertions(+), 1 deletion(-) (limited to 'kernel/sched') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index cd64c979d0e1..21a0aa6f810d 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -726,6 +726,10 @@ static void update_curr_dl(struct rq *rq) if (!dl_task(curr) || !on_dl_rq(dl_se)) return; + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + /* * Consumed budget is computed considering the time as * observed by schedulable tasks (excluding time spent diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 56b7d4b83947..e2987a7e489d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2824,7 +2824,8 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) { struct cfs_rq *cfs_rq = cfs_rq_of(se); u64 now = cfs_rq_clock_task(cfs_rq); - int cpu = cpu_of(rq_of(cfs_rq)); + struct rq *rq = rq_of(cfs_rq); + int cpu = cpu_of(rq); /* * Track task load average for carrying it to new CPU after migrated, and @@ -2836,6 +2837,29 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg) update_tg_load_avg(cfs_rq, 0); + + if (cpu == smp_processor_id() && &rq->cfs == cfs_rq) { + unsigned long max = rq->cpu_capacity_orig; + + /* + * There are a few boundary cases this might miss but it should + * get called often enough that that should (hopefully) not be + * a real problem -- added to that it only calls on the local + * CPU, so if we enqueue remotely we'll miss an update, but + * the next tick/schedule should update. + * + * It will not get called when we go idle, because the idle + * thread is a different class (!fair), nor will the utilization + * number include things like RT tasks. + * + * As is, the util number is not freq-invariant (we'd have to + * implement arch_scale_freq_capacity() for that). + * + * See cpu_util(). + */ + cpufreq_update_util(rq_clock(rq), + min(cfs_rq->avg.util_avg, max), max); + } } static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 8ec86abe0ea1..27f5b03cbdbe 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -945,6 +945,10 @@ static void update_curr_rt(struct rq *rq) if (curr->sched_class != &rt_sched_class) return; + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_trigger_update(rq_clock(rq)); + delta_exec = rq_clock_task(rq) - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 10f16374df7f..f042190c8002 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -9,6 +9,7 @@ #include #include #include +#include #include "cpupri.h" #include "cpudeadline.h" -- cgit v1.2.3