diff options
| author | Juri Lelli <juri.lelli@arm.com> | 2015-07-07 19:24:24 +0100 |
|---|---|---|
| committer | Vincent Guittot <vincent.guittot@linaro.org> | 2015-07-27 17:59:43 +0200 |
| commit | ab6a4acc9b002ef292a977f0c52d3672d6451fe1 (patch) | |
| tree | 70f483f03c9575355cc417df402920276acd61bb | |
| parent | 1f450e1bfeff66d2084b0df3edb305b02a885120 (diff) | |
sched/fair: add triggers for OPP change requests
Each time a task is {en,de}queued we might need to adapt the current
frequency to the new usage. Add triggers on {en,de}queue_task_fair() for
this purpose. Only trigger a freq request if we are effectively waking up
or going to sleep. Filter out load balancing related calls to reduce the
number of triggers.
cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
| -rw-r--r-- | kernel/sched/fair.c | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5e1268438a43..a70d2d0ad65a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4261,7 +4261,10 @@ static inline void hrtick_update(struct rq *rq) } #endif +static unsigned int capacity_margin = 1280; /* ~20% margin */ + static bool cpu_overutilized(int cpu); +static unsigned long get_cpu_usage(int cpu); struct static_key __sched_energy_freq __read_mostly = STATIC_KEY_INIT_FALSE; /* @@ -4312,6 +4315,26 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (!task_new && !rq->rd->overutilized && cpu_overutilized(rq->cpu)) rq->rd->overutilized = true; + /* + * We want to trigger a freq switch request only for tasks that + * are waking up; this is because we get here also during + * load balancing, but in these cases it seems wise to trigger + * as single request after load balancing is done. + * + * XXX: how about fork()? Do we need a special flag/something + * to tell if we are here after a fork() (wakeup_task_new)? + * + * Also, we add a margin (same ~20% used for the tipping point) + * to our request to provide some head room if p's utilization + * further increases. + */ + if (sched_energy_freq() && !task_new) { + unsigned long req_cap = get_cpu_usage(cpu_of(rq)); + + req_cap = req_cap * capacity_margin + >> SCHED_CAPACITY_SHIFT; + cpufreq_sched_set_cap(cpu_of(rq), req_cap); + } } hrtick_update(rq); } @@ -4373,6 +4396,23 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (!se) { sub_nr_running(rq, 1); update_rq_runnable_avg(rq, 1); + /* + * We want to trigger a freq switch request only for tasks that + * are going to sleep; this is because we get here also during + * load balancing, but in these cases it seems wise to trigger + * as single request after load balancing is done. + * + * Also, we add a margin (same ~20% used for the tipping point) + * to our request to provide some head room if p's utilization + * further increases. + */ + if (sched_energy_freq() && task_sleep) { + unsigned long req_cap = get_cpu_usage(cpu_of(rq)); + + req_cap = req_cap * capacity_margin + >> SCHED_CAPACITY_SHIFT; + cpufreq_sched_set_cap(cpu_of(rq), req_cap); + } } hrtick_update(rq); } @@ -4939,8 +4979,6 @@ static int find_new_capacity(struct energy_env *eenv, return idx; } -static unsigned int capacity_margin = 1280; /* ~20% margin */ - static bool cpu_overutilized(int cpu) { return (capacity_of(cpu) * 1024) < |