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sched/fair: add triggers for OPP change requests

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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.

[smuckle@linaro.org: resolve merge conflicts, define task_new,
 use renamed static key sched_freq]

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Steve Muckle <smuckle@linaro.org>
This commit is contained in:
Juri Lelli 2015-08-19 19:47:12 +01:00 • committed by Leo Yan
parent a967a45c71
commit ea429ccef1
1 changed files with 45 additions and 1 deletions
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46
kernel/sched/fair.c
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@ -4144,6 +4144,21 @@ static inline void hrtick_update(struct rq *rq)
} }
#endif #endif
static unsigned long capacity_orig_of(int cpu);
static int cpu_util(int cpu);
static void update_capacity_of(int cpu)
{
unsigned long req_cap;
if (!sched_freq())
return;
/* Convert scale-invariant capacity to cpu. */
req_cap = cpu_util(cpu) * SCHED_CAPACITY_SCALE / capacity_orig_of(cpu);
set_cfs_cpu_capacity(cpu, true, req_cap);
}
static bool cpu_overutilized(int cpu); static bool cpu_overutilized(int cpu);
/* /*
@ -4193,6 +4208,20 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
if (!task_new && !rq->rd->overutilized && if (!task_new && !rq->rd->overutilized &&
cpu_overutilized(rq->cpu)) cpu_overutilized(rq->cpu))
rq->rd->overutilized = true; rq->rd->overutilized = true;
/*
* We want to potentially 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)?
*/
if (!task_new)
update_capacity_of(cpu_of(rq));
} }
hrtick_update(rq); hrtick_update(rq);
} }
@ -4251,9 +4280,24 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_cfs_shares(cfs_rq); update_cfs_shares(cfs_rq);
} }
if (!se) if (!se) {
sub_nr_running(rq, 1); sub_nr_running(rq, 1);
/*
* We want to potentially 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.
*/
if (task_sleep) {
if (rq->cfs.nr_running)
update_capacity_of(cpu_of(rq));
else if (sched_freq())
set_cfs_cpu_capacity(cpu_of(rq), false, 0);
}
}
hrtick_update(rq); hrtick_update(rq);
} }