Commit 523e979d authored by Vincent Guittot's avatar Vincent Guittot Committed by Ingo Molnar

sched/core: Use PELT for scale_rt_capacity()

The utilization of the CPU by RT, DL and IRQs are now tracked with
PELT so we can use these metrics instead of rt_avg to evaluate the remaining
capacity available for CFS class.

scale_rt_capacity() behavior has been changed and now returns the remaining
capacity available for CFS instead of a scaling factor because RT, DL and
IRQ provide now absolute utilization value.

The same formula as schedutil is used:

  IRQ util_avg + (1 - IRQ util_avg / max capacity ) * /Sum rq util_avg

but the implementation is different because it doesn't return the same value
and doesn't benefit of the same optimization.
Signed-off-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: claudio@evidence.eu.com
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: joel@joelfernandes.org
Cc: juri.lelli@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: patrick.bellasi@arm.com
Cc: quentin.perret@arm.com
Cc: rjw@rjwysocki.net
Cc: valentin.schneider@arm.com
Cc: viresh.kumar@linaro.org
Link: http://lkml.kernel.org/r/1530200714-4504-10-git-send-email-vincent.guittot@linaro.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent dfa444dc
......@@ -1180,8 +1180,6 @@ static void update_curr_dl(struct rq *rq)
curr->se.exec_start = now;
cgroup_account_cputime(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);
if (dl_entity_is_special(dl_se))
return;
......
......@@ -7551,39 +7551,39 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
static unsigned long scale_rt_capacity(int cpu)
{
struct rq *rq = cpu_rq(cpu);
u64 total, used, age_stamp, avg;
s64 delta;
/*
* Since we're reading these variables without serialization make sure
* we read them once before doing sanity checks on them.
*/
age_stamp = READ_ONCE(rq->age_stamp);
avg = READ_ONCE(rq->rt_avg);
delta = __rq_clock_broken(rq) - age_stamp;
unsigned long max = arch_scale_cpu_capacity(NULL, cpu);
unsigned long used, free;
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
unsigned long irq;
#endif
if (unlikely(delta < 0))
delta = 0;
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
irq = READ_ONCE(rq->avg_irq.util_avg);
total = sched_avg_period() + delta;
if (unlikely(irq >= max))
return 1;
#endif
used = div_u64(avg, total);
used = READ_ONCE(rq->avg_rt.util_avg);
used += READ_ONCE(rq->avg_dl.util_avg);
if (likely(used < SCHED_CAPACITY_SCALE))
return SCHED_CAPACITY_SCALE - used;
if (unlikely(used >= max))
return 1;
return 1;
free = max - used;
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
free *= (max - irq);
free /= max;
#endif
return free;
}
static void update_cpu_capacity(struct sched_domain *sd, int cpu)
{
unsigned long capacity = arch_scale_cpu_capacity(sd, cpu);
unsigned long capacity = scale_rt_capacity(cpu);
struct sched_group *sdg = sd->groups;
cpu_rq(cpu)->cpu_capacity_orig = capacity;
capacity *= scale_rt_capacity(cpu);
capacity >>= SCHED_CAPACITY_SHIFT;
cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(sd, cpu);
if (!capacity)
capacity = 1;
......
......@@ -237,7 +237,7 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runna
*/
sa->load_avg = div_u64(load * sa->load_sum, divider);
sa->runnable_load_avg = div_u64(runnable * sa->runnable_load_sum, divider);
sa->util_avg = sa->util_sum / divider;
WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
}
/*
......
......@@ -973,8 +973,6 @@ static void update_curr_rt(struct rq *rq)
curr->se.exec_start = now;
cgroup_account_cputime(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);
if (!rt_bandwidth_enabled())
return;
......
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