[PATCH 3/7 v3] sched: factorize PELT update
From: Vincent Guittot
Date: Mon Sep 12 2016 - 03:48:41 EST
Every time, we modify load/utilization of sched_entity, we start to sync
it with its cfs_rq. This update is done is different ways:
-when attaching/detaching a sched_entity, we update cfs_rq and then we
sync the entity with the cfs_rq.
-when enqueueing/dequeuing the sched_entity, we update both sched_entity
and cfs_rq metrics to now.
Use update_load_avg everytime we have to update and sync cfs_rq and
sched_entity before changing the state of a sched_enity
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
---
kernel/sched/fair.c | 68 ++++++++++++++---------------------------------------
1 file changed, 17 insertions(+), 51 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 264119a..0aa1d7d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3086,7 +3086,8 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
}
/* Update task and its cfs_rq load average */
-static inline void update_load_avg(struct sched_entity *se, int update_tg)
+static inline void update_load_avg(struct sched_entity *se, int update_tg,
+ int skip_aging)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
@@ -3097,7 +3098,8 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
* Track task load average for carrying it to new CPU after migrated, and
* track group sched_entity load average for task_h_load calc in migration
*/
- __update_load_avg(now, cpu, &se->avg,
+ if (se->avg.last_update_time && !skip_aging)
+ __update_load_avg(now, cpu, &se->avg,
se->on_rq * scale_load_down(se->load.weight),
cfs_rq->curr == se, NULL);
@@ -3115,26 +3117,6 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
*/
static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- if (!sched_feat(ATTACH_AGE_LOAD))
- goto skip_aging;
-
- /*
- * If we got migrated (either between CPUs or between cgroups) we'll
- * have aged the average right before clearing @last_update_time.
- *
- * Or we're fresh through post_init_entity_util_avg().
- */
- if (se->avg.last_update_time) {
- __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
- &se->avg, 0, 0, NULL);
-
- /*
- * XXX: we could have just aged the entire load away if we've been
- * absent from the fair class for too long.
- */
- }
-
-skip_aging:
se->avg.last_update_time = cfs_rq->avg.last_update_time;
cfs_rq->avg.load_avg += se->avg.load_avg;
cfs_rq->avg.load_sum += se->avg.load_sum;
@@ -3154,9 +3136,6 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
*/
static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
- &se->avg, se->on_rq * scale_load_down(se->load.weight),
- cfs_rq->curr == se, NULL);
sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
sub_positive(&cfs_rq->avg.load_sum, se->avg.load_sum);
@@ -3171,34 +3150,20 @@ static inline void
enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct sched_avg *sa = &se->avg;
- u64 now = cfs_rq_clock_task(cfs_rq);
- int migrated, decayed;
-
- migrated = !sa->last_update_time;
- if (!migrated) {
- __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
- se->on_rq * scale_load_down(se->load.weight),
- cfs_rq->curr == se, NULL);
- }
-
- decayed = update_cfs_rq_load_avg(now, cfs_rq, !migrated);
cfs_rq->runnable_load_avg += sa->load_avg;
cfs_rq->runnable_load_sum += sa->load_sum;
- if (migrated)
+ if (!sa->last_update_time) {
attach_entity_load_avg(cfs_rq, se);
-
- if (decayed || migrated)
update_tg_load_avg(cfs_rq, 0);
+ }
}
/* Remove the runnable load generated by se from cfs_rq's runnable load average */
static inline void
dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- update_load_avg(se, 1);
-
cfs_rq->runnable_load_avg =
max_t(long, cfs_rq->runnable_load_avg - se->avg.load_avg, 0);
cfs_rq->runnable_load_sum =
@@ -3272,7 +3237,8 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
return 0;
}
-static inline void update_load_avg(struct sched_entity *se, int not_used)
+static inline void update_load_avg(struct sched_entity *se,
+ int not_used1, int not_used2)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
struct rq *rq = rq_of(cfs_rq);
@@ -3420,6 +3386,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
if (renorm && !curr)
se->vruntime += cfs_rq->min_vruntime;
+ update_load_avg(se, 1, 0);
enqueue_entity_load_avg(cfs_rq, se);
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
@@ -3494,6 +3461,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
* Update run-time statistics of the 'current'.
*/
update_curr(cfs_rq);
+ update_load_avg(se, 1, 0);
dequeue_entity_load_avg(cfs_rq, se);
update_stats_dequeue(cfs_rq, se, flags);
@@ -3572,7 +3540,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
*/
update_stats_wait_end(cfs_rq, se);
__dequeue_entity(cfs_rq, se);
- update_load_avg(se, 1);
+ update_load_avg(se, 1, 0);
}
update_stats_curr_start(cfs_rq, se);
@@ -3674,7 +3642,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
/* Put 'current' back into the tree. */
__enqueue_entity(cfs_rq, prev);
/* in !on_rq case, update occurred at dequeue */
- update_load_avg(prev, 0);
+ update_load_avg(prev, 0, 0);
}
cfs_rq->curr = NULL;
}
@@ -3690,7 +3658,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
/*
* Ensure that runnable average is periodically updated.
*/
- update_load_avg(curr, 1);
+ update_load_avg(curr, 1, 0);
update_cfs_shares(cfs_rq);
#ifdef CONFIG_SCHED_HRTICK
@@ -4579,7 +4547,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
if (cfs_rq_throttled(cfs_rq))
break;
- update_load_avg(se, 1);
+ update_load_avg(se, 1, 0);
update_cfs_shares(cfs_rq);
}
@@ -4638,7 +4606,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
if (cfs_rq_throttled(cfs_rq))
break;
- update_load_avg(se, 1);
+ update_load_avg(se, 1, 0);
update_cfs_shares(cfs_rq);
}
@@ -8517,7 +8485,6 @@ static void detach_task_cfs_rq(struct task_struct *p)
{
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- u64 now = cfs_rq_clock_task(cfs_rq);
if (!vruntime_normalized(p)) {
/*
@@ -8529,7 +8496,7 @@ static void detach_task_cfs_rq(struct task_struct *p)
}
/* Catch up with the cfs_rq and remove our load when we leave */
- update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_load_avg(se, 0, 0);
detach_entity_load_avg(cfs_rq, se);
update_tg_load_avg(cfs_rq, false);
}
@@ -8537,7 +8504,6 @@ static void detach_task_cfs_rq(struct task_struct *p)
static void attach_entity_cfs_rq(struct sched_entity *se)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- u64 now = cfs_rq_clock_task(cfs_rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
@@ -8548,7 +8514,7 @@ static void attach_entity_cfs_rq(struct sched_entity *se)
#endif
/* Synchronize task with its cfs_rq */
- update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_load_avg(se, 0, !sched_feat(ATTACH_AGE_LOAD));
attach_entity_load_avg(cfs_rq, se);
update_tg_load_avg(cfs_rq, false);
}
--
1.9.1