sched: Aggregate load contributed by task entities on parenting cfs_rq

For a given task t, we can compute its contribution to load as:

  task_load(t) = runnable_avg(t) * weight(t)

On a parenting cfs_rq we can then aggregate:

  runnable_load(cfs_rq) = \Sum task_load(t), for all runnable children t

Maintain this bottom up, with task entities adding their contributed load to
the parenting cfs_rq sum.  When a task entity's load changes we add the same
delta to the maintained sum.

Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.514678907@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Paul Turner 2012-10-04 13:18:30 +02:00 committed by Ingo Molnar
parent 18bf2805d9
commit 2dac754e10
4 changed files with 60 additions and 5 deletions

View File

@ -1103,6 +1103,7 @@ struct sched_avg {
*/
u32 runnable_avg_sum, runnable_avg_period;
u64 last_runnable_update;
unsigned long load_avg_contrib;
};
#ifdef CONFIG_SCHEDSTATS

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@ -94,6 +94,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
#ifdef CONFIG_SMP
P(se->avg.runnable_avg_sum);
P(se->avg.runnable_avg_period);
P(se->avg.load_avg_contrib);
#endif
#undef PN
#undef P
@ -224,6 +225,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
cfs_rq->load_contribution);
SEQ_printf(m, " .%-30s: %d\n", "load_tg",
atomic_read(&cfs_rq->tg->load_weight));
SEQ_printf(m, " .%-30s: %lld\n", "runnable_load_avg",
cfs_rq->runnable_load_avg);
#endif
print_cfs_group_stats(m, cpu, cfs_rq->tg);

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@ -1081,20 +1081,63 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
return decayed;
}
/* Compute the current contribution to load_avg by se, return any delta */
static long __update_entity_load_avg_contrib(struct sched_entity *se)
{
long old_contrib = se->avg.load_avg_contrib;
if (!entity_is_task(se))
return 0;
se->avg.load_avg_contrib = div64_u64(se->avg.runnable_avg_sum *
se->load.weight,
se->avg.runnable_avg_period + 1);
return se->avg.load_avg_contrib - old_contrib;
}
/* Update a sched_entity's runnable average */
static inline void update_entity_load_avg(struct sched_entity *se)
{
__update_entity_runnable_avg(rq_of(cfs_rq_of(se))->clock_task, &se->avg,
se->on_rq);
struct cfs_rq *cfs_rq = cfs_rq_of(se);
long contrib_delta;
if (!__update_entity_runnable_avg(rq_of(cfs_rq)->clock_task, &se->avg,
se->on_rq))
return;
contrib_delta = __update_entity_load_avg_contrib(se);
if (se->on_rq)
cfs_rq->runnable_load_avg += contrib_delta;
}
static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
{
__update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
}
/* Add the load generated by se into cfs_rq's child load-average */
static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq,
struct sched_entity *se)
{
update_entity_load_avg(se);
cfs_rq->runnable_load_avg += se->avg.load_avg_contrib;
}
/* Remove se's load from this cfs_rq child load-average */
static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq,
struct sched_entity *se)
{
update_entity_load_avg(se);
cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib;
}
#else
static inline void update_entity_load_avg(struct sched_entity *se) {}
static inline void update_rq_runnable_avg(struct rq *rq, int runnable) {}
static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq,
struct sched_entity *se) {}
static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq,
struct sched_entity *se) {}
#endif
static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
@ -1223,7 +1266,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
*/
update_curr(cfs_rq);
update_cfs_load(cfs_rq, 0);
update_entity_load_avg(se);
enqueue_entity_load_avg(cfs_rq, se);
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
@ -1298,7 +1341,7 @@ 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_entity_load_avg(se);
dequeue_entity_load_avg(cfs_rq, se);
update_stats_dequeue(cfs_rq, se);
if (flags & DEQUEUE_SLEEP) {

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@ -222,6 +222,15 @@ struct cfs_rq {
unsigned int nr_spread_over;
#endif
#ifdef CONFIG_SMP
/*
* CFS Load tracking
* Under CFS, load is tracked on a per-entity basis and aggregated up.
* This allows for the description of both thread and group usage (in
* the FAIR_GROUP_SCHED case).
*/
u64 runnable_load_avg;
#endif
#ifdef CONFIG_FAIR_GROUP_SCHED
struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
@ -1214,4 +1223,3 @@ static inline u64 irq_time_read(int cpu)
}
#endif /* CONFIG_64BIT */
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */