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>
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 4240abc..c953a89 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -94,6 +94,7 @@
#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 @@
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);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c5468f..77af759 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1081,20 +1081,63 @@
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 @@
*/
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 @@
* 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) {
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 14b5719..e6539736a 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -222,6 +222,15 @@
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 @@
}
#endif /* CONFIG_64BIT */
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
-
