[GIT PULL] scheduler fix
From: Ingo Molnar
Date: Wed Oct 19 2016 - 11:52:30 EST
Please pull the latest sched-urgent-for-linus git tree from:
# HEAD: b5a9b340789b2b24c6896bcf7a065c31a4db671c sched/fair: Fix incorrect task group ->load_avg
This fixes a group scheduling related performance/interactivity regression
introduced in v4.8, which affects certain hardware environments where
cpu_possible_mask != cpu_present_mask.
Vincent Guittot (1):
sched/fair: Fix incorrect task group ->load_avg
kernel/sched/fair.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 76ee7de1859d..d941c97dfbc3 100644
@@ -690,7 +690,14 @@ void init_entity_runnable_average(struct sched_entity *se)
* will definitely be update (after enqueue).
sa->period_contrib = 1023;
- sa->load_avg = scale_load_down(se->load.weight);
+ * Tasks are intialized with full load to be seen as heavy tasks until
+ * they get a chance to stabilize to their real load level.
+ * Group entities are intialized with zero load to reflect the fact that
+ * nothing has been attached to the task group yet.
+ if (entity_is_task(se))
+ sa->load_avg = scale_load_down(se->load.weight);
sa->load_sum = sa->load_avg * LOAD_AVG_MAX;
* At this point, util_avg won't be used in select_task_rq_fair anyway