sched: Track group sched_entity usage contributions

Add usage contribution tracking for group entities. Unlike
se->avg.load_avg_contrib, se->avg.utilization_avg_contrib for group
entities is the sum of se->avg.utilization_avg_contrib for all entities on the
group runqueue.

It is _not_ influenced in any way by the task group h_load. Hence it is
representing the actual cpu usage of the group, not its intended load
contribution which may differ significantly from the utilization on
lightly utilized systems.

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Morten.Rasmussen@arm.com
Cc: Paul Turner <pjt@google.com>
Cc: dietmar.eggemann@arm.com
Cc: efault@gmx.de
Cc: kamalesh@linux.vnet.ibm.com
Cc: linaro-kernel@lists.linaro.org
Cc: nicolas.pitre@linaro.org
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1425052454-25797-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 414408dd..d94a865 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2747,6 +2747,9 @@ static long __update_entity_utilization_avg_contrib(struct sched_entity *se)
 
 	if (entity_is_task(se))
 		__update_task_entity_utilization(se);
+	else
+		se->avg.utilization_avg_contrib =
+					group_cfs_rq(se)->utilization_load_avg;
 
 	return se->avg.utilization_avg_contrib - old_contrib;
 }