On Wed, May 30, 2012 at 2:48 AM, Glauber Costa<glommer@xxxxxxxxxxxxx> wrote:When we're dealing with a task group, instead of a task, also record
the start of its sleep time. Since the test agains TASK_UNINTERRUPTIBLE
does not really make sense and lack an obvious analogous, we always
record it as sleep_start, never block_start.
Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
CC: Peter Zijlstra<a.p.zijlstra@xxxxxxxxx>
CC: Paul Turner<pjt@xxxxxxxxxx>
---
kernel/sched/fair.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c26fe38..d932559 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1182,7 +1182,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
se->statistics.sleep_start = rq_of(cfs_rq)->clock;
if (tsk->state& TASK_UNINTERRUPTIBLE)
se->statistics.block_start = rq_of(cfs_rq)->clock;
- }
+ } else
+ se->statistics.sleep_start = rq_of(cfs_rq)->clock;
You can't sanely account sleep on a group entity.
Suppose you have 2 sleepers on 1 cpu: you account 1s/s of idle
Suppose you have 2 sleepers now on 2 cpus: you account 2s/s of idle
Furthermore, in the latter case when one wakes up you still continue
to accrue sleep time whereas in the former you don't.
Just don't report/collect this.
#endif
}
--
1.7.10.2