Re: [PATCH v3 1/6] measure exec_clock for rt sched entities

On 05/30/2012 02:29 PM, Peter Zijlstra wrote:

On Wed, 2012-05-30 at 13:48 +0400, Glauber Costa wrote:

quoted

For simetry with the cfq tasks, measure exec_clock for the rt
sched entities (rt_se).

Symmetry methinks..

=p bad me

anyway, where is the symmetry?, fair.c:update_curr()
doesn't do the for_each_sched_entity() thing.

It does implicitly, because fair.c:update_curr() is called from
within enqueue_task(), that is called for_each_sched_entity in
enqueue_task_fair().

quoted

This can be used in a number of fashions. For instance, to
compute total cpu usage in a cgroup that is generated by
rt tasks.

Signed-off-by: Glauber Costa<redacted>
CC: Peter Zijlstra<a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
CC: Paul Turner<redacted>
---
  kernel/sched/rt.c    |    5 +++++
  kernel/sched/sched.h |    1 +
  2 files changed, 6 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index c5565c3..30ee4e2 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c

@@ -919,6 +919,11 @@ static void update_curr_rt(struct rq *rq)

  	sched_rt_avg_update(rq, delta_exec);

+	for_each_sched_rt_entity(rt_se) {
+		rt_rq = rt_rq_of_se(rt_se);
+		schedstat_add(rt_rq, exec_clock, delta_exec);
+	}
+
  	if (!rt_bandwidth_enabled())
  		return;

See, this just makes me sad.. you now have a double
for_each_sched_rt_entity() loop.

The way I read the rt.c code, it it is called from enqueue_task_rt only 
once.