[RFC][PATCH 12/22] sched: add runtime reporting for -deadline tasks

[Raistlin <raistlin@linux.it>]

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Make it available for the user-space the total amount of runtime
time it has used from since it became a -deadline task.

This is something that is typically useful for monitoring from
user-space the task CPU usage, and maybe implementing at that level
some more sophisticated scheduling behaviour.

One example is feedback scheduling, where you try to adapt the
scheduling parameters of a task by looking at its behaviour in
a certain interval of time, applying concepts coming from control
engineering.

Signed-off-by: Dario Faggioli <raistlin@linux.it>
---
 include/linux/sched.h |    7 +++----
 kernel/sched.c        |    3 +++
 kernel/sched_debug.c  |    1 +
 kernel/sched_dl.c     |    1 +
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8ae947b..b6f0635 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1242,14 +1242,15 @@ struct sched_rt_entity {
 #endif
 };
 
-#ifdef CONFIG_SCHEDSTATS
 struct sched_stats_dl {
+#ifdef CONFIG_SCHEDSTATS
 	u64			last_dmiss;
 	u64			last_rorun;
 	u64			dmiss_max;
 	u64			rorun_max;
-};
 #endif
+	u64			tot_rtime;
+};
 
 struct sched_dl_entity {
 	struct rb_node	rb_node;
@@ -1292,9 +1293,7 @@ struct sched_dl_entity {
 	 */
 	struct hrtimer dl_timer;
 
-#ifdef CONFIG_SCHEDSTATS
 	struct sched_stats_dl stats;
-#endif
 };
 
 struct rcu_node;
diff --git a/kernel/sched.c b/kernel/sched.c
index 63a33f6..19c8c25 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4799,6 +4799,8 @@ __setparam_dl(struct task_struct *p, const struct sched_param_ex *param_ex)
 	dl_se->flags = param_ex->sched_flags;
 	dl_se->dl_throttled = 0;
 	dl_se->dl_new = 1;
+
+	dl_se->stats.tot_rtime = 0;
 }
 
 static void
@@ -4812,6 +4814,7 @@ __getparam_dl(struct task_struct *p, struct sched_param_ex *param_ex)
 	param_ex->sched_period = ns_to_timespec(dl_se->dl_period);
 	param_ex->sched_flags = dl_se->flags;
 	param_ex->curr_runtime = ns_to_timespec(dl_se->runtime);
+	param_ex->used_runtime = ns_to_timespec(dl_se->stats.tot_rtime);
 	param_ex->curr_deadline = ns_to_timespec(dl_se->deadline);
 }
 
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index f685f18..9bec524 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -472,6 +472,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
 		PN(dl.stats.dmiss_max);
 		PN(dl.stats.last_rorun);
 		PN(dl.stats.rorun_max);
+		PN(dl.stats.tot_rtime);
 	}
 
 	{
diff --git a/kernel/sched_dl.c b/kernel/sched_dl.c
index b01aa2a..c4091c9 100644
--- a/kernel/sched_dl.c
+++ b/kernel/sched_dl.c
@@ -535,6 +535,7 @@ static void update_curr_dl(struct rq *rq)
 
 	sched_dl_avg_update(rq, delta_exec);
 
+	dl_se->stats.tot_rtime += delta_exec;
 	dl_se->runtime -= delta_exec;
 	if (dl_runtime_exceeded(rq, dl_se)) {
 		__dequeue_task_dl(rq, curr, 0);
-- 
1.7.2.3


-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa  (Italy)

http://blog.linux.it/raistlin / raistlin@ekiga.net /
dario.faggioli@jabber.org

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