linux-kernel - [PATCH 4/4] sched/fair: Add schedstat debug values for REBALANCE

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Date:	Mon, 20 Jun 2016 14:15:14 +0200
From:	Jiri Olsa <jolsa@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	James Hartsock <hartsjc@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Kirill Tkhai <ktkhai@...allels.com>
Subject: [PATCH 4/4] sched/fair: Add schedstat debug values for REBALANCE_AFFINITY

It was helpful to watch several stats when testing
this feature. Adding the most useful.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 include/linux/sched.h |  2 ++
 kernel/sched/debug.c  |  4 ++++
 kernel/sched/fair.c   | 15 ++++++++++++++-
 kernel/sched/sched.h  |  5 +++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0e6ac882283b..4b772820436b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1305,6 +1305,8 @@ struct sched_statistics {
 	u64			nr_failed_migrations_running;
 	u64			nr_failed_migrations_hot;
 	u64			nr_forced_migrations;
+	u64			nr_dont_balance;
+	u64			nr_balanced_affinity;
 
 	u64			nr_wakeups;
 	u64			nr_wakeups_sync;
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2a0a9995256d..5947558dab65 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -635,6 +635,9 @@ do {									\
 		P(sched_goidle);
 		P(ttwu_count);
 		P(ttwu_local);
+		P(nr_dont_balance);
+		P(nr_affinity_out);
+		P(nr_affinity_in);
 	}
 
 #undef P
@@ -912,6 +915,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
 		P(se.statistics.nr_wakeups_affine_attempts);
 		P(se.statistics.nr_wakeups_passive);
 		P(se.statistics.nr_wakeups_idle);
+		P(se.statistics.nr_dont_balance);
 
 		avg_atom = p->se.sum_exec_runtime;
 		if (nr_switches)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 736e525e189c..a4f1ed403f1e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -902,7 +902,15 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
 
 static bool dont_balance(struct task_struct *p)
 {
-	return sched_feat(REBALANCE_AFFINITY) && p->se.dont_balance;
+	bool dont_balance = false;
+
+	if (sched_feat(REBALANCE_AFFINITY) && p->se.dont_balance) {
+		dont_balance = true;
+		schedstat_inc(task_rq(p), nr_dont_balance);
+		schedstat_inc(p, se.statistics.nr_dont_balance);
+	}
+
+	return dont_balance;
 }
 
 /**************************************************
@@ -7903,6 +7911,7 @@ static void rebalance_affinity(struct rq *rq)
 		if (cpu >= nr_cpu_ids)
 			continue;
 
+		schedstat_inc(rq, nr_affinity_out);
 		__detach_task(p, rq, cpu);
 		raw_spin_unlock(&rq->lock);
 
@@ -7911,6 +7920,10 @@ static void rebalance_affinity(struct rq *rq)
 		raw_spin_lock(&dst_rq->lock);
 		attach_task(dst_rq, p);
 		p->se.dont_balance = true;
+
+		schedstat_inc(p, se.statistics.nr_balanced_affinity);
+		schedstat_inc(dst_rq, nr_affinity_in);
+
 		raw_spin_unlock(&dst_rq->lock);
 
 		local_irq_restore(flags);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index d1a6224cd140..f086e233f7e6 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -701,6 +701,11 @@ struct rq {
 	/* try_to_wake_up() stats */
 	unsigned int ttwu_count;
 	unsigned int ttwu_local;
+
+	/* rebalance_affinity() stats */
+	unsigned int nr_dont_balance;
+	unsigned int nr_affinity_out;
+	unsigned int nr_affinity_in;
 #endif
 
 #ifdef CONFIG_SMP
-- 
2.4.11