linux-kernel - [RFC] sched: make update_cpu_load

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Message-Id: <1439458524-14145-1-git-send-email-byungchul.park@lge.com>
Date:	Thu, 13 Aug 2015 18:35:24 +0900
From:	byungchul.park@....com
To:	mingo@...nel.org, peterz@...radead.org
Cc:	linux-kernel@...r.kernel.org,
	Byungchul Park <byungchul.park@....com>
Subject: [RFC] sched: make update_cpu_load_active care more than one tick

From: Byungchul Park <byungchul.park@....com>

i found do_timer accounts other than one tick, so i made
update_cpu_load_active care that.

is it intended because of its overhead?

Signed-off-by: Byungchul Park <byungchul.park@....com>
---
 kernel/sched/fair.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ffa70dc..cd3d98f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4506,12 +4506,15 @@ void update_cpu_load_nohz(void)
  */
 void update_cpu_load_active(struct rq *this_rq)
 {
+	unsigned long curr_jiffies = READ_ONCE(jiffies);
+	unsigned long pending_updates;
 	unsigned long load = this_rq->cfs.runnable_load_avg;
 	/*
 	 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
 	 */
-	this_rq->last_load_update_tick = jiffies;
-	__update_cpu_load(this_rq, load, 1);
+	pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+	this_rq->last_load_update_tick = curr_jiffies;
+	__update_cpu_load(this_rq, load, pending_updates);
 }
 
 /* Used instead of source_load when we know the type == 0 */
-- 
1.7.9.5

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