[tip:sched/core] sched/deadline: Add rq-> clock update skip for dl task yield

From: tip-bot for Wanpeng Li
Date: Tue Mar 10 2015 - 06:08:39 EST

Commit-ID: 44fb085bfa17628c6d2aaa6af6b292a8499e9cbd
Gitweb: http://git.kernel.org/tip/44fb085bfa17628c6d2aaa6af6b292a8499e9cbd
Author: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 10 Mar 2015 12:20:00 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 10 Mar 2015 05:46:50 +0100

sched/deadline: Add rq->clock update skip for dl task yield

This patch adds rq->clock update skip for SCHED_DEADLINE task yield,
to tell update_rq_clock() that we've just updated the clock, so that
we don't do a microscopic update in schedule() and double the
fastpath cost.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1425961200-3809-1-git-send-email-wanpeng.li@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
kernel/sched/deadline.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 3fa8fa6..0a81a95 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -914,6 +914,12 @@ static void yield_task_dl(struct rq *rq)
+ /*
+ * Tell update_rq_clock() that we've just updated,
+ * so we don't do microscopic update in schedule()
+ * and double the fastpath cost.
+ */
+ rq_clock_skip_update(rq, true);

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