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@linux.intel.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1425961200-3809-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 3fa8fa6d9403..0a81a954c041 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -914,6 +914,12 @@ static void yield_task_dl(struct rq *rq)
         }
         update_rq_clock(rq);
         update_curr_dl(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);
 }
 
 #ifdef CONFIG_SMP