[PATCH 2/4] timer: relax tick stop in idle entry

From	Jacob Pan <jacob.jun.pan@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCH 2/4] timer: relax tick stop in idle entry
Date	2015-11-13 21:00 +0100
Message-ID	<qusFP-2eI-1@gated-at.bofh.it> (permalink)
References	<qusFP-2eI-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

Upon entering idle, we can turn off tick if the next timeout
is exactly one tick away. Otherwise, we could enter inner idle loop
with tick still enabled, without resched set, the tick will continue
during idle therefore less optimal in terms of energy savings.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 kernel/time/tick-sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7c7ec45..bcadaab 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -606,7 +606,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
 	 * restart it proper.
 	 */
 	delta = next_tick - basemono;
-	if (delta <= (u64)TICK_NSEC) {
+	if (delta < (u64)TICK_NSEC) {
 		tick.tv64 = 0;
 		if (!ts->tick_stopped)
 			goto out;
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH 2/4] timer: relax tick stop in idle entry Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-13 21:00 +0100
  Re: [PATCH 2/4] timer: relax tick stop in idle entry Thomas Gleixner <tglx@linutronix.de> - 2015-11-13 21:30 +0100
    Re: [PATCH 2/4] timer: relax tick stop in idle entry Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-13 23:30 +0100

csiph-web