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[RFC,v2,2/2] power/idle: enhance the precision of sleep_length

Message ID 57591c5e.582b620a.f8dc2.19dd@mx.google.com (mailing list archive)
State RFC, archived
Headers show

Commit Message

Zhaoyang Huang June 9, 2016, 7:34 a.m. UTC 
From: Zhaoyang Huang <zhaoyang.huang@spreadtrum.com>

There should be a gap between tick_nohz_idle_enter and
tick_nohz_get_sleep_length when idle, which will cause the
sleep_length is not very precised. Change it in this patch.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@spreadtrum.com>
---
 kernel/time/tick-sched.c |    5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 536ada8..ee3be3d 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -975,6 +975,11 @@  void tick_nohz_irq_exit(void)
 ktime_t tick_nohz_get_sleep_length(void)
 {
 	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
+	ktime_t now;
+
+	now = ktime_get();
+	ts->sleep_length = ktime_sub(dev->next_event, now);
 
 	return ts->sleep_length;
 }