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authorPeter Zijlstra <peterz@infradead.org>2017-04-21 13:43:59 +0300
committerIngo Molnar <mingo@kernel.org>2017-05-15 11:15:20 +0300
commitf9fccdb9efef60dbcf84d493514b475c41aa866f (patch)
tree3d5278febf2aa2f0d8d2e05977c59bcd97fce350 /kernel/sched/clock.c
parent3067a33d5fec856bb297d58e7f03411d060ccdee (diff)
downloadlinux-f9fccdb9efef60dbcf84d493514b475c41aa866f.tar.xz
cpuidle: Fix idle time tracking
Ville reported that on his Core2, which has TSC stop in idle, we would always report very short idle durations. He tracked this down to commit: e93e59ce5b85 ("cpuidle: Replace ktime_get() with local_clock()") which replaces ktime_get() with local_clock(). Add a sched_clock_idle_wakeup_event() call, which will re-sync the clock with ktime_get_ns() when TSC is unstable and no-op otherwise. Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Fixes: e93e59ce5b85 ("cpuidle: Replace ktime_get() with local_clock()") Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/clock.c')
-rw-r--r--kernel/sched/clock.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index c30c05f05d6f..d4c2f89fac92 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -410,14 +410,21 @@ void sched_clock_idle_sleep_event(void)
EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
/*
- * We just idled; resync with ktime. (called with irqs disabled):
+ * We just idled; resync with ktime.
*/
void sched_clock_idle_wakeup_event(void)
{
- if (timekeeping_suspended)
+ unsigned long flags;
+
+ if (sched_clock_stable())
+ return;
+
+ if (unlikely(timekeeping_suspended))
return;
+ local_irq_save(flags);
sched_clock_tick();
+ local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);