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authorPeter Zijlstra <peterz@infradead.org>2017-04-21 12:43:59 +0200
committerIngo Molnar <mingo@kernel.org>2017-05-15 10:15:20 +0200
commitf9fccdb9efef60dbcf84d493514b475c41aa866f (patch)
tree3d5278febf2aa2f0d8d2e05977c59bcd97fce350 /drivers/cpuidle
parent3067a33d5fec856bb297d58e7f03411d060ccdee (diff)
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 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 2706be7ed334..60bb64f4329d 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -220,6 +220,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
entered_state = target_state->enter(dev, drv, index);
start_critical_timings();
+ sched_clock_idle_wakeup_event();
time_end = ns_to_ktime(local_clock());
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);