From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> This reverts commit e93e59ce5b85e6c2b444f09fd1f707274ec066dc. The TSC stops in deeper C states, so using local_clock() in cpuidle to track the C state residency seems like a bad idea. With local_clock() powertop is reporting mostly 0% residency for C states here. Presumably the core is still spending most of its time in some deep C-state since the totals typically add up to only 5% or so, so perhaps the governor isn't getting totally confused by these bogus numbers. But let's go back to using ktime_get() as that at least works correctly across the board. Note that the code has changed somewhat since the regression happened, so this isn't a 1:1 revert of the offending commit. Cc: stable@xxxxxxxxxxxxxxx Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/cpuidle/cpuidle.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 548b90be7685..24a52805527f 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -213,13 +213,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, sched_idle_set_state(target_state); trace_cpu_idle_rcuidle(index, dev->cpu); - time_start = ns_to_ktime(local_clock()); + time_start = ktime_get(); stop_critical_timings(); entered_state = target_state->enter(dev, drv, index); start_critical_timings(); - time_end = ns_to_ktime(local_clock()); + time_end = ktime_get(); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); /* The cpu is no longer idle or about to enter idle. */ -- 2.10.2