On Thu, Apr 20, 2017 at 03:44:47PM +0300, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > This reverts commit e93e59ce5b85e6c2b444f09fd1f707274ec066dc. > > The TSC stops in deeper C states, On some old hardware (Core2 era and before) only. You've forgotten to mention what hardware you've observed problems with. > so using local_clock() in cpuidle But on said hardware, local_clock() isn't an immediate TSC user. > 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. Does this cure it? --- drivers/cpuidle/cpuidle.c | 2 ++ kernel/sched/clock.c | 7 +++---- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 548b90be7685..e0d4ad108887 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -219,6 +219,8 @@ 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(0); + time_end = ns_to_ktime(local_clock()); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 00a45c45beca..15e848706be4 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -347,6 +347,9 @@ void sched_clock_tick(void) { struct sched_clock_data *scd; + if (timekeeping_suspended) + return; + WARN_ON_ONCE(!irqs_disabled()); /* @@ -378,11 +381,7 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); */ void sched_clock_idle_wakeup_event(u64 delta_ns) { - if (timekeeping_suspended) - return; - sched_clock_tick(); - touch_softlockup_watchdog_sched(); } EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);