Messages in this thread | | | Subject | Re: [PATCH v5 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting | From | Guenter Roeck <> | Date | Fri, 18 Jan 2019 04:04:53 -0800 |
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On 1/18/19 2:42 AM, Vincent Guittot wrote: > Hi Guenter, > > Le Thursday 17 Jan 2019 à 14:16:28 (-0800), Guenter Roeck a écrit : >> On Fri, Dec 21, 2018 at 11:33:56AM +0100, Vincent Guittot wrote: >>> From: Thara Gopinath <thara.gopinath@linaro.org> >>> >>> This patch replaces jiffies based accounting for runtime_active_time >>> and runtime_suspended_time with ktime base accounting. This makes the >>> runtime debug counters inline with genpd and other pm subsytems which >>> uses ktime based accounting. >>> >>> timekeeping is initialized before pm_runtime_init() so ktime_get() will >>> be ready before first call. In fact, timekeeping_init() is called early >>> in start_kernel() which is way before driver_init() (and that's when >>> devices can start to be initialized) called from rest_init() via >>> kernel_init_freeable() and do_basic_setup(). >>> >> This is not (always) correct. My qemu "collie" boot test fails with this >> patch applied. Reverting the patch fixes the problem. Bisect log attached. >> > > Can you try the patch below ? > ktime_get_mono_fast_ns() has the advantage of being init with dummy clock so > it can be used at early_init. > Yes, that works.
Guenter
> --- > drivers/base/power/runtime.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > index ae1c728..118c7f6 100644 > --- a/drivers/base/power/runtime.c > +++ b/drivers/base/power/runtime.c > @@ -66,7 +66,7 @@ static int rpm_suspend(struct device *dev, int rpmflags); > */ > void update_pm_runtime_accounting(struct device *dev) > { > - u64 now = ktime_to_ns(ktime_get()); > + u64 now = ktime_get_mono_fast_ns(); > u64 delta; > > delta = now - dev->power.accounting_timestamp; > @@ -1507,7 +1507,7 @@ void pm_runtime_init(struct device *dev) > dev->power.request_pending = false; > dev->power.request = RPM_REQ_NONE; > dev->power.deferred_resume = false; > - dev->power.accounting_timestamp = ktime_to_ns(ktime_get()); > + dev->power.accounting_timestamp = ktime_get_mono_fast_ns(); > INIT_WORK(&dev->power.work, pm_runtime_work); > > dev->power.timer_expires = 0; >
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