lkml.org 
[lkml]   [2019]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v5 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
From
Date
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;
>

\
 
 \ /
  Last update: 2019-01-18 13:05    [W:0.109 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site