* [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
@ 2018-12-20 14:17 Vincent Guittot
2018-12-20 22:02 ` Ulf Hansson
0 siblings, 1 reply; 5+ messages in thread
From: Vincent Guittot @ 2018-12-20 14:17 UTC (permalink / raw)
To: linux-pm, linux-kernel, rjw, thara.gopinath, jani.nikula,
joonas.lahtinen, rodrigo.vivi, airlied, intel-gfx, dri-devel
Cc: ulf.hansson, Vincent Guittot
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.
Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
[move from ktime to raw nsec]
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
drivers/base/power/runtime.c | 17 +++++++++--------
drivers/base/power/sysfs.c | 11 ++++++++---
include/linux/pm.h | 6 +++---
3 files changed, 20 insertions(+), 14 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index e695544..f700524 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -64,8 +64,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
*/
void update_pm_runtime_accounting(struct device *dev)
{
- unsigned long now = jiffies;
- unsigned long delta;
+ u64 now = ktime_to_ns(ktime_get());
+ u64 delta;
delta = now - dev->power.accounting_timestamp;
@@ -75,9 +75,9 @@ void update_pm_runtime_accounting(struct device *dev)
return;
if (dev->power.runtime_status == RPM_SUSPENDED)
- dev->power.suspended_jiffies += delta;
+ dev->power.suspended_time += delta;
else
- dev->power.active_jiffies += delta;
+ dev->power.active_time += delta;
}
static void __update_runtime_status(struct device *dev, enum rpm_status status)
@@ -88,17 +88,18 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
u64 pm_runtime_suspended_time(struct device *dev)
{
- unsigned long flags, time;
+ u64 time;
+ unsigned long flags;
spin_lock_irqsave(&dev->power.lock, flags);
update_pm_runtime_accounting(dev);
- time = dev->power.suspended_jiffies;
+ time = dev->power.suspended_time;
spin_unlock_irqrestore(&dev->power.lock, flags);
- return jiffies_to_nsecs(time);
+ return time;
}
EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
@@ -1503,7 +1504,7 @@ 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 = jiffies;
+ dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
INIT_WORK(&dev->power.work, pm_runtime_work);
dev->power.timer_expires = 0;
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index d713738..96c8a22 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -125,9 +125,12 @@ static ssize_t runtime_active_time_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int ret;
+ u64 tmp;
spin_lock_irq(&dev->power.lock);
update_pm_runtime_accounting(dev);
- ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
+ tmp = dev->power.active_time;
+ do_div(tmp, NSEC_PER_MSEC);
+ ret = sprintf(buf, "%llu\n", tmp);
spin_unlock_irq(&dev->power.lock);
return ret;
}
@@ -138,10 +141,12 @@ static ssize_t runtime_suspended_time_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int ret;
+ u64 tmp;
spin_lock_irq(&dev->power.lock);
update_pm_runtime_accounting(dev);
- ret = sprintf(buf, "%i\n",
- jiffies_to_msecs(dev->power.suspended_jiffies));
+ tmp = dev->power.suspended_time;
+ do_div(tmp, NSEC_PER_MSEC);
+ ret = sprintf(buf, "%llu\n", tmp);
spin_unlock_irq(&dev->power.lock);
return ret;
}
diff --git a/include/linux/pm.h b/include/linux/pm.h
index e723b78..e5a34e2 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -632,9 +632,9 @@ struct dev_pm_info {
int runtime_error;
int autosuspend_delay;
unsigned long last_busy;
- unsigned long active_jiffies;
- unsigned long suspended_jiffies;
- unsigned long accounting_timestamp;
+ u64 active_time;
+ u64 suspended_time;
+ u64 accounting_timestamp;
#endif
struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */
void (*set_latency_tolerance)(struct device *, s32);
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
2018-12-20 14:17 [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting Vincent Guittot
@ 2018-12-20 22:02 ` Ulf Hansson
2018-12-21 8:31 ` Vincent Guittot
2018-12-21 8:58 ` Rafael J. Wysocki
0 siblings, 2 replies; 5+ messages in thread
From: Ulf Hansson @ 2018-12-20 22:02 UTC (permalink / raw)
To: Vincent Guittot
Cc: dri-devel, Linux PM, David Airlie,
Intel graphics driver community testing & development,
Rafael J. Wysocki, Linux Kernel Mailing List, Thara Gopinath,
rodrigo.vivi
On Thu, 20 Dec 2018 at 15:17, Vincent Guittot
<vincent.guittot@linaro.org> 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.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> [move from ktime to raw nsec]
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> drivers/base/power/runtime.c | 17 +++++++++--------
> drivers/base/power/sysfs.c | 11 ++++++++---
> include/linux/pm.h | 6 +++---
> 3 files changed, 20 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index e695544..f700524 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -64,8 +64,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
> */
> void update_pm_runtime_accounting(struct device *dev)
> {
> - unsigned long now = jiffies;
> - unsigned long delta;
> + u64 now = ktime_to_ns(ktime_get());
> + u64 delta;
>
> delta = now - dev->power.accounting_timestamp;
>
> @@ -75,9 +75,9 @@ void update_pm_runtime_accounting(struct device *dev)
> return;
>
> if (dev->power.runtime_status == RPM_SUSPENDED)
> - dev->power.suspended_jiffies += delta;
> + dev->power.suspended_time += delta;
> else
> - dev->power.active_jiffies += delta;
> + dev->power.active_time += delta;
> }
>
> static void __update_runtime_status(struct device *dev, enum rpm_status status)
> @@ -88,17 +88,18 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
>
> u64 pm_runtime_suspended_time(struct device *dev)
> {
> - unsigned long flags, time;
> + u64 time;
> + unsigned long flags;
>
> spin_lock_irqsave(&dev->power.lock, flags);
>
> update_pm_runtime_accounting(dev);
>
> - time = dev->power.suspended_jiffies;
> + time = dev->power.suspended_time;
>
> spin_unlock_irqrestore(&dev->power.lock, flags);
>
> - return jiffies_to_nsecs(time);
> + return time;
> }
> EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
>
> @@ -1503,7 +1504,7 @@ 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 = jiffies;
> + dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
This change worries me a bit, but it may not be a problem in practice.
pm_runtime_init() is called when devices get initialized, via
device_initialize(). If timekeeping has not been initialized prior a
call to ktime_get() is done, it will fail and causing a NULL pointer
deference or something along those lines.
In other words, do we know that device_initialize() is always called
after timekeeping has been initialized during boot?
[...]
Kind regards
Uffe
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
2018-12-20 22:02 ` Ulf Hansson
@ 2018-12-21 8:31 ` Vincent Guittot
2018-12-21 8:58 ` Rafael J. Wysocki
1 sibling, 0 replies; 5+ messages in thread
From: Vincent Guittot @ 2018-12-21 8:31 UTC (permalink / raw)
To: Ulf Hansson
Cc: dri-devel, Linux PM, David Airlie,
Intel graphics driver community testing & development,
Rafael J. Wysocki, Linux Kernel Mailing List, Thara Gopinath,
rodrigo.vivi
On Thu, 20 Dec 2018 at 23:03, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Thu, 20 Dec 2018 at 15:17, Vincent Guittot
> <vincent.guittot@linaro.org> 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.
> >
> > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> > [move from ktime to raw nsec]
> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > ---
> > drivers/base/power/runtime.c | 17 +++++++++--------
> > drivers/base/power/sysfs.c | 11 ++++++++---
> > include/linux/pm.h | 6 +++---
> > 3 files changed, 20 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> > index e695544..f700524 100644
> > --- a/drivers/base/power/runtime.c
> > +++ b/drivers/base/power/runtime.c
> > @@ -64,8 +64,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
> > */
> > void update_pm_runtime_accounting(struct device *dev)
> > {
> > - unsigned long now = jiffies;
> > - unsigned long delta;
> > + u64 now = ktime_to_ns(ktime_get());
> > + u64 delta;
> >
> > delta = now - dev->power.accounting_timestamp;
> >
> > @@ -75,9 +75,9 @@ void update_pm_runtime_accounting(struct device *dev)
> > return;
> >
> > if (dev->power.runtime_status == RPM_SUSPENDED)
> > - dev->power.suspended_jiffies += delta;
> > + dev->power.suspended_time += delta;
> > else
> > - dev->power.active_jiffies += delta;
> > + dev->power.active_time += delta;
> > }
> >
> > static void __update_runtime_status(struct device *dev, enum rpm_status status)
> > @@ -88,17 +88,18 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
> >
> > u64 pm_runtime_suspended_time(struct device *dev)
> > {
> > - unsigned long flags, time;
> > + u64 time;
> > + unsigned long flags;
> >
> > spin_lock_irqsave(&dev->power.lock, flags);
> >
> > update_pm_runtime_accounting(dev);
> >
> > - time = dev->power.suspended_jiffies;
> > + time = dev->power.suspended_time;
> >
> > spin_unlock_irqrestore(&dev->power.lock, flags);
> >
> > - return jiffies_to_nsecs(time);
> > + return time;
> > }
> > EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
> >
> > @@ -1503,7 +1504,7 @@ 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 = jiffies;
> > + dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
>
> This change worries me a bit, but it may not be a problem in practice.
>
> pm_runtime_init() is called when devices get initialized, via
> device_initialize(). If timekeeping has not been initialized prior a
> call to ktime_get() is done, it will fail and causing a NULL pointer
> deference or something along those lines.
>
> In other words, do we know that device_initialize() is always called
> after timekeeping has been initialized during boot?
That something we discussed at lpc and we should be safe
>
> [...]
>
> Kind regards
> Uffe
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
2018-12-20 22:02 ` Ulf Hansson
2018-12-21 8:31 ` Vincent Guittot
@ 2018-12-21 8:58 ` Rafael J. Wysocki
2018-12-21 10:06 ` Vincent Guittot
1 sibling, 1 reply; 5+ messages in thread
From: Rafael J. Wysocki @ 2018-12-21 8:58 UTC (permalink / raw)
To: Ulf Hansson
Cc: Vincent Guittot, dri-devel, Linux PM, David Airlie, intel-gfx,
Rafael J. Wysocki, Linux Kernel Mailing List, Thara Gopinath,
rodrigo.vivi
On Thu, Dec 20, 2018 at 11:03 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Thu, 20 Dec 2018 at 15:17, Vincent Guittot
> <vincent.guittot@linaro.org> 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.
> >
> > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> > [move from ktime to raw nsec]
> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > ---
> > drivers/base/power/runtime.c | 17 +++++++++--------
> > drivers/base/power/sysfs.c | 11 ++++++++---
> > include/linux/pm.h | 6 +++---
> > 3 files changed, 20 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> > index e695544..f700524 100644
> > --- a/drivers/base/power/runtime.c
> > +++ b/drivers/base/power/runtime.c
> > @@ -64,8 +64,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
> > */
> > void update_pm_runtime_accounting(struct device *dev)
> > {
> > - unsigned long now = jiffies;
> > - unsigned long delta;
> > + u64 now = ktime_to_ns(ktime_get());
> > + u64 delta;
> >
> > delta = now - dev->power.accounting_timestamp;
> >
> > @@ -75,9 +75,9 @@ void update_pm_runtime_accounting(struct device *dev)
> > return;
> >
> > if (dev->power.runtime_status == RPM_SUSPENDED)
> > - dev->power.suspended_jiffies += delta;
> > + dev->power.suspended_time += delta;
> > else
> > - dev->power.active_jiffies += delta;
> > + dev->power.active_time += delta;
> > }
> >
> > static void __update_runtime_status(struct device *dev, enum rpm_status status)
> > @@ -88,17 +88,18 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
> >
> > u64 pm_runtime_suspended_time(struct device *dev)
> > {
> > - unsigned long flags, time;
> > + u64 time;
> > + unsigned long flags;
> >
> > spin_lock_irqsave(&dev->power.lock, flags);
> >
> > update_pm_runtime_accounting(dev);
> >
> > - time = dev->power.suspended_jiffies;
> > + time = dev->power.suspended_time;
> >
> > spin_unlock_irqrestore(&dev->power.lock, flags);
> >
> > - return jiffies_to_nsecs(time);
> > + return time;
> > }
> > EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
> >
> > @@ -1503,7 +1504,7 @@ 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 = jiffies;
> > + dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
>
> This change worries me a bit, but it may not be a problem in practice.
>
> pm_runtime_init() is called when devices get initialized, via
> device_initialize(). If timekeeping has not been initialized prior a
> call to ktime_get() is done, it will fail and causing a NULL pointer
> deference or something along those lines.
>
> In other words, do we know that device_initialize() is always called
> after timekeeping has been initialized during boot?
We do.
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().
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
2018-12-21 8:58 ` Rafael J. Wysocki
@ 2018-12-21 10:06 ` Vincent Guittot
0 siblings, 0 replies; 5+ messages in thread
From: Vincent Guittot @ 2018-12-21 10:06 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Ulf Hansson, dri-devel, Linux PM, David Airlie, intel-gfx,
Rafael J. Wysocki, Linux Kernel Mailing List, Thara Gopinath,
rodrigo.vivi
Hi Rafael,
On Fri, 21 Dec 2018 at 09:58, Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Thu, Dec 20, 2018 at 11:03 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> >
> > On Thu, 20 Dec 2018 at 15:17, Vincent Guittot
> > <vincent.guittot@linaro.org> 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.
> > >
> > > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> > > [move from ktime to raw nsec]
> > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > > ---
> > > drivers/base/power/runtime.c | 17 +++++++++--------
> > > drivers/base/power/sysfs.c | 11 ++++++++---
> > > include/linux/pm.h | 6 +++---
> > > 3 files changed, 20 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> > > index e695544..f700524 100644
> > > --- a/drivers/base/power/runtime.c
> > > +++ b/drivers/base/power/runtime.c
> > > @@ -64,8 +64,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
> > > */
> > > void update_pm_runtime_accounting(struct device *dev)
> > > {
> > > - unsigned long now = jiffies;
> > > - unsigned long delta;
> > > + u64 now = ktime_to_ns(ktime_get());
> > > + u64 delta;
> > >
> > > delta = now - dev->power.accounting_timestamp;
> > >
> > > @@ -75,9 +75,9 @@ void update_pm_runtime_accounting(struct device *dev)
> > > return;
> > >
> > > if (dev->power.runtime_status == RPM_SUSPENDED)
> > > - dev->power.suspended_jiffies += delta;
> > > + dev->power.suspended_time += delta;
> > > else
> > > - dev->power.active_jiffies += delta;
> > > + dev->power.active_time += delta;
> > > }
> > >
> > > static void __update_runtime_status(struct device *dev, enum rpm_status status)
> > > @@ -88,17 +88,18 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
> > >
> > > u64 pm_runtime_suspended_time(struct device *dev)
> > > {
> > > - unsigned long flags, time;
> > > + u64 time;
> > > + unsigned long flags;
> > >
> > > spin_lock_irqsave(&dev->power.lock, flags);
> > >
> > > update_pm_runtime_accounting(dev);
> > >
> > > - time = dev->power.suspended_jiffies;
> > > + time = dev->power.suspended_time;
> > >
> > > spin_unlock_irqrestore(&dev->power.lock, flags);
> > >
> > > - return jiffies_to_nsecs(time);
> > > + return time;
> > > }
> > > EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
> > >
> > > @@ -1503,7 +1504,7 @@ 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 = jiffies;
> > > + dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
> >
> > This change worries me a bit, but it may not be a problem in practice.
> >
> > pm_runtime_init() is called when devices get initialized, via
> > device_initialize(). If timekeeping has not been initialized prior a
> > call to ktime_get() is done, it will fail and causing a NULL pointer
> > deference or something along those lines.
> >
> > In other words, do we know that device_initialize() is always called
> > after timekeeping has been initialized during boot?
>
> We do.
>
> 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().
Thanks for the confirmation. I'm going to add your answer in the
commit message so we will have the answer next time someone will
wonder
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-12-21 10:07 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2018-12-20 14:17 [PATCH v4 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting Vincent Guittot
2018-12-20 22:02 ` Ulf Hansson
2018-12-21 8:31 ` Vincent Guittot
2018-12-21 8:58 ` Rafael J. Wysocki
2018-12-21 10:06 ` Vincent Guittot
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