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Subject[PATCH v5 3/3] PM/runtime:Replace jiffies based accounting with ktime based accounting
Date
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().

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
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