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PM / Sleep: Change wakeup source statistics to follow Android
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Wakeup statistics used by Android are slightly different from what we
have in wakeup sources at the moment and there aren't any known
users of those statistics other than Android, so modify them to make
it easier for Android to switch to wakeup sources.

This removes the struct wakeup_source's hit_cout field, which is very
rough and therefore not very useful, and adds two new fields,
wakeup_count and expire_count.  The first one tracks how many times
the wakeup source is activated with events_check_enabled set (which
roughly corresponds to the situations when a system power transition
to a sleep state is in progress and would be aborted by this wakeup
source if it were the only active one at that time) and the second
one is the number of times the wakeup source has been activated with
a timeout that expired.

Additionally, the last_time field is now updated when the wakeup
source is deactivated too (previously it was only updated during
the wakeup source's activation), which seems to be what Android does
with the analogous counter for wakelocks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Rafael J. Wysocki committed May 1, 2012
1 parent 60af106 commit 30e3ce6
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Showing 4 changed files with 77 additions and 52 deletions.
24 changes: 17 additions & 7 deletions Documentation/ABI/testing/sysfs-devices-power
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Original file line number Diff line number Diff line change
Expand Up @@ -96,16 +96,26 @@ Description:
is read-only. If the device is not enabled to wake up the
system from sleep states, this attribute is not present.

What: /sys/devices/.../power/wakeup_hit_count
Date: September 2010
What: /sys/devices/.../power/wakeup_abort_count
Date: February 2012
Contact: Rafael J. Wysocki <rjw@sisk.pl>
Description:
The /sys/devices/.../wakeup_hit_count attribute contains the
The /sys/devices/.../wakeup_abort_count attribute contains the
number of times the processing of a wakeup event associated with
the device might prevent the system from entering a sleep state.
This attribute is read-only. If the device is not enabled to
wake up the system from sleep states, this attribute is not
present.
the device might have aborted system transition into a sleep
state in progress. This attribute is read-only. If the device
is not enabled to wake up the system from sleep states, this
attribute is not present.

What: /sys/devices/.../power/wakeup_expire_count
Date: February 2012
Contact: Rafael J. Wysocki <rjw@sisk.pl>
Description:
The /sys/devices/.../wakeup_expire_count attribute contains the
number of times a wakeup event associated with the device has
been reported with a timeout that expired. This attribute is
read-only. If the device is not enabled to wake up the system
from sleep states, this attribute is not present.

What: /sys/devices/.../power/wakeup_active
Date: September 2010
Expand Down
30 changes: 25 additions & 5 deletions drivers/base/power/sysfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -314,22 +314,41 @@ static ssize_t wakeup_active_count_show(struct device *dev,

static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);

static ssize_t wakeup_hit_count_show(struct device *dev,
struct device_attribute *attr, char *buf)
static ssize_t wakeup_abort_count_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
unsigned long count = 0;
bool enabled = false;

spin_lock_irq(&dev->power.lock);
if (dev->power.wakeup) {
count = dev->power.wakeup->wakeup_count;
enabled = true;
}
spin_unlock_irq(&dev->power.lock);
return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_abort_count, 0444, wakeup_abort_count_show, NULL);

static ssize_t wakeup_expire_count_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
unsigned long count = 0;
bool enabled = false;

spin_lock_irq(&dev->power.lock);
if (dev->power.wakeup) {
count = dev->power.wakeup->hit_count;
count = dev->power.wakeup->expire_count;
enabled = true;
}
spin_unlock_irq(&dev->power.lock);
return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_hit_count, 0444, wakeup_hit_count_show, NULL);
static DEVICE_ATTR(wakeup_expire_count, 0444, wakeup_expire_count_show, NULL);

static ssize_t wakeup_active_show(struct device *dev,
struct device_attribute *attr, char *buf)
Expand Down Expand Up @@ -486,7 +505,8 @@ static struct attribute *wakeup_attrs[] = {
&dev_attr_wakeup.attr,
&dev_attr_wakeup_count.attr,
&dev_attr_wakeup_active_count.attr,
&dev_attr_wakeup_hit_count.attr,
&dev_attr_wakeup_abort_count.attr,
&dev_attr_wakeup_expire_count.attr,
&dev_attr_wakeup_active.attr,
&dev_attr_wakeup_total_time_ms.attr,
&dev_attr_wakeup_max_time_ms.attr,
Expand Down
64 changes: 28 additions & 36 deletions drivers/base/power/wakeup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@
* If set, the suspend/hibernate code will abort transitions to a sleep state
* if wakeup events are registered during or immediately before the transition.
*/
bool events_check_enabled;
bool events_check_enabled __read_mostly;

/*
* Combined counters of registered wakeup events and wakeup events in progress.
Expand Down Expand Up @@ -382,6 +382,21 @@ static void wakeup_source_activate(struct wakeup_source *ws)
atomic_inc(&combined_event_count);
}

/**
* wakeup_source_report_event - Report wakeup event using the given source.
* @ws: Wakeup source to report the event for.
*/
static void wakeup_source_report_event(struct wakeup_source *ws)
{
ws->event_count++;
/* This is racy, but the counter is approximate anyway. */
if (events_check_enabled)
ws->wakeup_count++;

if (!ws->active)
wakeup_source_activate(ws);
}

/**
* __pm_stay_awake - Notify the PM core of a wakeup event.
* @ws: Wakeup source object associated with the source of the event.
Expand All @@ -397,10 +412,7 @@ void __pm_stay_awake(struct wakeup_source *ws)

spin_lock_irqsave(&ws->lock, flags);

ws->event_count++;
if (!ws->active)
wakeup_source_activate(ws);

wakeup_source_report_event(ws);
del_timer(&ws->timer);
ws->timer_expires = 0;

Expand Down Expand Up @@ -469,6 +481,7 @@ static void wakeup_source_deactivate(struct wakeup_source *ws)
if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
ws->max_time = duration;

ws->last_time = now;
del_timer(&ws->timer);
ws->timer_expires = 0;

Expand Down Expand Up @@ -541,8 +554,10 @@ static void pm_wakeup_timer_fn(unsigned long data)
spin_lock_irqsave(&ws->lock, flags);

if (ws->active && ws->timer_expires
&& time_after_eq(jiffies, ws->timer_expires))
&& time_after_eq(jiffies, ws->timer_expires)) {
wakeup_source_deactivate(ws);
ws->expire_count++;
}

spin_unlock_irqrestore(&ws->lock, flags);
}
Expand All @@ -569,9 +584,7 @@ void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)

spin_lock_irqsave(&ws->lock, flags);

ws->event_count++;
if (!ws->active)
wakeup_source_activate(ws);
wakeup_source_report_event(ws);

if (!msec) {
wakeup_source_deactivate(ws);
Expand Down Expand Up @@ -613,24 +626,6 @@ void pm_wakeup_event(struct device *dev, unsigned int msec)
}
EXPORT_SYMBOL_GPL(pm_wakeup_event);

/**
* pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
*/
static void pm_wakeup_update_hit_counts(void)
{
unsigned long flags;
struct wakeup_source *ws;

rcu_read_lock();
list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
spin_lock_irqsave(&ws->lock, flags);
if (ws->active)
ws->hit_count++;
spin_unlock_irqrestore(&ws->lock, flags);
}
rcu_read_unlock();
}

/**
* pm_wakeup_pending - Check if power transition in progress should be aborted.
*
Expand All @@ -653,8 +648,6 @@ bool pm_wakeup_pending(void)
events_check_enabled = !ret;
}
spin_unlock_irqrestore(&events_lock, flags);
if (ret)
pm_wakeup_update_hit_counts();
return ret;
}

Expand All @@ -680,7 +673,6 @@ bool pm_get_wakeup_count(unsigned int *count)
split_counters(&cnt, &inpr);
if (inpr == 0 || signal_pending(current))
break;
pm_wakeup_update_hit_counts();

schedule();
}
Expand Down Expand Up @@ -713,8 +705,6 @@ bool pm_save_wakeup_count(unsigned int count)
events_check_enabled = true;
}
spin_unlock_irq(&events_lock);
if (!events_check_enabled)
pm_wakeup_update_hit_counts();
return events_check_enabled;
}

Expand Down Expand Up @@ -749,9 +739,10 @@ static int print_wakeup_source_stats(struct seq_file *m,
active_time = ktime_set(0, 0);
}

ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t"
ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t"
"%lld\t\t%lld\t\t%lld\t\t%lld\n",
ws->name, active_count, ws->event_count, ws->hit_count,
ws->name, active_count, ws->event_count,
ws->wakeup_count, ws->expire_count,
ktime_to_ms(active_time), ktime_to_ms(total_time),
ktime_to_ms(max_time), ktime_to_ms(ws->last_time));

Expand All @@ -768,8 +759,9 @@ static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
{
struct wakeup_source *ws;

seq_puts(m, "name\t\tactive_count\tevent_count\thit_count\t"
"active_since\ttotal_time\tmax_time\tlast_change\n");
seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
"expire_count\tactive_since\ttotal_time\tmax_time\t"
"last_change\n");

rcu_read_lock();
list_for_each_entry_rcu(ws, &wakeup_sources, entry)
Expand Down
11 changes: 7 additions & 4 deletions include/linux/pm_wakeup.h
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Original file line number Diff line number Diff line change
Expand Up @@ -33,12 +33,14 @@
*
* @total_time: Total time this wakeup source has been active.
* @max_time: Maximum time this wakeup source has been continuously active.
* @last_time: Monotonic clock when the wakeup source's was activated last time.
* @last_time: Monotonic clock when the wakeup source's was touched last time.
* @event_count: Number of signaled wakeup events.
* @active_count: Number of times the wakeup sorce was activated.
* @relax_count: Number of times the wakeup sorce was deactivated.
* @hit_count: Number of times the wakeup sorce might abort system suspend.
* @expire_count: Number of times the wakeup source's timeout has expired.
* @wakeup_count: Number of times the wakeup source might abort suspend.
* @active: Status of the wakeup source.
* @has_timeout: The wakeup source has been activated with a timeout.
*/
struct wakeup_source {
const char *name;
Expand All @@ -52,8 +54,9 @@ struct wakeup_source {
unsigned long event_count;
unsigned long active_count;
unsigned long relax_count;
unsigned long hit_count;
unsigned int active:1;
unsigned long expire_count;
unsigned long wakeup_count;
bool active:1;
};

#ifdef CONFIG_PM_SLEEP
Expand Down

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