[PATCH 7/7] PM / Domains: Automatically update overoptimistic latency information

Rafael J. Wysocki
2011-11-07T00:08:47Z

Measure the time of execution of the .start(), .save_state()
and .restore_state() PM domain device callbacks and if the result
is greater than the corresponding latency value stored in the
device's struct generic_pm_domain_data object, replace the inaccurate
value with the measured time.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/base/power/domain.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

Index: linux/drivers/base/power/domain.c
===================================================================
--- linux.orig/drivers/base/power/domain.c
+++ linux/drivers/base/power/domain.c
@@ -32,6 +32,17 @@
__ret; \
})

+#define GENPD_DEV_TIMED_CALLBACK(genpd, type, callback, dev, latency) \
+({ \
+ ktime_t __start = ktime_get(); \
+ type __retval = GENPD_DEV_CALLBACK(genpd, type, callback, dev); \
+ s64 __elapsed = ktime_to_ns(ktime_sub(ktime_get(), __start)); \
+ struct generic_pm_domain_data *__gpd_data = dev_gpd_data(dev); \
+ if (__elapsed > __gpd_data->td.latency) \
+ __gpd_data->td.latency = __elapsed; \
+ __retval; \
+})
+
static LIST_HEAD(gpd_list);
static DEFINE_MUTEX(gpd_list_lock);

@@ -53,17 +64,20 @@ static int genpd_stop_dev(struct generic

static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev)
{
- return GENPD_DEV_CALLBACK(genpd, int, start, dev);
+ return GENPD_DEV_TIMED_CALLBACK(genpd, int, start, dev,
+ start_latency_ns);
}

static int genpd_save_dev(struct generic_pm_domain *genpd, struct device *dev)
{
- return GENPD_DEV_CALLBACK(genpd, int, save_state, dev);
+ return GENPD_DEV_TIMED_CALLBACK(genpd, int, save_state, dev,
+ save_state_latency_ns);
}

static int genpd_restore_dev(struct generic_pm_domain *genpd, struct device *dev)
{
- return GENPD_DEV_CALLBACK(genpd, int, restore_state, dev);
+ return GENPD_DEV_TIMED_CALLBACK(genpd, int, restore_state, dev,
+ restore_state_latency_ns);
}

static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)