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PM / Domains: Merge measurements for PM QoS device latencies

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Measure latency does by itself contribute to an increased latency, thus we
should avoid it when it isn't needed.

By merging the latency measurements for the ->save_state() and the
->stop() callbacks, we get one measurement instead of two and we get one
value to store instead of two. Let's also apply the likewise change for
the ->start() and ->restore_state() callbacks.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Ulf Hansson 2015-10-15 17:02:19 +02:00 committed by Rafael J. Wysocki
parent 51cda84489
commit 2b1d88cda3
3 changed files with 55 additions and 56 deletions
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99
drivers/base/power/domain.c
View File

@ -34,22 +34,6 @@
__ret; \
})
#define GENPD_DEV_TIMED_CALLBACK(genpd, type, callback, dev, field, name) \
({ \
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 gpd_timing_data *__td = &dev_gpd_data(dev)->td; \
if (!__retval && __elapsed > __td->field) { \
__td->field = __elapsed; \
dev_dbg(dev, name " latency exceeded, new value %lld ns\n", \
__elapsed); \
genpd->max_off_time_changed = true; \
__td->constraint_changed = true; \
} \
__retval; \
})
static LIST_HEAD(gpd_list);
static DEFINE_MUTEX(gpd_list_lock);
@ -90,24 +74,14 @@ static struct generic_pm_domain *dev_to_genpd(struct device *dev)
return pd_to_genpd(dev->pm_domain);
}
static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev,
bool timed)
static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
{
if (!timed)
return GENPD_DEV_CALLBACK(genpd, int, stop, dev);
return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
stop_latency_ns, "stop");
return GENPD_DEV_CALLBACK(genpd, int, stop, dev);
}
static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev,
bool timed)
static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev)
{
if (!timed)
return GENPD_DEV_CALLBACK(genpd, int, start, dev);
return GENPD_DEV_TIMED_CALLBACK(genpd, int, start, dev,
start_latency_ns, "start");
return GENPD_DEV_CALLBACK(genpd, int, start, dev);
}
static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)
@ -263,19 +237,13 @@ static int genpd_poweron(struct generic_pm_domain *genpd)
static int genpd_save_dev(struct generic_pm_domain *genpd, struct device *dev)
{
return GENPD_DEV_TIMED_CALLBACK(genpd, int, save_state, dev,
save_state_latency_ns, "state save");
return GENPD_DEV_CALLBACK(genpd, int, save_state, dev);
}
static int genpd_restore_dev(struct generic_pm_domain *genpd,
struct device *dev, bool timed)
struct device *dev)
{
if (!timed)
return GENPD_DEV_CALLBACK(genpd, int, restore_state, dev);
return GENPD_DEV_TIMED_CALLBACK(genpd, int, restore_state, dev,
restore_state_latency_ns,
"state restore");
return GENPD_DEV_CALLBACK(genpd, int, restore_state, dev);
}
static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
@ -422,6 +390,9 @@ static int pm_genpd_runtime_suspend(struct device *dev)
{
struct generic_pm_domain *genpd;
bool (*stop_ok)(struct device *__dev);
struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
ktime_t time_start;
s64 elapsed_ns;
int ret;
dev_dbg(dev, "%s()\n", __func__);
@ -434,16 +405,29 @@ static int pm_genpd_runtime_suspend(struct device *dev)
if (stop_ok && !stop_ok(dev))
return -EBUSY;
/* Measure suspend latency. */
time_start = ktime_get();
ret = genpd_save_dev(genpd, dev);
if (ret)
return ret;
ret = genpd_stop_dev(genpd, dev, true);
ret = genpd_stop_dev(genpd, dev);
if (ret) {
genpd_restore_dev(genpd, dev, true);
genpd_restore_dev(genpd, dev);
return ret;
}
/* Update suspend latency value if the measured time exceeds it. */
elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
if (elapsed_ns > td->suspend_latency_ns) {
td->suspend_latency_ns = elapsed_ns;
dev_dbg(dev, "suspend latency exceeded, %lld ns\n",
elapsed_ns);
genpd->max_off_time_changed = true;
td->constraint_changed = true;
}
/*
* If power.irq_safe is set, this routine will be run with interrupts
* off, so it can't use mutexes.
@ -469,6 +453,9 @@ static int pm_genpd_runtime_suspend(struct device *dev)
static int pm_genpd_runtime_resume(struct device *dev)
{
struct generic_pm_domain *genpd;
struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
ktime_t time_start;
s64 elapsed_ns;
int ret;
bool timed = true;
@ -492,8 +479,24 @@ static int pm_genpd_runtime_resume(struct device *dev)
return ret;
out:
genpd_start_dev(genpd, dev, timed);
genpd_restore_dev(genpd, dev, timed);
/* Measure resume latency. */
if (timed)
time_start = ktime_get();
genpd_start_dev(genpd, dev);
genpd_restore_dev(genpd, dev);
/* Update resume latency value if the measured time exceeds it. */
if (timed) {
elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start));
if (elapsed_ns > td->resume_latency_ns) {
td->resume_latency_ns = elapsed_ns;
dev_dbg(dev, "resume latency exceeded, %lld ns\n",
elapsed_ns);
genpd->max_off_time_changed = true;
td->constraint_changed = true;
}
}
return 0;
}
@ -783,7 +786,7 @@ static int pm_genpd_suspend_noirq(struct device *dev)
|| (dev->power.wakeup_path && genpd_dev_active_wakeup(genpd, dev)))
return 0;
genpd_stop_dev(genpd, dev, false);
genpd_stop_dev(genpd, dev);
/*
* Since all of the "noirq" callbacks are executed sequentially, it is
@ -824,7 +827,7 @@ static int pm_genpd_resume_noirq(struct device *dev)
pm_genpd_sync_poweron(genpd, true);
genpd->suspended_count--;
return genpd_start_dev(genpd, dev, false);
return genpd_start_dev(genpd, dev);
}
/**
@ -932,7 +935,7 @@ static int pm_genpd_freeze_noirq(struct device *dev)
if (IS_ERR(genpd))
return -EINVAL;
return genpd->suspend_power_off ? 0 : genpd_stop_dev(genpd, dev, false);
return genpd->suspend_power_off ? 0 : genpd_stop_dev(genpd, dev);
}
/**
@ -953,7 +956,7 @@ static int pm_genpd_thaw_noirq(struct device *dev)
return -EINVAL;
return genpd->suspend_power_off ?
0 : genpd_start_dev(genpd, dev, false);
0 : genpd_start_dev(genpd, dev);
}
/**
@ -1047,7 +1050,7 @@ static int pm_genpd_restore_noirq(struct device *dev)
pm_genpd_sync_poweron(genpd, true);
return genpd_start_dev(genpd, dev, false);
return genpd_start_dev(genpd, dev);
}
/**

6
drivers/base/power/domain_governor.c
View File

@ -77,10 +77,8 @@ static bool default_stop_ok(struct device *dev)
dev_update_qos_constraint);
if (constraint_ns > 0) {
constraint_ns -= td->save_state_latency_ns +
td->stop_latency_ns +
td->start_latency_ns +
td->restore_state_latency_ns;
constraint_ns -= td->suspend_latency_ns +
td->resume_latency_ns;
if (constraint_ns == 0)
return false;
}

6
include/linux/pm_domain.h
View File

@ -81,10 +81,8 @@ struct gpd_link {
};
struct gpd_timing_data {
s64 stop_latency_ns;
s64 start_latency_ns;
s64 save_state_latency_ns;
s64 restore_state_latency_ns;
s64 suspend_latency_ns;
s64 resume_latency_ns;
s64 effective_constraint_ns;
bool constraint_changed;
bool cached_stop_ok;