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Merge branch 'pm-cpuidle'

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* pm-cpuidle:
  cpuidle: delay enabling interrupts until all coupled CPUs leave idle
  cpuidle: poll state can measure residency
  cpuidle: Move perf multiplier calculation out of the selection loop
  cpuidle: Do not substract exit latency from assumed sleep length
  cpuidle: Ensure menu coefficients stay within domain
  cpuidle: Use actual state latency in menu governor
  cpuidle: rename expected_us to next_timer_us in menu governor
This commit is contained in:
Rafael J. Wysocki 2014-03-20 13:26:05 +01:00
commit f71a822fc0
3 changed files with 47 additions and 33 deletions
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3
drivers/cpuidle/cpuidle.c
View File

@ -85,7 +85,8 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
time_end = ktime_get();
local_irq_enable();
if (!cpuidle_state_is_coupled(dev, drv, entered_state))
local_irq_enable();
diff = ktime_to_us(ktime_sub(time_end, time_start));
if (diff > INT_MAX)

2
drivers/cpuidle/driver.c
View File

@ -209,7 +209,7 @@ static void poll_idle_init(struct cpuidle_driver *drv)
state->exit_latency = 0;
state->target_residency = 0;
state->power_usage = -1;
state->flags = 0;
state->flags = CPUIDLE_FLAG_TIME_VALID;
state->enter = poll_idle;
state->disabled = false;
}

75
drivers/cpuidle/governors/menu.c
View File

@ -122,9 +122,8 @@ struct menu_device {
int last_state_idx;
int needs_update;
unsigned int expected_us;
unsigned int next_timer_us;
unsigned int predicted_us;
unsigned int exit_us;
unsigned int bucket;
unsigned int correction_factor[BUCKETS];
unsigned int intervals[INTERVALS];
@ -257,7 +256,7 @@ again:
stddev = int_sqrt(stddev);
if (((avg > stddev * 6) && (divisor * 4 >= INTERVALS * 3))
|| stddev <= 20) {
if (data->expected_us > avg)
if (data->next_timer_us > avg)
data->predicted_us = avg;
return;
}
@ -289,7 +288,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
struct menu_device *data = &__get_cpu_var(menu_devices);
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
int i;
int multiplier;
unsigned int interactivity_req;
struct timespec t;
if (data->needs_update) {
@ -298,7 +297,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
}
data->last_state_idx = 0;
data->exit_us = 0;
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0))
@ -306,13 +304,11 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
/* determine the expected residency time, round up */
t = ktime_to_timespec(tick_nohz_get_sleep_length());
data->expected_us =
data->next_timer_us =
t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
data->bucket = which_bucket(data->expected_us);
multiplier = performance_multiplier();
data->bucket = which_bucket(data->next_timer_us);
/*
* if the correction factor is 0 (eg first time init or cpu hotplug
@ -326,17 +322,26 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* operands are 32 bits.
* Make sure to round up for half microseconds.
*/
data->predicted_us = div_round64((uint64_t)data->expected_us *
data->predicted_us = div_round64((uint64_t)data->next_timer_us *
data->correction_factor[data->bucket],
RESOLUTION * DECAY);
get_typical_interval(data);
/*
* Performance multiplier defines a minimum predicted idle
* duration / latency ratio. Adjust the latency limit if
* necessary.
*/
interactivity_req = data->predicted_us / performance_multiplier();
if (latency_req > interactivity_req)
latency_req = interactivity_req;
/*
* We want to default to C1 (hlt), not to busy polling
* unless the timer is happening really really soon.
*/
if (data->expected_us > 5 &&
if (data->next_timer_us > 5 &&
!drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
@ -355,11 +360,8 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
continue;
if (s->exit_latency > latency_req)
continue;
if (s->exit_latency * multiplier > data->predicted_us)
continue;
data->last_state_idx = i;
data->exit_us = s->exit_latency;
}
return data->last_state_idx;
@ -390,36 +392,47 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
int last_idx = data->last_state_idx;
unsigned int last_idle_us = cpuidle_get_last_residency(dev);
struct cpuidle_state *target = &drv->states[last_idx];
unsigned int measured_us;
unsigned int new_factor;
/*
* Ugh, this idle state doesn't support residency measurements, so we
* are basically lost in the dark. As a compromise, assume we slept
* for the whole expected time.
* Try to figure out how much time passed between entry to low
* power state and occurrence of the wakeup event.
*
* If the entered idle state didn't support residency measurements,
* we are basically lost in the dark how much time passed.
* As a compromise, assume we slept for the whole expected time.
*
* Any measured amount of time will include the exit latency.
* Since we are interested in when the wakeup begun, not when it
* was completed, we must substract the exit latency. However, if
* the measured amount of time is less than the exit latency,
* assume the state was never reached and the exit latency is 0.
*/
if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID)))
last_idle_us = data->expected_us;
if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) {
/* Use timer value as is */
measured_us = data->next_timer_us;
} else {
/* Use measured value */
measured_us = cpuidle_get_last_residency(dev);
measured_us = last_idle_us;
/*
* We correct for the exit latency; we are assuming here that the
* exit latency happens after the event that we're interested in.
*/
if (measured_us > data->exit_us)
measured_us -= data->exit_us;
/* Deduct exit latency */
if (measured_us > target->exit_latency)
measured_us -= target->exit_latency;
/* Make sure our coefficients do not exceed unity */
if (measured_us > data->next_timer_us)
measured_us = data->next_timer_us;
}
/* Update our correction ratio */
new_factor = data->correction_factor[data->bucket];
new_factor -= new_factor / DECAY;
if (data->expected_us > 0 && measured_us < MAX_INTERESTING)
new_factor += RESOLUTION * measured_us / data->expected_us;
if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING)
new_factor += RESOLUTION * measured_us / data->next_timer_us;
else
/*
* we were idle so long that we count it as a perfect
@ -439,7 +452,7 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
data->correction_factor[data->bucket] = new_factor;
/* update the repeating-pattern data */
data->intervals[data->interval_ptr++] = last_idle_us;
data->intervals[data->interval_ptr++] = measured_us;
if (data->interval_ptr >= INTERVALS)
data->interval_ptr = 0;
}