#define MAX_INTERESTING 50000
#define STDDEV_THRESH 400
-/* 60 * 60 > STDDEV_THRESH * INTERVALS = 400 * 8 */
-#define MAX_DEVIATION 60
-
-static DEFINE_PER_CPU(struct hrtimer, menu_hrtimer);
-static DEFINE_PER_CPU(int, hrtimer_status);
-/* menu hrtimer mode */
-enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT, MENU_HRTIMER_GENERAL};
/*
* Concepts and ideas behind the menu governor
*
*/
-/*
- * The C-state residency is so long that is is worthwhile to exit
- * from the shallow C-state and re-enter into a deeper C-state.
- */
-static unsigned int perfect_cstate_ms __read_mostly = 30;
-module_param(perfect_cstate_ms, uint, 0000);
-
struct menu_device {
int last_state_idx;
int needs_update;
return div_u64(dividend + (divisor / 2), divisor);
}
-/* Cancel the hrtimer if it is not triggered yet */
-void menu_hrtimer_cancel(void)
-{
- int cpu = smp_processor_id();
- struct hrtimer *hrtmr = &per_cpu(menu_hrtimer, cpu);
-
- /* The timer is still not time out*/
- if (per_cpu(hrtimer_status, cpu)) {
- hrtimer_cancel(hrtmr);
- per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_STOP;
- }
-}
-EXPORT_SYMBOL_GPL(menu_hrtimer_cancel);
-
-/* Call back for hrtimer is triggered */
-static enum hrtimer_restart menu_hrtimer_notify(struct hrtimer *hrtimer)
-{
- int cpu = smp_processor_id();
- struct menu_device *data = &per_cpu(menu_devices, cpu);
-
- /* In general case, the expected residency is much larger than
- * deepest C-state target residency, but prediction logic still
- * predicts a small predicted residency, so the prediction
- * history is totally broken if the timer is triggered.
- * So reset the correction factor.
- */
- if (per_cpu(hrtimer_status, cpu) == MENU_HRTIMER_GENERAL)
- data->correction_factor[data->bucket] = RESOLUTION * DECAY;
-
- per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_STOP;
-
- return HRTIMER_NORESTART;
-}
-
/*
* Try detecting repeating patterns by keeping track of the last 8
* intervals, and checking if the standard deviation of that set
* of points is below a threshold. If it is... then use the
* average of these 8 points as the estimated value.
*/
-static u32 get_typical_interval(struct menu_device *data)
+static void get_typical_interval(struct menu_device *data)
{
int i = 0, divisor = 0;
uint64_t max = 0, avg = 0, stddev = 0;
int64_t thresh = LLONG_MAX; /* Discard outliers above this value. */
- unsigned int ret = 0;
again:
if (((avg > stddev * 6) && (divisor * 4 >= INTERVALS * 3))
|| stddev <= 20) {
data->predicted_us = avg;
- ret = 1;
- return ret;
+ return;
} else if ((divisor * 4) > INTERVALS * 3) {
/* Exclude the max interval */
thresh = max - 1;
goto again;
}
-
- return ret;
}
/**
int i;
int multiplier;
struct timespec t;
- int repeat = 0, low_predicted = 0;
- int cpu = smp_processor_id();
- struct hrtimer *hrtmr = &per_cpu(menu_hrtimer, cpu);
if (data->needs_update) {
menu_update(drv, dev);
data->predicted_us = div_round64(data->expected_us * data->correction_factor[data->bucket],
RESOLUTION * DECAY);
- repeat = get_typical_interval(data);
+ get_typical_interval(data);
/*
* We want to default to C1 (hlt), not to busy polling
if (s->disabled || su->disable)
continue;
- if (s->target_residency > data->predicted_us) {
- low_predicted = 1;
+ if (s->target_residency > data->predicted_us)
continue;
- }
if (s->exit_latency > latency_req)
continue;
if (s->exit_latency * multiplier > data->predicted_us)
data->exit_us = s->exit_latency;
}
- /* not deepest C-state chosen for low predicted residency */
- if (low_predicted) {
- unsigned int timer_us = 0;
- unsigned int perfect_us = 0;
-
- /*
- * Set a timer to detect whether this sleep is much
- * longer than repeat mode predicted. If the timer
- * triggers, the code will evaluate whether to put
- * the CPU into a deeper C-state.
- * The timer is cancelled on CPU wakeup.
- */
- timer_us = 2 * (data->predicted_us + MAX_DEVIATION);
-
- perfect_us = perfect_cstate_ms * 1000;
-
- if (repeat && (4 * timer_us < data->expected_us)) {
- RCU_NONIDLE(hrtimer_start(hrtmr,
- ns_to_ktime(1000 * timer_us),
- HRTIMER_MODE_REL_PINNED));
- /* In repeat case, menu hrtimer is started */
- per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_REPEAT;
- } else if (perfect_us < data->expected_us) {
- /*
- * The next timer is long. This could be because
- * we did not make a useful prediction.
- * In that case, it makes sense to re-enter
- * into a deeper C-state after some time.
- */
- RCU_NONIDLE(hrtimer_start(hrtmr,
- ns_to_ktime(1000 * timer_us),
- HRTIMER_MODE_REL_PINNED));
- /* In general case, menu hrtimer is started */
- per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_GENERAL;
- }
-
- }
-
return data->last_state_idx;
}
struct cpuidle_device *dev)
{
struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
- struct hrtimer *t = &per_cpu(menu_hrtimer, dev->cpu);
- hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- t->function = menu_hrtimer_notify;
memset(data, 0, sizeof(struct menu_device));
projects / firefly-linux-kernel-4.4.55.git / blobdiff