diff options
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 37c0ff6c805..43a54fd6bfa 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -34,7 +34,7 @@ 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}; +enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT, MENU_HRTIMER_GENERAL}; /* * Concepts and ideas behind the menu governor @@ -116,6 +116,13 @@ enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT}; * */ +/* + * 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; @@ -216,6 +223,16 @@ EXPORT_SYMBOL_GPL(menu_hrtimer_cancel); 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; @@ -353,6 +370,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) /* 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 @@ -363,12 +381,26 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) */ timer_us = 2 * (data->predicted_us + MAX_DEVIATION); + perfect_us = perfect_cstate_ms * 1000; + if (repeat && (4 * timer_us < data->expected_us)) { 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. + */ + 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; |