diff options
Diffstat (limited to 'drivers/cpuidle/governors/menu.c')
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 120 |
1 files changed, 65 insertions, 55 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 52d5d26fc7c6..4d9aa5ce31f0 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -97,6 +97,14 @@ static inline int which_bucket(u64 duration_ns) static DEFINE_PER_CPU(struct menu_device, menu_devices); +static void menu_update_intervals(struct menu_device *data, unsigned int interval_us) +{ + /* Update the repeating-pattern data. */ + data->intervals[data->interval_ptr++] = interval_us; + if (data->interval_ptr >= INTERVALS) + data->interval_ptr = 0; +} + static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev); /* @@ -222,6 +230,14 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, if (data->needs_update) { menu_update(drv, dev); data->needs_update = 0; + } else if (!dev->last_residency_ns) { + /* + * This happens when the driver rejects the previously selected + * idle state and returns an error, so update the recent + * intervals table to prevent invalid information from being + * used going forward. + */ + menu_update_intervals(data, UINT_MAX); } /* Find the shortest expected idle interval. */ @@ -271,20 +287,15 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, return 0; } - if (tick_nohz_tick_stopped()) { - /* - * If the tick is already stopped, the cost of possible short - * idle duration misprediction is much higher, because the CPU - * may be stuck in a shallow idle state for a long time as a - * result of it. In that case say we might mispredict and use - * the known time till the closest timer event for the idle - * state selection. - */ - if (predicted_ns < TICK_NSEC) - predicted_ns = data->next_timer_ns; - } else if (latency_req > predicted_ns) { - latency_req = predicted_ns; - } + /* + * If the tick is already stopped, the cost of possible short idle + * duration misprediction is much higher, because the CPU may be stuck + * in a shallow idle state for a long time as a result of it. In that + * case, say we might mispredict and use the known time till the closest + * timer event for the idle state selection. + */ + if (tick_nohz_tick_stopped() && predicted_ns < TICK_NSEC) + predicted_ns = data->next_timer_ns; /* * Find the idle state with the lowest power while satisfying @@ -300,48 +311,50 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, if (idx == -1) idx = i; /* first enabled state */ - if (s->target_residency_ns > predicted_ns) { - /* - * Use a physical idle state, not busy polling, unless - * a timer is going to trigger soon enough. - */ - if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) && - s->exit_latency_ns <= latency_req && - s->target_residency_ns <= data->next_timer_ns) { - predicted_ns = s->target_residency_ns; - idx = i; - break; - } - if (predicted_ns < TICK_NSEC) - break; - - if (!tick_nohz_tick_stopped()) { - /* - * If the state selected so far is shallow, - * waking up early won't hurt, so retain the - * tick in that case and let the governor run - * again in the next iteration of the loop. - */ - predicted_ns = drv->states[idx].target_residency_ns; - break; - } + if (s->exit_latency_ns > latency_req) + break; - /* - * If the state selected so far is shallow and this - * state's target residency matches the time till the - * closest timer event, select this one to avoid getting - * stuck in the shallow one for too long. - */ - if (drv->states[idx].target_residency_ns < TICK_NSEC && - s->target_residency_ns <= delta_tick) - idx = i; + if (s->target_residency_ns <= predicted_ns) { + idx = i; + continue; + } - return idx; + /* + * Use a physical idle state, not busy polling, unless a timer + * is going to trigger soon enough. + */ + if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) && + s->target_residency_ns <= data->next_timer_ns) { + predicted_ns = s->target_residency_ns; + idx = i; + break; } - if (s->exit_latency_ns > latency_req) + + if (predicted_ns < TICK_NSEC) break; - idx = i; + if (!tick_nohz_tick_stopped()) { + /* + * If the state selected so far is shallow, waking up + * early won't hurt, so retain the tick in that case and + * let the governor run again in the next iteration of + * the idle loop. + */ + predicted_ns = drv->states[idx].target_residency_ns; + break; + } + + /* + * If the state selected so far is shallow and this state's + * target residency matches the time till the closest timer + * event, select this one to avoid getting stuck in the shallow + * one for too long. + */ + if (drv->states[idx].target_residency_ns < TICK_NSEC && + s->target_residency_ns <= delta_tick) + idx = i; + + return idx; } if (idx == -1) @@ -482,10 +495,7 @@ 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++] = ktime_to_us(measured_ns); - if (data->interval_ptr >= INTERVALS) - data->interval_ptr = 0; + menu_update_intervals(data, ktime_to_us(measured_ns)); } /** |