diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-08-20 12:39:18 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-08-20 12:39:18 +0200 |
commit | 170465ee7f5a9a2d0ac71285507e52642e040353 (patch) | |
tree | dbca81f04cde9e625170abbd6a72555cfbeb194e /drivers/cpuidle/governors/menu.c | |
parent | 169ad16bb87c10a3f7c108bb7008ebc0270f617a (diff) | |
parent | 1fca25427482387689fa27594c992a961d98768f (diff) |
Merge branch 'linus' into x86/xen
Diffstat (limited to 'drivers/cpuidle/governors/menu.c')
-rw-r--r-- | drivers/cpuidle/governors/menu.c | 42 |
1 files changed, 28 insertions, 14 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 78d77c5dc35..8d7cf3f3145 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -34,21 +34,28 @@ static DEFINE_PER_CPU(struct menu_device, menu_devices); static int menu_select(struct cpuidle_device *dev) { struct menu_device *data = &__get_cpu_var(menu_devices); + int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY); int i; + /* Special case when user has set very strict latency requirement */ + if (unlikely(latency_req == 0)) { + data->last_state_idx = 0; + return 0; + } + /* determine the expected residency time */ data->expected_us = (u32) ktime_to_ns(tick_nohz_get_sleep_length()) / 1000; /* find the deepest idle state that satisfies our constraints */ - for (i = 1; i < dev->state_count; i++) { + for (i = CPUIDLE_DRIVER_STATE_START + 1; i < dev->state_count; i++) { struct cpuidle_state *s = &dev->states[i]; if (s->target_residency > data->expected_us) break; if (s->target_residency > data->predicted_us) break; - if (s->exit_latency > pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY)) + if (s->exit_latency > latency_req) break; } @@ -67,9 +74,9 @@ static void menu_reflect(struct cpuidle_device *dev) { struct menu_device *data = &__get_cpu_var(menu_devices); int last_idx = data->last_state_idx; - unsigned int measured_us = - cpuidle_get_last_residency(dev) + data->elapsed_us; + unsigned int last_idle_us = cpuidle_get_last_residency(dev); struct cpuidle_state *target = &dev->states[last_idx]; + unsigned int measured_us; /* * Ugh, this idle state doesn't support residency measurements, so we @@ -77,20 +84,27 @@ static void menu_reflect(struct cpuidle_device *dev) * for one full standard timer tick. However, be aware that this * could potentially result in a suboptimal state transition. */ - if (!(target->flags & CPUIDLE_FLAG_TIME_VALID)) - measured_us = USEC_PER_SEC / HZ; + if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) + last_idle_us = USEC_PER_SEC / HZ; + + /* + * measured_us and elapsed_us are the cumulative idle time, since the + * last time we were woken out of idle by an interrupt. + */ + if (data->elapsed_us <= data->elapsed_us + last_idle_us) + measured_us = data->elapsed_us + last_idle_us; + else + measured_us = -1; + + /* Predict time until next break event */ + data->predicted_us = max(measured_us, data->last_measured_us); - /* Predict time remaining until next break event */ - if (measured_us + BREAK_FUZZ < data->expected_us - target->exit_latency) { - data->predicted_us = max(measured_us, data->last_measured_us); + if (last_idle_us + BREAK_FUZZ < + data->expected_us - target->exit_latency) { data->last_measured_us = measured_us; data->elapsed_us = 0; } else { - if (data->elapsed_us < data->elapsed_us + measured_us) - data->elapsed_us = measured_us; - else - data->elapsed_us = -1; - data->predicted_us = max(measured_us, data->last_measured_us); + data->elapsed_us = measured_us; } } |