diff options
Diffstat (limited to 'drivers/cpuidle/governors/menu.c')
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 68104434ebb5..f8e57c6303f2 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -18,6 +18,7 @@ #include <linux/hrtimer.h> #include <linux/tick.h> #include <linux/sched.h> +#include <linux/math64.h> #define BUCKETS 12 #define RESOLUTION 1024 @@ -100,7 +101,6 @@ struct menu_device { unsigned int expected_us; u64 predicted_us; - unsigned int measured_us; unsigned int exit_us; unsigned int bucket; u64 correction_factor[BUCKETS]; @@ -169,6 +169,12 @@ static DEFINE_PER_CPU(struct menu_device, menu_devices); static void menu_update(struct cpuidle_device *dev); +/* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */ +static u64 div_round64(u64 dividend, u32 divisor) +{ + return div_u64(dividend + (divisor / 2), divisor); +} + /** * menu_select - selects the next idle state to enter * @dev: the CPU @@ -180,14 +186,14 @@ static int menu_select(struct cpuidle_device *dev) int i; int multiplier; - data->last_state_idx = 0; - data->exit_us = 0; - if (data->needs_update) { menu_update(dev); data->needs_update = 0; } + data->last_state_idx = 0; + data->exit_us = 0; + /* Special case when user has set very strict latency requirement */ if (unlikely(latency_req == 0)) return 0; @@ -209,9 +215,8 @@ static int menu_select(struct cpuidle_device *dev) data->correction_factor[data->bucket] = RESOLUTION * DECAY; /* Make sure to round up for half microseconds */ - data->predicted_us = DIV_ROUND_CLOSEST( - data->expected_us * data->correction_factor[data->bucket], - RESOLUTION * DECAY); + data->predicted_us = div_round64(data->expected_us * data->correction_factor[data->bucket], + RESOLUTION * DECAY); /* * We want to default to C1 (hlt), not to busy polling @@ -288,7 +293,7 @@ static void menu_update(struct cpuidle_device *dev) new_factor = data->correction_factor[data->bucket] * (DECAY - 1) / DECAY; - if (data->expected_us > 0 && data->measured_us < MAX_INTERESTING) + if (data->expected_us > 0 && measured_us < MAX_INTERESTING) new_factor += RESOLUTION * measured_us / data->expected_us; else /* |