X-Git-Url: http://git.onelab.eu/?p=linux-2.6.git;a=blobdiff_plain;f=drivers%2Fcpufreq%2Fcpufreq_ondemand.c;fp=drivers%2Fcpufreq%2Fcpufreq_ondemand.c;h=3e6ffcaa5af4c2a10941c2ad6d30478aead32897;hp=c1fc9c62bb51d0c1d2620f522d7c6ebbb0f432bc;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hpb=cee37fe97739d85991964371c1f3a745c00dd236 diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index c1fc9c62b..3e6ffcaa5 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -27,6 +27,7 @@ #include #include #include +#include /* * dbs is used in this file as a shortform for demandbased switching @@ -37,18 +38,21 @@ #define MIN_FREQUENCY_UP_THRESHOLD (11) #define MAX_FREQUENCY_UP_THRESHOLD (100) -/* - * The polling frequency of this governor depends on the capability of +/* + * The polling frequency of this governor depends on the capability of * the processor. Default polling frequency is 1000 times the transition - * latency of the processor. The governor will work on any processor with - * transition latency <= 10mS, using appropriate sampling + * latency of the processor. The governor will work on any processor with + * transition latency <= 10mS, using appropriate sampling * rate. * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) * this governor will not work. * All times here are in uS. */ -static unsigned int def_sampling_rate; -#define MIN_SAMPLING_RATE (def_sampling_rate / 2) +static unsigned int def_sampling_rate; +#define MIN_SAMPLING_RATE_RATIO (2) +/* for correct statistics, we need at least 10 ticks between each measure */ +#define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) +#define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) #define MAX_SAMPLING_RATE (500 * def_sampling_rate) #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) #define DEF_SAMPLING_DOWN_FACTOR (1) @@ -58,35 +62,38 @@ static unsigned int def_sampling_rate; static void do_dbs_timer(void *data); struct cpu_dbs_info_s { - struct cpufreq_policy *cur_policy; - unsigned int prev_cpu_idle_up; - unsigned int prev_cpu_idle_down; - unsigned int enable; + struct cpufreq_policy *cur_policy; + unsigned int prev_cpu_idle_up; + unsigned int prev_cpu_idle_down; + unsigned int enable; }; static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); static unsigned int dbs_enable; /* number of CPUs using this policy */ -static DECLARE_MUTEX (dbs_sem); +static DEFINE_MUTEX (dbs_mutex); static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); +static struct workqueue_struct *dbs_workq; + struct dbs_tuners { - unsigned int sampling_rate; - unsigned int sampling_down_factor; - unsigned int up_threshold; - unsigned int ignore_nice; + unsigned int sampling_rate; + unsigned int sampling_down_factor; + unsigned int up_threshold; + unsigned int ignore_nice; }; static struct dbs_tuners dbs_tuners_ins = { - .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, - .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, + .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, + .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, + .ignore_nice = 0, }; static inline unsigned int get_cpu_idle_time(unsigned int cpu) { return kstat_cpu(cpu).cpustat.idle + kstat_cpu(cpu).cpustat.iowait + - ( !dbs_tuners_ins.ignore_nice ? + ( dbs_tuners_ins.ignore_nice ? kstat_cpu(cpu).cpustat.nice : 0); } @@ -102,8 +109,8 @@ static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); } -#define define_one_ro(_name) \ -static struct freq_attr _name = \ +#define define_one_ro(_name) \ +static struct freq_attr _name = \ __ATTR(_name, 0444, show_##_name, NULL) define_one_ro(sampling_rate_max); @@ -119,9 +126,9 @@ static ssize_t show_##file_name \ show_one(sampling_rate, sampling_rate); show_one(sampling_down_factor, sampling_down_factor); show_one(up_threshold, up_threshold); -show_one(ignore_nice, ignore_nice); +show_one(ignore_nice_load, ignore_nice); -static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, +static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, const char *buf, size_t count) { unsigned int input; @@ -133,70 +140,70 @@ static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) return -EINVAL; - down(&dbs_sem); + mutex_lock(&dbs_mutex); dbs_tuners_ins.sampling_down_factor = input; - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return count; } -static ssize_t store_sampling_rate(struct cpufreq_policy *unused, +static ssize_t store_sampling_rate(struct cpufreq_policy *unused, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf (buf, "%u", &input); - down(&dbs_sem); + mutex_lock(&dbs_mutex); if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return -EINVAL; } dbs_tuners_ins.sampling_rate = input; - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return count; } -static ssize_t store_up_threshold(struct cpufreq_policy *unused, +static ssize_t store_up_threshold(struct cpufreq_policy *unused, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf (buf, "%u", &input); - down(&dbs_sem); - if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || + mutex_lock(&dbs_mutex); + if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return -EINVAL; } dbs_tuners_ins.up_threshold = input; - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return count; } -static ssize_t store_ignore_nice(struct cpufreq_policy *policy, +static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, const char *buf, size_t count) { unsigned int input; int ret; unsigned int j; - + ret = sscanf (buf, "%u", &input); if ( ret != 1 ) return -EINVAL; if ( input > 1 ) input = 1; - - down(&dbs_sem); + + mutex_lock(&dbs_mutex); if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return count; } dbs_tuners_ins.ignore_nice = input; @@ -208,7 +215,7 @@ static ssize_t store_ignore_nice(struct cpufreq_policy *policy, j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; } - up(&dbs_sem); + mutex_unlock(&dbs_mutex); return count; } @@ -220,7 +227,7 @@ __ATTR(_name, 0644, show_##_name, store_##_name) define_one_rw(sampling_rate); define_one_rw(sampling_down_factor); define_one_rw(up_threshold); -define_one_rw(ignore_nice); +define_one_rw(ignore_nice_load); static struct attribute * dbs_attributes[] = { &sampling_rate_max.attr, @@ -228,7 +235,7 @@ static struct attribute * dbs_attributes[] = { &sampling_rate.attr, &sampling_down_factor.attr, &up_threshold.attr, - &ignore_nice.attr, + &ignore_nice_load.attr, NULL }; @@ -255,16 +262,16 @@ static void dbs_check_cpu(int cpu) return; policy = this_dbs_info->cur_policy; - /* + /* * Every sampling_rate, we check, if current idle time is less * than 20% (default), then we try to increase frequency * Every sampling_rate*sampling_down_factor, we look for a the lowest * frequency which can sustain the load while keeping idle time over * 30%. If such a frequency exist, we try to decrease to this frequency. * - * Any frequency increase takes it to the maximum frequency. - * Frequency reduction happens at minimum steps of - * 5% (default) of current frequency + * Any frequency increase takes it to the maximum frequency. + * Frequency reduction happens at minimum steps of + * 5% (default) of current frequency */ /* Check for frequency increase */ @@ -294,14 +301,14 @@ static void dbs_check_cpu(int cpu) struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(cpu_dbs_info, j); - j_dbs_info->prev_cpu_idle_down = + j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; } /* if we are already at full speed then break out early */ if (policy->cur == policy->max) return; - - __cpufreq_driver_target(policy, policy->max, + + __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H); return; } @@ -343,36 +350,45 @@ static void dbs_check_cpu(int cpu) * policy. To be safe, we focus 10 points under the threshold. */ freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; - freq_next = (freq_next * policy->cur) / + freq_next = (freq_next * policy->cur) / (dbs_tuners_ins.up_threshold - 10); + if (freq_next < policy->min) + freq_next = policy->min; + if (freq_next <= ((policy->cur * 95) / 100)) __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); } static void do_dbs_timer(void *data) -{ +{ int i; - down(&dbs_sem); + mutex_lock(&dbs_mutex); for_each_online_cpu(i) dbs_check_cpu(i); - schedule_delayed_work(&dbs_work, - usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); - up(&dbs_sem); -} + queue_delayed_work(dbs_workq, &dbs_work, + usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); + mutex_unlock(&dbs_mutex); +} static inline void dbs_timer_init(void) { INIT_WORK(&dbs_work, do_dbs_timer, NULL); - schedule_delayed_work(&dbs_work, - usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); + if (!dbs_workq) + dbs_workq = create_singlethread_workqueue("ondemand"); + if (!dbs_workq) { + printk(KERN_ERR "ondemand: Cannot initialize kernel thread\n"); + return; + } + queue_delayed_work(dbs_workq, &dbs_work, + usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); return; } static inline void dbs_timer_exit(void) { - cancel_delayed_work(&dbs_work); - return; + if (dbs_workq) + cancel_rearming_delayed_workqueue(dbs_workq, &dbs_work); } static int cpufreq_governor_dbs(struct cpufreq_policy *policy, @@ -386,22 +402,25 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, switch (event) { case CPUFREQ_GOV_START: - if ((!cpu_online(cpu)) || + if ((!cpu_online(cpu)) || (!policy->cur)) return -EINVAL; if (policy->cpuinfo.transition_latency > - (TRANSITION_LATENCY_LIMIT * 1000)) + (TRANSITION_LATENCY_LIMIT * 1000)) { + printk(KERN_WARNING "ondemand governor failed to load " + "due to too long transition latency\n"); return -EINVAL; + } if (this_dbs_info->enable) /* Already enabled */ break; - - down(&dbs_sem); + + mutex_lock(&dbs_mutex); for_each_cpu_mask(j, policy->cpus) { struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(cpu_dbs_info, j); j_dbs_info->cur_policy = policy; - + j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; @@ -416,24 +435,25 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, if (dbs_enable == 1) { unsigned int latency; /* policy latency is in nS. Convert it to uS first */ + latency = policy->cpuinfo.transition_latency / 1000; + if (latency == 0) + latency = 1; - latency = policy->cpuinfo.transition_latency; - if (latency < 1000) - latency = 1000; - - def_sampling_rate = (latency / 1000) * + def_sampling_rate = latency * DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; - dbs_tuners_ins.sampling_rate = def_sampling_rate; - dbs_tuners_ins.ignore_nice = 0; + if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) + def_sampling_rate = MIN_STAT_SAMPLING_RATE; + + dbs_tuners_ins.sampling_rate = def_sampling_rate; dbs_timer_init(); } - - up(&dbs_sem); + + mutex_unlock(&dbs_mutex); break; case CPUFREQ_GOV_STOP: - down(&dbs_sem); + mutex_lock(&dbs_mutex); this_dbs_info->enable = 0; sysfs_remove_group(&policy->kobj, &dbs_attr_group); dbs_enable--; @@ -441,24 +461,24 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, * Stop the timerschedule work, when this governor * is used for first time */ - if (dbs_enable == 0) + if (dbs_enable == 0) dbs_timer_exit(); - - up(&dbs_sem); + + mutex_unlock(&dbs_mutex); break; case CPUFREQ_GOV_LIMITS: - down(&dbs_sem); + mutex_lock(&dbs_mutex); if (policy->max < this_dbs_info->cur_policy->cur) __cpufreq_driver_target( this_dbs_info->cur_policy, - policy->max, CPUFREQ_RELATION_H); + policy->max, CPUFREQ_RELATION_H); else if (policy->min > this_dbs_info->cur_policy->cur) __cpufreq_driver_target( this_dbs_info->cur_policy, - policy->min, CPUFREQ_RELATION_L); - up(&dbs_sem); + policy->min, CPUFREQ_RELATION_L); + mutex_unlock(&dbs_mutex); break; } return 0; @@ -477,8 +497,12 @@ static int __init cpufreq_gov_dbs_init(void) static void __exit cpufreq_gov_dbs_exit(void) { - /* Make sure that the scheduled work is indeed not running */ - flush_scheduled_work(); + /* Make sure that the scheduled work is indeed not running. + Assumes the timer has been cancelled first. */ + if (dbs_workq) { + flush_workqueue(dbs_workq); + destroy_workqueue(dbs_workq); + } cpufreq_unregister_governor(&cpufreq_gov_dbs); }