X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fcpufreq%2Fcpufreq_ondemand.c;fp=drivers%2Fcpufreq%2Fcpufreq_ondemand.c;h=9ee9411f186f9b8738f4a7320991f058576733d7;hb=64ba3f394c830ec48a1c31b53dcae312c56f1604;hp=52cf1f02182591f64f527144e1e3a1394ee9a050;hpb=be1e6109ac94a859551f8e1774eb9a8469fe055c;p=linux-2.6.git diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 52cf1f021..9ee9411f1 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -12,11 +12,21 @@ #include #include +#include #include +#include +#include #include -#include +#include +#include +#include +#include +#include +#include +#include #include #include +#include #include /* @@ -28,72 +38,61 @@ #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; +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) +#define MAX_SAMPLING_DOWN_FACTOR (10) #define TRANSITION_LATENCY_LIMIT (10 * 1000) static void do_dbs_timer(void *data); struct cpu_dbs_info_s { - cputime64_t prev_cpu_idle; - cputime64_t prev_cpu_wall; - struct cpufreq_policy *cur_policy; - struct work_struct work; - 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 */ -/* - * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug - * lock and dbs_mutex. cpu_hotplug lock should always be held before - * dbs_mutex. If any function that can potentially take cpu_hotplug lock - * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then - * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock - * is recursive for the same process. -Venki - */ -static DEFINE_MUTEX(dbs_mutex); - -static struct workqueue_struct *kondemand_wq; +static DEFINE_MUTEX (dbs_mutex); +static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); struct dbs_tuners { - unsigned int sampling_rate; - 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, - .ignore_nice = 0, + .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, + .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, }; -static inline cputime64_t get_cpu_idle_time(unsigned int cpu) +static inline unsigned int get_cpu_idle_time(unsigned int cpu) { - cputime64_t retval; - - retval = cputime64_add(kstat_cpu(cpu).cpustat.idle, - kstat_cpu(cpu).cpustat.iowait); - - if (dbs_tuners_ins.ignore_nice) - retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice); - - return retval; + return kstat_cpu(cpu).cpustat.idle + + kstat_cpu(cpu).cpustat.iowait + + ( dbs_tuners_ins.ignore_nice ? + kstat_cpu(cpu).cpustat.nice : + 0); } /************************** sysfs interface ************************/ @@ -107,8 +106,8 @@ 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); @@ -122,15 +121,35 @@ static ssize_t show_##file_name \ return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ } show_one(sampling_rate, sampling_rate); +show_one(sampling_down_factor, sampling_down_factor); show_one(up_threshold, up_threshold); show_one(ignore_nice_load, ignore_nice); -static ssize_t store_sampling_rate(struct cpufreq_policy *unused, +static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, + const char *buf, size_t count) +{ + unsigned int input; + int ret; + ret = sscanf (buf, "%u", &input); + if (ret != 1 ) + return -EINVAL; + + if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) + return -EINVAL; + + mutex_lock(&dbs_mutex); + dbs_tuners_ins.sampling_down_factor = input; + mutex_unlock(&dbs_mutex); + + return count; +} + +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); + ret = sscanf (buf, "%u", &input); mutex_lock(&dbs_mutex); if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { @@ -144,15 +163,15 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused, 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); + ret = sscanf (buf, "%u", &input); mutex_lock(&dbs_mutex); - if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || + if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { mutex_unlock(&dbs_mutex); return -EINVAL; @@ -171,14 +190,14 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, int ret; unsigned int j; - - ret = sscanf(buf, "%u", &input); + + ret = sscanf (buf, "%u", &input); if ( ret != 1 ) return -EINVAL; if ( input > 1 ) input = 1; - + mutex_lock(&dbs_mutex); if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ mutex_unlock(&dbs_mutex); @@ -186,12 +205,12 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, } dbs_tuners_ins.ignore_nice = input; - /* we need to re-evaluate prev_cpu_idle */ + /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ for_each_online_cpu(j) { - struct cpu_dbs_info_s *dbs_info; - dbs_info = &per_cpu(cpu_dbs_info, j); - dbs_info->prev_cpu_idle = get_cpu_idle_time(j); - dbs_info->prev_cpu_wall = get_jiffies_64(); + struct cpu_dbs_info_s *j_dbs_info; + j_dbs_info = &per_cpu(cpu_dbs_info, j); + 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; } mutex_unlock(&dbs_mutex); @@ -203,6 +222,7 @@ static struct freq_attr _name = \ __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_load); @@ -210,6 +230,7 @@ static struct attribute * dbs_attributes[] = { &sampling_rate_max.attr, &sampling_rate_min.attr, &sampling_rate.attr, + &sampling_down_factor.attr, &up_threshold.attr, &ignore_nice_load.attr, NULL @@ -222,115 +243,140 @@ static struct attribute_group dbs_attr_group = { /************************** sysfs end ************************/ -static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) +static void dbs_check_cpu(int cpu) { - unsigned int idle_ticks, total_ticks; - unsigned int load; - cputime64_t cur_jiffies; + unsigned int idle_ticks, up_idle_ticks, total_ticks; + unsigned int freq_next; + unsigned int freq_down_sampling_rate; + static int down_skip[NR_CPUS]; + struct cpu_dbs_info_s *this_dbs_info; struct cpufreq_policy *policy; unsigned int j; + this_dbs_info = &per_cpu(cpu_dbs_info, cpu); if (!this_dbs_info->enable) return; policy = this_dbs_info->cur_policy; - cur_jiffies = jiffies64_to_cputime64(get_jiffies_64()); - total_ticks = (unsigned int) cputime64_sub(cur_jiffies, - this_dbs_info->prev_cpu_wall); - this_dbs_info->prev_cpu_wall = cur_jiffies; - if (!total_ticks) - return; - /* + /* * Every sampling_rate, we check, if current idle time is less * than 20% (default), then we try to increase frequency - * Every sampling_rate, we look for a the lowest + * 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 */ - /* Get Idle Time */ + /* Check for frequency increase */ idle_ticks = UINT_MAX; for_each_cpu_mask(j, policy->cpus) { - cputime64_t total_idle_ticks; - unsigned int tmp_idle_ticks; + unsigned int tmp_idle_ticks, total_idle_ticks; struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(cpu_dbs_info, j); total_idle_ticks = get_cpu_idle_time(j); - tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks, - j_dbs_info->prev_cpu_idle); - j_dbs_info->prev_cpu_idle = total_idle_ticks; + tmp_idle_ticks = total_idle_ticks - + j_dbs_info->prev_cpu_idle_up; + j_dbs_info->prev_cpu_idle_up = total_idle_ticks; if (tmp_idle_ticks < idle_ticks) idle_ticks = tmp_idle_ticks; } - load = (100 * (total_ticks - idle_ticks)) / total_ticks; - /* Check for frequency increase */ - if (load > dbs_tuners_ins.up_threshold) { + /* Scale idle ticks by 100 and compare with up and down ticks */ + idle_ticks *= 100; + up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * + usecs_to_jiffies(dbs_tuners_ins.sampling_rate); + + if (idle_ticks < up_idle_ticks) { + down_skip[cpu] = 0; + 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->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; } /* Check for frequency decrease */ + down_skip[cpu]++; + if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) + return; + + idle_ticks = UINT_MAX; + for_each_cpu_mask(j, policy->cpus) { + unsigned int tmp_idle_ticks, total_idle_ticks; + struct cpu_dbs_info_s *j_dbs_info; + + j_dbs_info = &per_cpu(cpu_dbs_info, j); + /* Check for frequency decrease */ + total_idle_ticks = j_dbs_info->prev_cpu_idle_up; + tmp_idle_ticks = total_idle_ticks - + j_dbs_info->prev_cpu_idle_down; + j_dbs_info->prev_cpu_idle_down = total_idle_ticks; + + if (tmp_idle_ticks < idle_ticks) + idle_ticks = tmp_idle_ticks; + } + + down_skip[cpu] = 0; /* if we cannot reduce the frequency anymore, break out early */ if (policy->cur == policy->min) return; + /* Compute how many ticks there are between two measurements */ + freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * + dbs_tuners_ins.sampling_down_factor; + total_ticks = usecs_to_jiffies(freq_down_sampling_rate); + /* * The optimal frequency is the frequency that is the lowest that * can support the current CPU usage without triggering the up * policy. To be safe, we focus 10 points under the threshold. */ - if (load < (dbs_tuners_ins.up_threshold - 10)) { - unsigned int freq_next; - freq_next = (policy->cur * load) / + freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; + freq_next = (freq_next * policy->cur) / (dbs_tuners_ins.up_threshold - 10); + if (freq_next <= ((policy->cur * 95) / 100)) __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); - } } static void do_dbs_timer(void *data) -{ - unsigned int cpu = smp_processor_id(); - struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); - - if (!dbs_info->enable) - return; - - lock_cpu_hotplug(); - dbs_check_cpu(dbs_info); - unlock_cpu_hotplug(); - queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, +{ + int i; + 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)); -} + mutex_unlock(&dbs_mutex); +} -static inline void dbs_timer_init(unsigned int cpu) +static inline void dbs_timer_init(void) { - struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); - - INIT_WORK(&dbs_info->work, do_dbs_timer, 0); - queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, + INIT_WORK(&dbs_work, do_dbs_timer, NULL); + schedule_delayed_work(&dbs_work, usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); return; } -static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) +static inline void dbs_timer_exit(void) { - dbs_info->enable = 0; - cancel_delayed_work(&dbs_info->work); - flush_workqueue(kondemand_wq); + cancel_delayed_work(&dbs_work); + return; } static int cpufreq_governor_dbs(struct cpufreq_policy *policy, @@ -344,39 +390,29 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, switch (event) { case CPUFREQ_GOV_START: - if ((!cpu_online(cpu)) || (!policy->cur)) + if ((!cpu_online(cpu)) || + (!policy->cur)) return -EINVAL; if (policy->cpuinfo.transition_latency > - (TRANSITION_LATENCY_LIMIT * 1000)) { - printk(KERN_WARNING "ondemand governor failed to load " - "due to too long transition latency\n"); + (TRANSITION_LATENCY_LIMIT * 1000)) return -EINVAL; - } if (this_dbs_info->enable) /* Already enabled */ break; - + mutex_lock(&dbs_mutex); - dbs_enable++; - if (dbs_enable == 1) { - kondemand_wq = create_workqueue("kondemand"); - if (!kondemand_wq) { - printk(KERN_ERR "Creation of kondemand failed\n"); - dbs_enable--; - mutex_unlock(&dbs_mutex); - return -ENOSPC; - } - } 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 = get_cpu_idle_time(j); - j_dbs_info->prev_cpu_wall = get_jiffies_64(); + + 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; } this_dbs_info->enable = 1; sysfs_create_group(&policy->kobj, &dbs_attr_group); + dbs_enable++; /* * Start the timerschedule work, when this governor * is used for first time @@ -395,20 +431,26 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, def_sampling_rate = MIN_STAT_SAMPLING_RATE; dbs_tuners_ins.sampling_rate = def_sampling_rate; - } - dbs_timer_init(policy->cpu); + dbs_tuners_ins.ignore_nice = 0; + dbs_timer_init(); + } + mutex_unlock(&dbs_mutex); break; case CPUFREQ_GOV_STOP: mutex_lock(&dbs_mutex); - dbs_timer_exit(this_dbs_info); + this_dbs_info->enable = 0; sysfs_remove_group(&policy->kobj, &dbs_attr_group); dbs_enable--; - if (dbs_enable == 0) - destroy_workqueue(kondemand_wq); - + /* + * Stop the timerschedule work, when this governor + * is used for first time + */ + if (dbs_enable == 0) + dbs_timer_exit(); + mutex_unlock(&dbs_mutex); break; @@ -416,13 +458,13 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, case CPUFREQ_GOV_LIMITS: 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); + __cpufreq_driver_target( + this_dbs_info->cur_policy, + 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); + __cpufreq_driver_target( + this_dbs_info->cur_policy, + policy->min, CPUFREQ_RELATION_L); mutex_unlock(&dbs_mutex); break; } @@ -430,9 +472,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, } static struct cpufreq_governor cpufreq_gov_dbs = { - .name = "ondemand", - .governor = cpufreq_governor_dbs, - .owner = THIS_MODULE, + .name = "ondemand", + .governor = cpufreq_governor_dbs, + .owner = THIS_MODULE, }; static int __init cpufreq_gov_dbs_init(void) @@ -442,15 +484,17 @@ 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(); + cpufreq_unregister_governor(&cpufreq_gov_dbs); } -MODULE_AUTHOR("Venkatesh Pallipadi "); -MODULE_AUTHOR("Alexey Starikovskiy "); -MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " - "Low Latency Frequency Transition capable processors"); -MODULE_LICENSE("GPL"); +MODULE_AUTHOR ("Venkatesh Pallipadi "); +MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " + "Low Latency Frequency Transition capable processors"); +MODULE_LICENSE ("GPL"); module_init(cpufreq_gov_dbs_init); module_exit(cpufreq_gov_dbs_exit);