| /* |
| * drivers/cpufreq/cpufreq_ondemand.c |
| * |
| * Copyright (C) 2001 Russell King |
| * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. |
| * Jun Nakajima <jun.nakajima@intel.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/cpufreq.h> |
| #include <linux/cpu.h> |
| #include <linux/jiffies.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/mutex.h> |
| #include <linux/hrtimer.h> |
| #include <linux/tick.h> |
| #include <linux/ktime.h> |
| |
| /* |
| * dbs is used in this file as a shortform for demandbased switching |
| * It helps to keep variable names smaller, simpler |
| */ |
| |
| #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) |
| #define DEF_FREQUENCY_UP_THRESHOLD (80) |
| #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) |
| #define MICRO_FREQUENCY_UP_THRESHOLD (95) |
| #define MIN_FREQUENCY_UP_THRESHOLD (11) |
| #define MAX_FREQUENCY_UP_THRESHOLD (100) |
| |
| /* |
| * 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 |
| * 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_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 TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
| |
| static void do_dbs_timer(struct work_struct *work); |
| |
| /* Sampling types */ |
| enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; |
| |
| struct cpu_dbs_info_s { |
| cputime64_t prev_cpu_idle; |
| cputime64_t prev_cpu_wall; |
| cputime64_t prev_cpu_nice; |
| struct cpufreq_policy *cur_policy; |
| struct delayed_work work; |
| struct cpufreq_frequency_table *freq_table; |
| unsigned int freq_lo; |
| unsigned int freq_lo_jiffies; |
| unsigned int freq_hi_jiffies; |
| int cpu; |
| unsigned int enable:1, |
| sample_type:1; |
| }; |
| 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 struct dbs_tuners { |
| unsigned int sampling_rate; |
| unsigned int up_threshold; |
| unsigned int down_differential; |
| unsigned int ignore_nice; |
| unsigned int powersave_bias; |
| } dbs_tuners_ins = { |
| .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
| .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, |
| .ignore_nice = 0, |
| .powersave_bias = 0, |
| }; |
| |
| static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, |
| cputime64_t *wall) |
| { |
| cputime64_t idle_time; |
| cputime64_t cur_wall_time; |
| cputime64_t busy_time; |
| |
| cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); |
| busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user, |
| kstat_cpu(cpu).cpustat.system); |
| |
| busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq); |
| busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq); |
| busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal); |
| |
| if (!dbs_tuners_ins.ignore_nice) { |
| busy_time = cputime64_add(busy_time, |
| kstat_cpu(cpu).cpustat.nice); |
| } |
| |
| idle_time = cputime64_sub(cur_wall_time, busy_time); |
| if (wall) |
| *wall = cur_wall_time; |
| |
| return idle_time; |
| } |
| |
| static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) |
| { |
| u64 idle_time = get_cpu_idle_time_us(cpu, wall); |
| |
| if (idle_time == -1ULL) |
| return get_cpu_idle_time_jiffy(cpu, wall); |
| |
| if (dbs_tuners_ins.ignore_nice) { |
| cputime64_t cur_nice; |
| unsigned long cur_nice_jiffies; |
| struct cpu_dbs_info_s *dbs_info; |
| |
| dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| cur_nice = cputime64_sub(kstat_cpu(cpu).cpustat.nice, |
| dbs_info->prev_cpu_nice); |
| /* |
| * Assumption: nice time between sampling periods will be |
| * less than 2^32 jiffies for 32 bit sys |
| */ |
| cur_nice_jiffies = (unsigned long) |
| cputime64_to_jiffies64(cur_nice); |
| dbs_info->prev_cpu_nice = kstat_cpu(cpu).cpustat.nice; |
| return idle_time + jiffies_to_usecs(cur_nice_jiffies); |
| } |
| return idle_time; |
| } |
| |
| /* |
| * Find right freq to be set now with powersave_bias on. |
| * Returns the freq_hi to be used right now and will set freq_hi_jiffies, |
| * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. |
| */ |
| static unsigned int powersave_bias_target(struct cpufreq_policy *policy, |
| unsigned int freq_next, |
| unsigned int relation) |
| { |
| unsigned int freq_req, freq_reduc, freq_avg; |
| unsigned int freq_hi, freq_lo; |
| unsigned int index = 0; |
| unsigned int jiffies_total, jiffies_hi, jiffies_lo; |
| struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu); |
| |
| if (!dbs_info->freq_table) { |
| dbs_info->freq_lo = 0; |
| dbs_info->freq_lo_jiffies = 0; |
| return freq_next; |
| } |
| |
| cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, |
| relation, &index); |
| freq_req = dbs_info->freq_table[index].frequency; |
| freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; |
| freq_avg = freq_req - freq_reduc; |
| |
| /* Find freq bounds for freq_avg in freq_table */ |
| index = 0; |
| cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, |
| CPUFREQ_RELATION_H, &index); |
| freq_lo = dbs_info->freq_table[index].frequency; |
| index = 0; |
| cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, |
| CPUFREQ_RELATION_L, &index); |
| freq_hi = dbs_info->freq_table[index].frequency; |
| |
| /* Find out how long we have to be in hi and lo freqs */ |
| if (freq_hi == freq_lo) { |
| dbs_info->freq_lo = 0; |
| dbs_info->freq_lo_jiffies = 0; |
| return freq_lo; |
| } |
| jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| jiffies_hi = (freq_avg - freq_lo) * jiffies_total; |
| jiffies_hi += ((freq_hi - freq_lo) / 2); |
| jiffies_hi /= (freq_hi - freq_lo); |
| jiffies_lo = jiffies_total - jiffies_hi; |
| dbs_info->freq_lo = freq_lo; |
| dbs_info->freq_lo_jiffies = jiffies_lo; |
| dbs_info->freq_hi_jiffies = jiffies_hi; |
| return freq_hi; |
| } |
| |
| static void ondemand_powersave_bias_init(void) |
| { |
| int i; |
| for_each_online_cpu(i) { |
| struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i); |
| dbs_info->freq_table = cpufreq_frequency_get_table(i); |
| dbs_info->freq_lo = 0; |
| } |
| } |
| |
| /************************** sysfs interface ************************/ |
| static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) |
| { |
| return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); |
| } |
| |
| 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 = \ |
| __ATTR(_name, 0444, show_##_name, NULL) |
| |
| define_one_ro(sampling_rate_max); |
| define_one_ro(sampling_rate_min); |
| |
| /* cpufreq_ondemand Governor Tunables */ |
| #define show_one(file_name, object) \ |
| static ssize_t show_##file_name \ |
| (struct cpufreq_policy *unused, char *buf) \ |
| { \ |
| return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ |
| } |
| show_one(sampling_rate, sampling_rate); |
| show_one(up_threshold, up_threshold); |
| show_one(ignore_nice_load, ignore_nice); |
| show_one(powersave_bias, powersave_bias); |
| |
| 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); |
| |
| mutex_lock(&dbs_mutex); |
| if (ret != 1 || input > MAX_SAMPLING_RATE |
| || input < MIN_SAMPLING_RATE) { |
| mutex_unlock(&dbs_mutex); |
| return -EINVAL; |
| } |
| |
| dbs_tuners_ins.sampling_rate = input; |
| mutex_unlock(&dbs_mutex); |
| |
| return count; |
| } |
| |
| 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); |
| |
| mutex_lock(&dbs_mutex); |
| if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
| input < MIN_FREQUENCY_UP_THRESHOLD) { |
| mutex_unlock(&dbs_mutex); |
| return -EINVAL; |
| } |
| |
| dbs_tuners_ins.up_threshold = input; |
| mutex_unlock(&dbs_mutex); |
| |
| return count; |
| } |
| |
| 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; |
| |
| mutex_lock(&dbs_mutex); |
| if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
| mutex_unlock(&dbs_mutex); |
| return count; |
| } |
| dbs_tuners_ins.ignore_nice = input; |
| |
| /* we need to re-evaluate prev_cpu_idle */ |
| 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); |
| } |
| mutex_unlock(&dbs_mutex); |
| |
| return count; |
| } |
| |
| static ssize_t store_powersave_bias(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 > 1000) |
| input = 1000; |
| |
| mutex_lock(&dbs_mutex); |
| dbs_tuners_ins.powersave_bias = input; |
| ondemand_powersave_bias_init(); |
| mutex_unlock(&dbs_mutex); |
| |
| return count; |
| } |
| |
| #define define_one_rw(_name) \ |
| static struct freq_attr _name = \ |
| __ATTR(_name, 0644, show_##_name, store_##_name) |
| |
| define_one_rw(sampling_rate); |
| define_one_rw(up_threshold); |
| define_one_rw(ignore_nice_load); |
| define_one_rw(powersave_bias); |
| |
| static struct attribute * dbs_attributes[] = { |
| &sampling_rate_max.attr, |
| &sampling_rate_min.attr, |
| &sampling_rate.attr, |
| &up_threshold.attr, |
| &ignore_nice_load.attr, |
| &powersave_bias.attr, |
| NULL |
| }; |
| |
| static struct attribute_group dbs_attr_group = { |
| .attrs = dbs_attributes, |
| .name = "ondemand", |
| }; |
| |
| /************************** sysfs end ************************/ |
| |
| static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
| { |
| unsigned int max_load_freq; |
| |
| struct cpufreq_policy *policy; |
| unsigned int j; |
| |
| if (!this_dbs_info->enable) |
| return; |
| |
| this_dbs_info->freq_lo = 0; |
| 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, 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 |
| */ |
| |
| /* Get Absolute Load - in terms of freq */ |
| max_load_freq = 0; |
| |
| for_each_cpu_mask_nr(j, policy->cpus) { |
| struct cpu_dbs_info_s *j_dbs_info; |
| cputime64_t cur_wall_time, cur_idle_time; |
| unsigned int idle_time, wall_time; |
| unsigned int load, load_freq; |
| int freq_avg; |
| |
| j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| |
| cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); |
| |
| wall_time = (unsigned int) cputime64_sub(cur_wall_time, |
| j_dbs_info->prev_cpu_wall); |
| j_dbs_info->prev_cpu_wall = cur_wall_time; |
| |
| idle_time = (unsigned int) cputime64_sub(cur_idle_time, |
| j_dbs_info->prev_cpu_idle); |
| j_dbs_info->prev_cpu_idle = cur_idle_time; |
| |
| if (unlikely(!wall_time || wall_time < idle_time)) |
| continue; |
| |
| load = 100 * (wall_time - idle_time) / wall_time; |
| |
| freq_avg = __cpufreq_driver_getavg(policy, j); |
| if (freq_avg <= 0) |
| freq_avg = policy->cur; |
| |
| load_freq = load * freq_avg; |
| if (load_freq > max_load_freq) |
| max_load_freq = load_freq; |
| } |
| |
| /* Check for frequency increase */ |
| if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { |
| /* if we are already at full speed then break out early */ |
| if (!dbs_tuners_ins.powersave_bias) { |
| if (policy->cur == policy->max) |
| return; |
| |
| __cpufreq_driver_target(policy, policy->max, |
| CPUFREQ_RELATION_H); |
| } else { |
| int freq = powersave_bias_target(policy, policy->max, |
| CPUFREQ_RELATION_H); |
| __cpufreq_driver_target(policy, freq, |
| CPUFREQ_RELATION_L); |
| } |
| return; |
| } |
| |
| /* Check for frequency decrease */ |
| /* if we cannot reduce the frequency anymore, break out early */ |
| if (policy->cur == policy->min) |
| return; |
| |
| /* |
| * 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 (max_load_freq < |
| (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) * |
| policy->cur) { |
| unsigned int freq_next; |
| freq_next = max_load_freq / |
| (dbs_tuners_ins.up_threshold - |
| dbs_tuners_ins.down_differential); |
| |
| if (!dbs_tuners_ins.powersave_bias) { |
| __cpufreq_driver_target(policy, freq_next, |
| CPUFREQ_RELATION_L); |
| } else { |
| int freq = powersave_bias_target(policy, freq_next, |
| CPUFREQ_RELATION_L); |
| __cpufreq_driver_target(policy, freq, |
| CPUFREQ_RELATION_L); |
| } |
| } |
| } |
| |
| static void do_dbs_timer(struct work_struct *work) |
| { |
| struct cpu_dbs_info_s *dbs_info = |
| container_of(work, struct cpu_dbs_info_s, work.work); |
| unsigned int cpu = dbs_info->cpu; |
| int sample_type = dbs_info->sample_type; |
| |
| /* We want all CPUs to do sampling nearly on same jiffy */ |
| int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| |
| delay -= jiffies % delay; |
| |
| if (lock_policy_rwsem_write(cpu) < 0) |
| return; |
| |
| if (!dbs_info->enable) { |
| unlock_policy_rwsem_write(cpu); |
| return; |
| } |
| |
| /* Common NORMAL_SAMPLE setup */ |
| dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
| if (!dbs_tuners_ins.powersave_bias || |
| sample_type == DBS_NORMAL_SAMPLE) { |
| dbs_check_cpu(dbs_info); |
| if (dbs_info->freq_lo) { |
| /* Setup timer for SUB_SAMPLE */ |
| dbs_info->sample_type = DBS_SUB_SAMPLE; |
| delay = dbs_info->freq_hi_jiffies; |
| } |
| } else { |
| __cpufreq_driver_target(dbs_info->cur_policy, |
| dbs_info->freq_lo, |
| CPUFREQ_RELATION_H); |
| } |
| queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay); |
| unlock_policy_rwsem_write(cpu); |
| } |
| |
| static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
| { |
| /* We want all CPUs to do sampling nearly on same jiffy */ |
| int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| delay -= jiffies % delay; |
| |
| dbs_info->enable = 1; |
| ondemand_powersave_bias_init(); |
| dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
| INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); |
| queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work, |
| delay); |
| } |
| |
| static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
| { |
| dbs_info->enable = 0; |
| cancel_delayed_work(&dbs_info->work); |
| } |
| |
| static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| unsigned int event) |
| { |
| unsigned int cpu = policy->cpu; |
| struct cpu_dbs_info_s *this_dbs_info; |
| unsigned int j; |
| int rc; |
| |
| this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| |
| switch (event) { |
| case CPUFREQ_GOV_START: |
| if ((!cpu_online(cpu)) || (!policy->cur)) |
| return -EINVAL; |
| |
| if (this_dbs_info->enable) /* Already enabled */ |
| break; |
| |
| mutex_lock(&dbs_mutex); |
| dbs_enable++; |
| |
| rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); |
| if (rc) { |
| dbs_enable--; |
| mutex_unlock(&dbs_mutex); |
| return rc; |
| } |
| |
| for_each_cpu_mask_nr(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); |
| } |
| this_dbs_info->cpu = cpu; |
| /* |
| * Start the timerschedule work, when this governor |
| * is used for first time |
| */ |
| 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; |
| |
| def_sampling_rate = latency * |
| DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
| |
| 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(this_dbs_info); |
| |
| mutex_unlock(&dbs_mutex); |
| break; |
| |
| case CPUFREQ_GOV_STOP: |
| mutex_lock(&dbs_mutex); |
| dbs_timer_exit(this_dbs_info); |
| sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
| dbs_enable--; |
| mutex_unlock(&dbs_mutex); |
| |
| break; |
| |
| 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); |
| else if (policy->min > this_dbs_info->cur_policy->cur) |
| __cpufreq_driver_target(this_dbs_info->cur_policy, |
| policy->min, |
| CPUFREQ_RELATION_L); |
| mutex_unlock(&dbs_mutex); |
| break; |
| } |
| return 0; |
| } |
| |
| #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
| static |
| #endif |
| struct cpufreq_governor cpufreq_gov_ondemand = { |
| .name = "ondemand", |
| .governor = cpufreq_governor_dbs, |
| .max_transition_latency = TRANSITION_LATENCY_LIMIT, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init cpufreq_gov_dbs_init(void) |
| { |
| int err; |
| cputime64_t wall; |
| u64 idle_time = get_cpu_idle_time_us(smp_processor_id(), &wall); |
| |
| if (idle_time != -1ULL) { |
| /* Idle micro accounting is supported. Use finer thresholds */ |
| dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; |
| dbs_tuners_ins.down_differential = |
| MICRO_FREQUENCY_DOWN_DIFFERENTIAL; |
| } |
| |
| kondemand_wq = create_workqueue("kondemand"); |
| if (!kondemand_wq) { |
| printk(KERN_ERR "Creation of kondemand failed\n"); |
| return -EFAULT; |
| } |
| err = cpufreq_register_governor(&cpufreq_gov_ondemand); |
| if (err) |
| destroy_workqueue(kondemand_wq); |
| |
| return err; |
| } |
| |
| static void __exit cpufreq_gov_dbs_exit(void) |
| { |
| cpufreq_unregister_governor(&cpufreq_gov_ondemand); |
| destroy_workqueue(kondemand_wq); |
| } |
| |
| |
| MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
| MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>"); |
| MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " |
| "Low Latency Frequency Transition capable processors"); |
| MODULE_LICENSE("GPL"); |
| |
| #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
| fs_initcall(cpufreq_gov_dbs_init); |
| #else |
| module_init(cpufreq_gov_dbs_init); |
| #endif |
| module_exit(cpufreq_gov_dbs_exit); |