/* * drivers/cpufreq/cpufreq_ondemand.c * * Copyright (C) 2001 Russell King * (C) 2003 Venkatesh Pallipadi . * Jun Nakajima * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include "cpufreq_governor.h" /* On-demand governor macors */ #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) #define DEF_FREQUENCY_UP_THRESHOLD (80) #define DEF_SAMPLING_DOWN_FACTOR (1) #define MAX_SAMPLING_DOWN_FACTOR (100000) #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) #define MICRO_FREQUENCY_UP_THRESHOLD (95) #define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000) #define MIN_FREQUENCY_UP_THRESHOLD (11) #define MAX_FREQUENCY_UP_THRESHOLD (100) static struct dbs_data od_dbs_data; static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info); #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND static struct cpufreq_governor cpufreq_gov_ondemand; #endif static struct od_dbs_tuners od_tuners = { .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, .ignore_nice = 0, .powersave_bias = 0, }; static void ondemand_powersave_bias_init_cpu(int cpu) { struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu); dbs_info->freq_table = cpufreq_frequency_get_table(cpu); dbs_info->freq_lo = 0; } /* * Not all CPUs want IO time to be accounted as busy; this depends on how * efficient idling at a higher frequency/voltage is. * Pavel Machek says this is not so for various generations of AMD and old * Intel systems. * Mike Chan (androidlcom) calis this is also not true for ARM. * Because of this, whitelist specific known (series) of CPUs by default, and * leave all others up to the user. */ static int should_io_be_busy(void) { #if defined(CONFIG_X86) /* * For Intel, Core 2 (model 15) andl later have an efficient idle. */ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model >= 15) return 1; #endif return 0; } /* * 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 od_cpu_dbs_info_s *dbs_info = &per_cpu(od_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 * od_tuners.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(od_tuners.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) { ondemand_powersave_bias_init_cpu(i); } } static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq) { if (od_tuners.powersave_bias) freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H); else if (p->cur == p->max) return; __cpufreq_driver_target(p, freq, od_tuners.powersave_bias ? CPUFREQ_RELATION_L : CPUFREQ_RELATION_H); } /* * 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 */ static void od_check_cpu(int cpu, unsigned int load_freq) { struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu); struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy; dbs_info->freq_lo = 0; /* Check for frequency increase */ if (load_freq > od_tuners.up_threshold * policy->cur) { /* If switching to max speed, apply sampling_down_factor */ if (policy->cur < policy->max) dbs_info->rate_mult = od_tuners.sampling_down_factor; dbs_freq_increase(policy, policy->max); 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 (load_freq < (od_tuners.up_threshold - od_tuners.down_differential) * policy->cur) { unsigned int freq_next; freq_next = load_freq / (od_tuners.up_threshold - od_tuners.down_differential); /* No longer fully busy, reset rate_mult */ dbs_info->rate_mult = 1; if (freq_next < policy->min) freq_next = policy->min; if (!od_tuners.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 od_dbs_timer(struct work_struct *work) { struct od_cpu_dbs_info_s *dbs_info = container_of(work, struct od_cpu_dbs_info_s, cdbs.work.work); unsigned int cpu = dbs_info->cdbs.cpu; int delay, sample_type = dbs_info->sample_type; mutex_lock(&dbs_info->cdbs.timer_mutex); /* Common NORMAL_SAMPLE setup */ dbs_info->sample_type = OD_NORMAL_SAMPLE; if (sample_type == OD_SUB_SAMPLE) { delay = dbs_info->freq_lo_jiffies; __cpufreq_driver_target(dbs_info->cdbs.cur_policy, dbs_info->freq_lo, CPUFREQ_RELATION_H); } else { dbs_check_cpu(&od_dbs_data, cpu); if (dbs_info->freq_lo) { /* Setup timer for SUB_SAMPLE */ dbs_info->sample_type = OD_SUB_SAMPLE; delay = dbs_info->freq_hi_jiffies; } else { delay = delay_for_sampling_rate(od_tuners.sampling_rate * dbs_info->rate_mult); } } schedule_delayed_work_on(smp_processor_id(), &dbs_info->cdbs.work, delay); mutex_unlock(&dbs_info->cdbs.timer_mutex); } /************************** sysfs interface ************************/ static ssize_t show_sampling_rate_min(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%u\n", od_dbs_data.min_sampling_rate); } /** * update_sampling_rate - update sampling rate effective immediately if needed. * @new_rate: new sampling rate * * If new rate is smaller than the old, simply updaing * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the * original sampling_rate was 1 second and the requested new sampling rate is 10 * ms because the user needs immediate reaction from ondemand governor, but not * sure if higher frequency will be required or not, then, the governor may * change the sampling rate too late; up to 1 second later. Thus, if we are * reducing the sampling rate, we need to make the new value effective * immediately. */ static void update_sampling_rate(unsigned int new_rate) { int cpu; od_tuners.sampling_rate = new_rate = max(new_rate, od_dbs_data.min_sampling_rate); for_each_online_cpu(cpu) { struct cpufreq_policy *policy; struct od_cpu_dbs_info_s *dbs_info; unsigned long next_sampling, appointed_at; policy = cpufreq_cpu_get(cpu); if (!policy) continue; if (policy->governor != &cpufreq_gov_ondemand) { cpufreq_cpu_put(policy); continue; } dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu); cpufreq_cpu_put(policy); mutex_lock(&dbs_info->cdbs.timer_mutex); if (!delayed_work_pending(&dbs_info->cdbs.work)) { mutex_unlock(&dbs_info->cdbs.timer_mutex); continue; } next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->cdbs.work.timer.expires; if (time_before(next_sampling, appointed_at)) { mutex_unlock(&dbs_info->cdbs.timer_mutex); cancel_delayed_work_sync(&dbs_info->cdbs.work); mutex_lock(&dbs_info->cdbs.timer_mutex); schedule_delayed_work_on(dbs_info->cdbs.cpu, &dbs_info->cdbs.work, usecs_to_jiffies(new_rate)); } mutex_unlock(&dbs_info->cdbs.timer_mutex); } } static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; update_sampling_rate(input); return count; } static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; od_tuners.io_is_busy = !!input; return count; } static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { return -EINVAL; } od_tuners.up_threshold = input; return count; } static ssize_t store_sampling_down_factor(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input, j; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) return -EINVAL; od_tuners.sampling_down_factor = input; /* Reset down sampling multiplier in case it was active */ for_each_online_cpu(j) { struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, j); dbs_info->rate_mult = 1; } return count; } static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, 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; if (input == od_tuners.ignore_nice) { /* nothing to do */ return count; } od_tuners.ignore_nice = input; /* we need to re-evaluate prev_cpu_idle */ for_each_online_cpu(j) { struct od_cpu_dbs_info_s *dbs_info; dbs_info = &per_cpu(od_cpu_dbs_info, j); dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j, &dbs_info->cdbs.prev_cpu_wall); if (od_tuners.ignore_nice) dbs_info->cdbs.prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; } return count; } static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b, 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; od_tuners.powersave_bias = input; ondemand_powersave_bias_init(); return count; } show_one(od, sampling_rate, sampling_rate); show_one(od, io_is_busy, io_is_busy); show_one(od, up_threshold, up_threshold); show_one(od, sampling_down_factor, sampling_down_factor); show_one(od, ignore_nice_load, ignore_nice); show_one(od, powersave_bias, powersave_bias); define_one_global_rw(sampling_rate); define_one_global_rw(io_is_busy); define_one_global_rw(up_threshold); define_one_global_rw(sampling_down_factor); define_one_global_rw(ignore_nice_load); define_one_global_rw(powersave_bias); define_one_global_ro(sampling_rate_min); static struct attribute *dbs_attributes[] = { &sampling_rate_min.attr, &sampling_rate.attr, &up_threshold.attr, &sampling_down_factor.attr, &ignore_nice_load.attr, &powersave_bias.attr, &io_is_busy.attr, NULL }; static struct attribute_group od_attr_group = { .attrs = dbs_attributes, .name = "ondemand", }; /************************** sysfs end ************************/ define_get_cpu_dbs_routines(od_cpu_dbs_info); static struct od_ops od_ops = { .io_busy = should_io_be_busy, .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu, .powersave_bias_target = powersave_bias_target, .freq_increase = dbs_freq_increase, }; static struct dbs_data od_dbs_data = { .governor = GOV_ONDEMAND, .attr_group = &od_attr_group, .tuners = &od_tuners, .get_cpu_cdbs = get_cpu_cdbs, .get_cpu_dbs_info_s = get_cpu_dbs_info_s, .gov_dbs_timer = od_dbs_timer, .gov_check_cpu = od_check_cpu, .gov_ops = &od_ops, }; static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event) { return cpufreq_governor_dbs(&od_dbs_data, policy, event); } #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND static #endif struct cpufreq_governor cpufreq_gov_ondemand = { .name = "ondemand", .governor = od_cpufreq_governor_dbs, .max_transition_latency = TRANSITION_LATENCY_LIMIT, .owner = THIS_MODULE, }; static int __init cpufreq_gov_dbs_init(void) { u64 idle_time; int cpu = get_cpu(); mutex_init(&od_dbs_data.mutex); idle_time = get_cpu_idle_time_us(cpu, NULL); put_cpu(); if (idle_time != -1ULL) { /* Idle micro accounting is supported. Use finer thresholds */ od_tuners.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; od_tuners.down_differential = MICRO_FREQUENCY_DOWN_DIFFERENTIAL; /* * In nohz/micro accounting case we set the minimum frequency * not depending on HZ, but fixed (very low). The deferred * timer might skip some samples if idle/sleeping as needed. */ od_dbs_data.min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE; } else { /* For correct statistics, we need 10 ticks for each measure */ od_dbs_data.min_sampling_rate = MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); } return cpufreq_register_governor(&cpufreq_gov_ondemand); } static void __exit cpufreq_gov_dbs_exit(void) { cpufreq_unregister_governor(&cpufreq_gov_ondemand); } 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"); #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);