| /* |
| * drivers/cpufreq/cpufreq_conservative.c |
| * |
| * Copyright (C) 2001 Russell King |
| * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. |
| * Jun Nakajima <jun.nakajima@intel.com> |
| * (C) 2009 Alexander Clouter <alex@digriz.org.uk> |
| * |
| * 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/cpufreq.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/kobject.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/notifier.h> |
| #include <linux/percpu-defs.h> |
| #include <linux/slab.h> |
| #include <linux/sysfs.h> |
| #include <linux/types.h> |
| |
| #include "cpufreq_governor.h" |
| |
| /* Conservative governor macros */ |
| #define DEF_FREQUENCY_UP_THRESHOLD (80) |
| #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
| #define DEF_FREQUENCY_STEP (5) |
| #define DEF_SAMPLING_DOWN_FACTOR (1) |
| #define MAX_SAMPLING_DOWN_FACTOR (10) |
| |
| static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); |
| |
| static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, |
| struct cpufreq_policy *policy) |
| { |
| unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100; |
| |
| /* max freq cannot be less than 100. But who knows... */ |
| if (unlikely(freq_target == 0)) |
| freq_target = DEF_FREQUENCY_STEP; |
| |
| return freq_target; |
| } |
| |
| /* |
| * 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 check, if current idle time is more than 80% |
| * (default), then we try to decrease frequency |
| * |
| * Any frequency increase takes it to the maximum frequency. Frequency reduction |
| * happens at minimum steps of 5% (default) of maximum frequency |
| */ |
| static void cs_check_cpu(int cpu, unsigned int load) |
| { |
| struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); |
| struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy; |
| struct dbs_data *dbs_data = policy->governor_data; |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int freq_target; |
| |
| /* |
| * break out if we 'cannot' reduce the speed as the user might |
| * want freq_step to be zero |
| */ |
| if (cs_tuners->freq_step == 0) |
| return; |
| |
| /* Check for frequency increase */ |
| if (load > cs_tuners->up_threshold) { |
| dbs_info->down_skip = 0; |
| |
| /* if we are already at full speed then break out early */ |
| if (dbs_info->requested_freq == policy->max) |
| return; |
| |
| dbs_info->requested_freq += get_freq_target(cs_tuners, policy); |
| if (dbs_info->requested_freq > policy->max) |
| dbs_info->requested_freq = policy->max; |
| |
| __cpufreq_driver_target(policy, dbs_info->requested_freq, |
| CPUFREQ_RELATION_H); |
| return; |
| } |
| |
| /* if sampling_down_factor is active break out early */ |
| if (++dbs_info->down_skip < cs_tuners->sampling_down_factor) |
| return; |
| dbs_info->down_skip = 0; |
| |
| /* Check for frequency decrease */ |
| if (load < cs_tuners->down_threshold) { |
| /* |
| * if we cannot reduce the frequency anymore, break out early |
| */ |
| if (policy->cur == policy->min) |
| return; |
| |
| freq_target = get_freq_target(cs_tuners, policy); |
| if (dbs_info->requested_freq > freq_target) { |
| dbs_info->requested_freq -= freq_target; |
| if (dbs_info->requested_freq < policy->min) |
| dbs_info->requested_freq = policy->min; |
| } else |
| dbs_info->requested_freq = policy->min; |
| |
| __cpufreq_driver_target(policy, dbs_info->requested_freq, |
| CPUFREQ_RELATION_L); |
| return; |
| } |
| } |
| |
| static void cs_dbs_timer(struct work_struct *work) |
| { |
| struct cs_cpu_dbs_info_s *dbs_info = container_of(work, |
| struct cs_cpu_dbs_info_s, cdbs.work.work); |
| unsigned int cpu = dbs_info->cdbs.cur_policy->cpu; |
| struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info, |
| cpu); |
| struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data; |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| int delay = delay_for_sampling_rate(cs_tuners->sampling_rate); |
| bool modify_all = true; |
| |
| mutex_lock(&core_dbs_info->cdbs.timer_mutex); |
| if (!need_load_eval(&core_dbs_info->cdbs, cs_tuners->sampling_rate)) |
| modify_all = false; |
| else |
| dbs_check_cpu(dbs_data, cpu); |
| |
| gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all); |
| mutex_unlock(&core_dbs_info->cdbs.timer_mutex); |
| } |
| |
| static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
| void *data) |
| { |
| struct cpufreq_freqs *freq = data; |
| struct cs_cpu_dbs_info_s *dbs_info = |
| &per_cpu(cs_cpu_dbs_info, freq->cpu); |
| struct cpufreq_policy *policy; |
| |
| if (!dbs_info->enable) |
| return 0; |
| |
| policy = dbs_info->cdbs.cur_policy; |
| |
| /* |
| * we only care if our internally tracked freq moves outside the 'valid' |
| * ranges of frequency available to us otherwise we do not change it |
| */ |
| if (dbs_info->requested_freq > policy->max |
| || dbs_info->requested_freq < policy->min) |
| dbs_info->requested_freq = freq->new; |
| |
| return 0; |
| } |
| |
| /************************** sysfs interface ************************/ |
| static struct common_dbs_data cs_dbs_cdata; |
| |
| static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, |
| const char *buf, size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
| return -EINVAL; |
| |
| cs_tuners->sampling_down_factor = input; |
| return count; |
| } |
| |
| static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf, |
| size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| if (ret != 1) |
| return -EINVAL; |
| |
| cs_tuners->sampling_rate = max(input, dbs_data->min_sampling_rate); |
| return count; |
| } |
| |
| static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf, |
| size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
| return -EINVAL; |
| |
| cs_tuners->up_threshold = input; |
| return count; |
| } |
| |
| static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf, |
| size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| /* cannot be lower than 11 otherwise freq will not fall */ |
| if (ret != 1 || input < 11 || input > 100 || |
| input >= cs_tuners->up_threshold) |
| return -EINVAL; |
| |
| cs_tuners->down_threshold = input; |
| return count; |
| } |
| |
| static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data, |
| const char *buf, size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input, j; |
| int ret; |
| |
| ret = sscanf(buf, "%u", &input); |
| if (ret != 1) |
| return -EINVAL; |
| |
| if (input > 1) |
| input = 1; |
| |
| if (input == cs_tuners->ignore_nice_load) /* nothing to do */ |
| return count; |
| |
| cs_tuners->ignore_nice_load = input; |
| |
| /* we need to re-evaluate prev_cpu_idle */ |
| for_each_online_cpu(j) { |
| struct cs_cpu_dbs_info_s *dbs_info; |
| dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
| dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j, |
| &dbs_info->cdbs.prev_cpu_wall, 0); |
| if (cs_tuners->ignore_nice_load) |
| dbs_info->cdbs.prev_cpu_nice = |
| kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
| } |
| return count; |
| } |
| |
| static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf, |
| size_t count) |
| { |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| if (ret != 1) |
| return -EINVAL; |
| |
| if (input > 100) |
| input = 100; |
| |
| /* |
| * no need to test here if freq_step is zero as the user might actually |
| * want this, they would be crazy though :) |
| */ |
| cs_tuners->freq_step = input; |
| return count; |
| } |
| |
| show_store_one(cs, sampling_rate); |
| show_store_one(cs, sampling_down_factor); |
| show_store_one(cs, up_threshold); |
| show_store_one(cs, down_threshold); |
| show_store_one(cs, ignore_nice_load); |
| show_store_one(cs, freq_step); |
| declare_show_sampling_rate_min(cs); |
| |
| gov_sys_pol_attr_rw(sampling_rate); |
| gov_sys_pol_attr_rw(sampling_down_factor); |
| gov_sys_pol_attr_rw(up_threshold); |
| gov_sys_pol_attr_rw(down_threshold); |
| gov_sys_pol_attr_rw(ignore_nice_load); |
| gov_sys_pol_attr_rw(freq_step); |
| gov_sys_pol_attr_ro(sampling_rate_min); |
| |
| static struct attribute *dbs_attributes_gov_sys[] = { |
| &sampling_rate_min_gov_sys.attr, |
| &sampling_rate_gov_sys.attr, |
| &sampling_down_factor_gov_sys.attr, |
| &up_threshold_gov_sys.attr, |
| &down_threshold_gov_sys.attr, |
| &ignore_nice_load_gov_sys.attr, |
| &freq_step_gov_sys.attr, |
| NULL |
| }; |
| |
| static struct attribute_group cs_attr_group_gov_sys = { |
| .attrs = dbs_attributes_gov_sys, |
| .name = "conservative", |
| }; |
| |
| static struct attribute *dbs_attributes_gov_pol[] = { |
| &sampling_rate_min_gov_pol.attr, |
| &sampling_rate_gov_pol.attr, |
| &sampling_down_factor_gov_pol.attr, |
| &up_threshold_gov_pol.attr, |
| &down_threshold_gov_pol.attr, |
| &ignore_nice_load_gov_pol.attr, |
| &freq_step_gov_pol.attr, |
| NULL |
| }; |
| |
| static struct attribute_group cs_attr_group_gov_pol = { |
| .attrs = dbs_attributes_gov_pol, |
| .name = "conservative", |
| }; |
| |
| /************************** sysfs end ************************/ |
| |
| static int cs_init(struct dbs_data *dbs_data) |
| { |
| struct cs_dbs_tuners *tuners; |
| |
| tuners = kzalloc(sizeof(struct cs_dbs_tuners), GFP_KERNEL); |
| if (!tuners) { |
| pr_err("%s: kzalloc failed\n", __func__); |
| return -ENOMEM; |
| } |
| |
| tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
| tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
| tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; |
| tuners->ignore_nice_load = 0; |
| tuners->freq_step = DEF_FREQUENCY_STEP; |
| |
| dbs_data->tuners = tuners; |
| dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * |
| jiffies_to_usecs(10); |
| mutex_init(&dbs_data->mutex); |
| return 0; |
| } |
| |
| static void cs_exit(struct dbs_data *dbs_data) |
| { |
| kfree(dbs_data->tuners); |
| } |
| |
| define_get_cpu_dbs_routines(cs_cpu_dbs_info); |
| |
| static struct notifier_block cs_cpufreq_notifier_block = { |
| .notifier_call = dbs_cpufreq_notifier, |
| }; |
| |
| static struct cs_ops cs_ops = { |
| .notifier_block = &cs_cpufreq_notifier_block, |
| }; |
| |
| static struct common_dbs_data cs_dbs_cdata = { |
| .governor = GOV_CONSERVATIVE, |
| .attr_group_gov_sys = &cs_attr_group_gov_sys, |
| .attr_group_gov_pol = &cs_attr_group_gov_pol, |
| .get_cpu_cdbs = get_cpu_cdbs, |
| .get_cpu_dbs_info_s = get_cpu_dbs_info_s, |
| .gov_dbs_timer = cs_dbs_timer, |
| .gov_check_cpu = cs_check_cpu, |
| .gov_ops = &cs_ops, |
| .init = cs_init, |
| .exit = cs_exit, |
| }; |
| |
| static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| unsigned int event) |
| { |
| return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event); |
| } |
| |
| #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
| static |
| #endif |
| struct cpufreq_governor cpufreq_gov_conservative = { |
| .name = "conservative", |
| .governor = cs_cpufreq_governor_dbs, |
| .max_transition_latency = TRANSITION_LATENCY_LIMIT, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int __init cpufreq_gov_dbs_init(void) |
| { |
| return cpufreq_register_governor(&cpufreq_gov_conservative); |
| } |
| |
| static void __exit cpufreq_gov_dbs_exit(void) |
| { |
| cpufreq_unregister_governor(&cpufreq_gov_conservative); |
| } |
| |
| MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
| MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
| "Low Latency Frequency Transition capable processors " |
| "optimised for use in a battery environment"); |
| MODULE_LICENSE("GPL"); |
| |
| #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
| fs_initcall(cpufreq_gov_dbs_init); |
| #else |
| module_init(cpufreq_gov_dbs_init); |
| #endif |
| module_exit(cpufreq_gov_dbs_exit); |