/* * drivers/cpufreq/cpufreq_conservative.c * * Copyright (C) 2001 Russell King * (C) 2003 Venkatesh Pallipadi . * Jun Nakajima * (C) 2009 Alexander Clouter * * 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 #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.policy_dbs->policy; struct policy_dbs_info *policy_dbs = policy->governor_data; struct dbs_data *dbs_data = policy_dbs->dbs_data; struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; /* * 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 > dbs_data->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 < dbs_data->sampling_down_factor) return; dbs_info->down_skip = 0; /* Check for frequency decrease */ if (load < cs_tuners->down_threshold) { unsigned int freq_target; /* * 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; else dbs_info->requested_freq = policy->min; __cpufreq_driver_target(policy, dbs_info->requested_freq, CPUFREQ_RELATION_L); return; } } static unsigned int cs_dbs_timer(struct cpufreq_policy *policy) { struct policy_dbs_info *policy_dbs = policy->governor_data; struct dbs_data *dbs_data = policy_dbs->dbs_data; dbs_check_cpu(policy); return delay_for_sampling_rate(dbs_data->sampling_rate); } static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data); static struct notifier_block cs_cpufreq_notifier_block = { .notifier_call = dbs_cpufreq_notifier, }; /************************** sysfs interface ************************/ static struct dbs_governor cs_dbs_gov; static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) return -EINVAL; dbs_data->sampling_down_factor = input; 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; dbs_data->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 >= dbs_data->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) { unsigned int input, j; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; if (input > 1) input = 1; if (input == dbs_data->ignore_nice_load) /* nothing to do */ return count; dbs_data->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 (dbs_data->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; } gov_show_one_common(sampling_rate); gov_show_one_common(sampling_down_factor); gov_show_one_common(up_threshold); gov_show_one_common(ignore_nice_load); gov_show_one_common(min_sampling_rate); gov_show_one(cs, down_threshold); gov_show_one(cs, freq_step); gov_attr_rw(sampling_rate); gov_attr_rw(sampling_down_factor); gov_attr_rw(up_threshold); gov_attr_rw(ignore_nice_load); gov_attr_ro(min_sampling_rate); gov_attr_rw(down_threshold); gov_attr_rw(freq_step); static struct attribute *cs_attributes[] = { &min_sampling_rate.attr, &sampling_rate.attr, &sampling_down_factor.attr, &up_threshold.attr, &down_threshold.attr, &ignore_nice_load.attr, &freq_step.attr, NULL }; /************************** sysfs end ************************/ static int cs_init(struct dbs_data *dbs_data, bool notify) { struct cs_dbs_tuners *tuners; tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); if (!tuners) { pr_err("%s: kzalloc failed\n", __func__); return -ENOMEM; } tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; tuners->freq_step = DEF_FREQUENCY_STEP; dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; dbs_data->ignore_nice_load = 0; dbs_data->tuners = tuners; dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); if (notify) cpufreq_register_notifier(&cs_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); return 0; } static void cs_exit(struct dbs_data *dbs_data, bool notify) { if (notify) cpufreq_unregister_notifier(&cs_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); kfree(dbs_data->tuners); } define_get_cpu_dbs_routines(cs_cpu_dbs_info); static struct dbs_governor cs_dbs_gov = { .gov = { .name = "conservative", .governor = cpufreq_governor_dbs, .max_transition_latency = TRANSITION_LATENCY_LIMIT, .owner = THIS_MODULE, }, .governor = GOV_CONSERVATIVE, .kobj_type = { .default_attrs = cs_attributes }, .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, .init = cs_init, .exit = cs_exit, }; #define CPU_FREQ_GOV_CONSERVATIVE (&cs_dbs_gov.gov) 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 = cpufreq_cpu_get_raw(freq->cpu); if (!policy) return 0; /* policy isn't governed by conservative governor */ if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE) return 0; /* * 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; } static int __init cpufreq_gov_dbs_init(void) { return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); } static void __exit cpufreq_gov_dbs_exit(void) { cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); } MODULE_AUTHOR("Alexander Clouter "); 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 struct cpufreq_governor *cpufreq_default_governor(void) { return CPU_FREQ_GOV_CONSERVATIVE; } fs_initcall(cpufreq_gov_dbs_init); #else module_init(cpufreq_gov_dbs_init); #endif module_exit(cpufreq_gov_dbs_exit);