| /* |
| * 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/slab.h> |
| #include "cpufreq_governor.h" |
| |
| struct cs_policy_dbs_info { |
| struct policy_dbs_info policy_dbs; |
| unsigned int down_skip; |
| unsigned int requested_freq; |
| }; |
| |
| static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs) |
| { |
| return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs); |
| } |
| |
| struct cs_dbs_tuners { |
| unsigned int down_threshold; |
| unsigned int freq_step; |
| }; |
| |
| /* 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 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 unsigned int cs_dbs_timer(struct cpufreq_policy *policy) |
| { |
| struct policy_dbs_info *policy_dbs = policy->governor_data; |
| struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
| unsigned int requested_freq = dbs_info->requested_freq; |
| struct dbs_data *dbs_data = policy_dbs->dbs_data; |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int load = dbs_update(policy); |
| |
| /* |
| * break out if we 'cannot' reduce the speed as the user might |
| * want freq_step to be zero |
| */ |
| if (cs_tuners->freq_step == 0) |
| goto out; |
| |
| /* |
| * If requested_freq is out of range, it is likely that the limits |
| * changed in the meantime, so fall back to current frequency in that |
| * case. |
| */ |
| if (requested_freq > policy->max || requested_freq < policy->min) |
| requested_freq = policy->cur; |
| |
| /* 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 (requested_freq == policy->max) |
| goto out; |
| |
| requested_freq += get_freq_target(cs_tuners, policy); |
| if (requested_freq > policy->max) |
| requested_freq = policy->max; |
| |
| __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H); |
| dbs_info->requested_freq = requested_freq; |
| goto out; |
| } |
| |
| /* if sampling_down_factor is active break out early */ |
| if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
| goto out; |
| 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 (requested_freq == policy->min) |
| goto out; |
| |
| freq_target = get_freq_target(cs_tuners, policy); |
| if (requested_freq > freq_target) |
| requested_freq -= freq_target; |
| else |
| requested_freq = policy->min; |
| |
| __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L); |
| dbs_info->requested_freq = requested_freq; |
| } |
| |
| out: |
| return dbs_data->sampling_rate; |
| } |
| |
| /************************** sysfs interface ************************/ |
| |
| static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set, |
| const char *buf, size_t count) |
| { |
| struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| 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 gov_attr_set *attr_set, |
| const char *buf, size_t count) |
| { |
| struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| 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 gov_attr_set *attr_set, |
| const char *buf, size_t count) |
| { |
| struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
| unsigned int input; |
| int ret; |
| ret = sscanf(buf, "%u", &input); |
| |
| /* cannot be lower than 1 otherwise freq will not fall */ |
| if (ret != 1 || input < 1 || input > 100 || |
| input >= dbs_data->up_threshold) |
| return -EINVAL; |
| |
| cs_tuners->down_threshold = input; |
| return count; |
| } |
| |
| static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set, |
| const char *buf, size_t count) |
| { |
| struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| unsigned int input; |
| 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 */ |
| gov_update_cpu_data(dbs_data); |
| |
| return count; |
| } |
| |
| static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf, |
| size_t count) |
| { |
| struct dbs_data *dbs_data = to_dbs_data(attr_set); |
| 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 struct policy_dbs_info *cs_alloc(void) |
| { |
| struct cs_policy_dbs_info *dbs_info; |
| |
| dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); |
| return dbs_info ? &dbs_info->policy_dbs : NULL; |
| } |
| |
| static void cs_free(struct policy_dbs_info *policy_dbs) |
| { |
| kfree(to_dbs_info(policy_dbs)); |
| } |
| |
| static int cs_init(struct dbs_data *dbs_data) |
| { |
| struct cs_dbs_tuners *tuners; |
| |
| tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
| if (!tuners) |
| 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); |
| |
| return 0; |
| } |
| |
| static void cs_exit(struct dbs_data *dbs_data) |
| { |
| kfree(dbs_data->tuners); |
| } |
| |
| static void cs_start(struct cpufreq_policy *policy) |
| { |
| struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
| |
| dbs_info->down_skip = 0; |
| dbs_info->requested_freq = policy->cur; |
| } |
| |
| #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
| static |
| #endif |
| struct dbs_governor cs_governor = { |
| .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"), |
| .kobj_type = { .default_attrs = cs_attributes }, |
| .gov_dbs_timer = cs_dbs_timer, |
| .alloc = cs_alloc, |
| .free = cs_free, |
| .init = cs_init, |
| .exit = cs_exit, |
| .start = cs_start, |
| }; |
| |
| #define CPU_FREQ_GOV_CONSERVATIVE (&cs_governor.gov) |
| |
| 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 <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 |
| 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); |