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Diffstat (limited to 'drivers/cpufreq/cpufreq_conservative.c')
-rw-r--r--drivers/cpufreq/cpufreq_conservative.c414
1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
new file mode 100644
index 000000000..9a76965fa
--- /dev/null
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -0,0 +1,414 @@
+/*
+ * 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"
+
+/* Conservative governor macros */
+#ifdef CONFIG_SCHED_BFS
+#define DEF_FREQUENCY_UP_THRESHOLD (63)
+#define DEF_FREQUENCY_DOWN_THRESHOLD (26)
+#else
+#define DEF_FREQUENCY_UP_THRESHOLD (80)
+#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
+#endif
+
+#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;
+
+ /*
+ * 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) {
+ 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 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(*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);