--- /dev/null
+/*
+ * Copyright (c) 2012 NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpuquiet.h>
+#include <linux/cpumask.h>
+#include <linux/module.h>
+#include <linux/cpufreq.h>
+#include <linux/pm_qos_params.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <asm/cputime.h>
+
+#define CPUNAMELEN 8
+
+typedef enum {
+ CPU_SPEED_BALANCED,
+ CPU_SPEED_BIASED,
+ CPU_SPEED_SKEWED,
+} CPU_SPEED_BALANCE;
+
+typedef enum {
+ IDLE,
+ DOWN,
+ UP,
+} BALANCED_STATE;
+
+struct idle_info {
+ u64 idle_last;
+ u64 last_timestamp;
+ u64 idle_current;
+ u64 timestamp;
+};
+
+static DEFINE_PER_CPU(struct idle_info, idleinfo);
+static DEFINE_PER_CPU(unsigned int, cpu_load);
+
+static struct timer_list load_timer;
+static bool load_timer_active;
+struct balanced_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct balanced_attribute *attr, char *buf);
+ ssize_t (*store)(struct balanced_attribute *attr, const char *buf,
+ size_t count);
+ unsigned long *param;
+};
+
+#define BALANCED_ATTRIBUTE(_name, _mode) \
+ static struct balanced_attribute _name ## _attr = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .show = show_attribute, \
+ .store = store_attribute, \
+ .param = &_name, \
+}
+
+/* configurable parameters */
+static unsigned long balance_level = 75;
+static unsigned long idle_bottom_freq;
+static unsigned long idle_top_freq;
+static unsigned long up_delay;
+static unsigned long down_delay;
+
+static struct workqueue_struct *balanced_wq;
+static struct delayed_work balanced_work;
+static BALANCED_STATE balanced_state;
+static struct kobject *balanced_kobject;
+
+static void calculate_load_timer(unsigned long data)
+{
+ int i;
+ u64 idle_time, elapsed_time;
+
+ if (!load_timer_active)
+ return;
+
+ for_each_online_cpu(i) {
+ struct idle_info *iinfo = &per_cpu(idleinfo, i);
+ unsigned int *load = &per_cpu(cpu_load, i);
+
+ iinfo->idle_last = iinfo->idle_current;
+ iinfo->last_timestamp = iinfo->timestamp;
+ iinfo->idle_current =
+ get_cpu_idle_time_us(i, &iinfo->timestamp);
+ elapsed_time = iinfo->timestamp - iinfo->last_timestamp;
+
+ idle_time = iinfo->idle_current - iinfo->idle_last;
+ idle_time *= 100;
+ do_div(idle_time, elapsed_time);
+ *load = 100 - idle_time;
+ }
+ mod_timer(&load_timer, jiffies + msecs_to_jiffies(100));
+}
+
+static void start_load_timer(void)
+{
+ int i;
+
+ if (load_timer_active)
+ return;
+
+ load_timer_active = true;
+
+ for_each_online_cpu(i) {
+ struct idle_info *iinfo = &per_cpu(idleinfo, i);
+
+ iinfo->idle_current =
+ get_cpu_idle_time_us(i, &iinfo->timestamp);
+ }
+ mod_timer(&load_timer, jiffies + msecs_to_jiffies(100));
+}
+
+static void stop_load_timer(void)
+{
+ if (!load_timer_active)
+ return;
+
+ load_timer_active = false;
+ del_timer(&load_timer);
+}
+
+static unsigned int get_slowest_cpu_n(void)
+{
+ unsigned int cpu = nr_cpu_ids;
+ unsigned long minload = ULONG_MAX;
+ int i;
+
+ for_each_online_cpu(i) {
+ unsigned int *load = &per_cpu(cpu_load, i);
+
+ if ((i > 0) && (minload > *load)) {
+ cpu = i;
+ minload = *load;
+ }
+ }
+
+ return cpu;
+}
+
+static unsigned int cpu_highest_speed(void)
+{
+ unsigned int maxload = 0;
+ int i;
+
+ for_each_online_cpu(i) {
+ unsigned int *load = &per_cpu(cpu_load, i);
+
+ maxload = max(maxload, *load);
+ }
+
+ return maxload;
+}
+
+static unsigned int count_slow_cpus(unsigned int limit)
+{
+ unsigned int cnt = 0;
+ int i;
+
+ for_each_online_cpu(i) {
+ unsigned int *load = &per_cpu(cpu_load, i);
+
+ if (*load <= limit)
+ cnt++;
+ }
+
+ return cnt;
+}
+
+static CPU_SPEED_BALANCE balanced_speed_balance(void)
+{
+ unsigned long highest_speed = cpu_highest_speed();
+ unsigned long balanced_speed = highest_speed * balance_level / 100;
+ unsigned long skewed_speed = balanced_speed / 2;
+ unsigned int nr_cpus = num_online_cpus();
+ unsigned int max_cpus = pm_qos_request(PM_QOS_MAX_ONLINE_CPUS) ? : 4;
+
+ /* balanced: freq targets for all CPUs are above 50% of highest speed
+ biased: freq target for at least one CPU is below 50% threshold
+ skewed: freq targets for at least 2 CPUs are below 25% threshold */
+ if (count_slow_cpus(skewed_speed) >= 2 || nr_cpus > max_cpus)
+ return CPU_SPEED_SKEWED;
+
+ if (count_slow_cpus(balanced_speed) >= 1 || nr_cpus == max_cpus)
+ return CPU_SPEED_BIASED;
+
+ return CPU_SPEED_BALANCED;
+}
+
+static void balanced_work_func(struct work_struct *work)
+{
+ bool up = false;
+ unsigned int cpu = nr_cpu_ids;
+ CPU_SPEED_BALANCE balance;
+
+ switch (balanced_state) {
+ case IDLE:
+ break;
+ case DOWN:
+ cpu = get_slowest_cpu_n();
+ if (cpu < nr_cpu_ids) {
+ up = false;
+ queue_delayed_work(balanced_wq,
+ &balanced_work, down_delay);
+ } else
+ stop_load_timer();
+ break;
+ case UP:
+ balance = balanced_speed_balance();
+ switch (balance) {
+
+ /* cpu speed is up and balanced - one more on-line */
+ case CPU_SPEED_BALANCED:
+ cpu = cpumask_next_zero(0, cpu_online_mask);
+ if (cpu < nr_cpu_ids)
+ up = true;
+ break;
+ /* cpu speed is up, but skewed - remove one core */
+ case CPU_SPEED_SKEWED:
+ cpu = get_slowest_cpu_n();
+ if (cpu < nr_cpu_ids)
+ up = false;
+ break;
+ /* cpu speed is up, but under-utilized - do nothing */
+ case CPU_SPEED_BIASED:
+ default:
+ break;
+ }
+ queue_delayed_work(
+ balanced_wq, &balanced_work, up_delay);
+ break;
+ default:
+ pr_err("%s: invalid cpuquiet balanced governor state %d\n",
+ __func__, balanced_state);
+ }
+
+ if (cpu < nr_cpu_ids) {
+ if (up)
+ cpuquiet_wake_cpu(cpu);
+ else
+ cpuquiet_quiesence_cpu(cpu);
+ }
+}
+
+static int balanced_cpufreq_transition(struct notifier_block *nb,
+ unsigned long state, void *data)
+{
+ struct cpufreq_freqs *freqs = data;
+ unsigned long cpu_freq;
+
+ if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE) {
+ cpu_freq = freqs->new;
+
+ switch (balanced_state) {
+ case IDLE:
+ if (cpu_freq > idle_top_freq) {
+ balanced_state = UP;
+ queue_delayed_work(
+ balanced_wq, &balanced_work, up_delay);
+ start_load_timer();
+ } else if (cpu_freq <= idle_bottom_freq) {
+ balanced_state = DOWN;
+ queue_delayed_work(
+ balanced_wq, &balanced_work,
+ down_delay);
+ start_load_timer();
+ }
+ break;
+ case DOWN:
+ if (cpu_freq > idle_top_freq) {
+ balanced_state = UP;
+ queue_delayed_work(
+ balanced_wq, &balanced_work, up_delay);
+ start_load_timer();
+ }
+ break;
+ case UP:
+ if (cpu_freq <= idle_bottom_freq) {
+ balanced_state = DOWN;
+ queue_delayed_work(balanced_wq,
+ &balanced_work, down_delay);
+ start_load_timer();
+ }
+ break;
+ default:
+ pr_err("%s: invalid tegra hotplug state %d\n",
+ __func__, balanced_state);
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block balanced_cpufreq_nb = {
+ .notifier_call = balanced_cpufreq_transition,
+};
+
+static ssize_t show_attribute(struct balanced_attribute *battr, char *buf)
+{
+ return sprintf(buf, "%lu\n", *(battr->param));
+}
+
+static ssize_t store_attribute(struct balanced_attribute *battr,
+ const char *buf, size_t count)
+{
+ int err;
+ unsigned long val;
+
+ err = strict_strtoul(buf, 0, &val);
+ if (err < 0)
+ return err;
+
+ *(battr->param) = val;
+
+ return count;
+}
+
+static ssize_t balanced_sysfs_store(struct kobject *kobj,
+ struct attribute *attr, const char *buf, size_t count)
+{
+ struct balanced_attribute *battr =
+ container_of(attr, struct balanced_attribute, attr);
+
+ if (battr->store)
+ return battr->store(battr, buf, count);
+
+ return -EINVAL;
+}
+
+static ssize_t balanced_sysfs_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct balanced_attribute *battr =
+ container_of(attr, struct balanced_attribute, attr);
+
+ return battr->show(battr, buf);
+}
+
+BALANCED_ATTRIBUTE(balance_level, 0644);
+BALANCED_ATTRIBUTE(idle_bottom_freq, 0644);
+BALANCED_ATTRIBUTE(idle_top_freq, 0644);
+BALANCED_ATTRIBUTE(up_delay, 0644);
+BALANCED_ATTRIBUTE(down_delay, 0644);
+
+static struct attribute *balanced_attributes[] = {
+ &balance_level_attr.attr,
+ &idle_bottom_freq_attr.attr,
+ &idle_top_freq_attr.attr,
+ &up_delay_attr.attr,
+ &down_delay_attr.attr,
+ NULL,
+};
+
+static const struct sysfs_ops balanced_sysfs_ops = {
+ .show = balanced_sysfs_show,
+ .store = balanced_sysfs_store,
+};
+
+static struct kobj_type ktype_balanced = {
+ .sysfs_ops = &balanced_sysfs_ops,
+ .default_attrs = balanced_attributes,
+};
+
+static int balanced_sysfs(void)
+{
+ int err;
+
+ balanced_kobject = kzalloc(sizeof(*balanced_kobject),
+ GFP_KERNEL);
+
+ if (!balanced_kobject)
+ return -ENOMEM;
+
+ err = cpuquiet_kobject_init(balanced_kobject, &ktype_balanced,
+ "balanced");
+
+ if (err)
+ kfree(balanced_kobject);
+
+ return err;
+}
+
+static void balanced_stop(void)
+{
+
+ /*
+ first unregister the notifiers. This ensures the governor state
+ can't be modified by a cpufreq transition
+ */
+ cpufreq_unregister_notifier(&balanced_cpufreq_nb,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ /* now we can force the governor to be idle */
+ balanced_state = IDLE;
+ cancel_delayed_work_sync(&balanced_work);
+ destroy_workqueue(balanced_wq);
+ del_timer(&load_timer);
+
+ kobject_put(balanced_kobject);
+}
+
+static int balanced_start(void)
+{
+ int err, count;
+ struct cpufreq_frequency_table *table;
+
+ err = balanced_sysfs();
+ if (err)
+ return err;
+
+ balanced_wq = alloc_workqueue("cpuquiet-balanced",
+ WQ_UNBOUND | WQ_RESCUER | WQ_FREEZABLE, 1);
+ if (!balanced_wq)
+ return -ENOMEM;
+
+ INIT_DELAYED_WORK(&balanced_work, balanced_work_func);
+
+ up_delay = msecs_to_jiffies(1000);
+ down_delay = msecs_to_jiffies(2000);
+
+ table = cpufreq_frequency_get_table(0);
+ for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
+ ;
+
+ idle_top_freq = table[(count / 2) - 1].frequency;
+ idle_bottom_freq = table[(count / 2) - 2].frequency;
+
+ cpufreq_register_notifier(&balanced_cpufreq_nb,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ init_timer(&load_timer);
+ load_timer.function = calculate_load_timer;
+
+ return 0;
+}
+
+struct cpuquiet_governor balanced_governor = {
+ .name = "balanced",
+ .start = balanced_start,
+ .stop = balanced_stop,
+ .owner = THIS_MODULE,
+};
+
+static int __init init_balanced(void)
+{
+ return cpuquiet_register_governor(&balanced_governor);
+}
+
+static void __exit exit_balanced(void)
+{
+ cpuquiet_unregister_governor(&balanced_governor);
+}
+
+MODULE_LICENSE("GPL");
+module_init(init_balanced);
+module_exit(exit_balanced);
+
projects / firefly-linux-kernel-4.4.55.git / commitdiff