===================================================================
@@ -107,6 +107,16 @@ config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
Be aware that not all cpufreq drivers support the conservative
governor. If unsure have a look at the help section of the
driver. Fallback governor will be the performance governor.
+
+config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
+ bool "schedutil"
+ select CPU_FREQ_GOV_SCHEDUTIL
+ select CPU_FREQ_GOV_PERFORMANCE
+ help
+ Use the 'schedutil' CPUFreq governor by default. If unsure,
+ have a look at the help section of that governor. The fallback
+ governor will be 'performance'.
+
endchoice
config CPU_FREQ_GOV_PERFORMANCE
@@ -188,6 +198,22 @@ config CPU_FREQ_GOV_CONSERVATIVE
If in doubt, say N.
+config CPU_FREQ_GOV_SCHEDUTIL
+ tristate "'schedutil' cpufreq policy governor"
+ depends on CPU_FREQ
+ select CPU_FREQ_GOV_ATTR_SET
+ select IRQ_WORK
+ help
+ The frequency selection formula used by this governor is analogous
+ to the one used by 'ondemand', but instead of computing CPU load
+ as the "non-idle CPU time" to "total CPU time" ratio, it uses CPU
+ utilization data provided by the scheduler as input.
+
+ To compile this driver as a module, choose M here: the
+ module will be called cpufreq_schedutil.
+
+ If in doubt, say N.
+
comment "CPU frequency scaling drivers"
config CPUFREQ_DT
===================================================================
@@ -0,0 +1,487 @@
+/*
+ * CPUFreq governor based on scheduler-provided CPU utilization data.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * 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/module.h>
+
+#include "sched.h"
+
+struct sugov_tunables {
+ struct gov_attr_set attr_set;
+ unsigned int rate_limit_us;
+};
+
+struct sugov_policy {
+ struct cpufreq_policy *policy;
+
+ struct sugov_tunables *tunables;
+ struct list_head tunables_hook;
+
+ raw_spinlock_t update_lock; /* For shared policies */
+ u64 last_freq_update_time;
+ s64 freq_update_delay_ns;
+ unsigned int next_freq;
+
+ /* The next fields are only needed if fast switch cannot be used. */
+ struct irq_work irq_work;
+ struct work_struct work;
+ struct mutex work_lock;
+ bool work_in_progress;
+
+ bool need_freq_update;
+};
+
+struct sugov_cpu {
+ struct freq_update_hook update_hook;
+ struct sugov_policy *sg_policy;
+
+ /* The fields below are only needed when sharing a policy. */
+ unsigned long util;
+ unsigned long max;
+ u64 last_update;
+};
+
+static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
+
+/************************ Governor internals ***********************/
+
+static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
+{
+ u64 delta_ns;
+
+ if (sg_policy->work_in_progress)
+ return false;
+
+ if (unlikely(sg_policy->need_freq_update)) {
+ sg_policy->need_freq_update = false;
+ return true;
+ }
+
+ delta_ns = time - sg_policy->last_freq_update_time;
+ return (s64)delta_ns >= sg_policy->freq_update_delay_ns;
+}
+
+static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
+ unsigned int next_freq)
+{
+ struct cpufreq_policy *policy = sg_policy->policy;
+
+ if (next_freq > policy->max)
+ next_freq = policy->max;
+ else if (next_freq < policy->min)
+ next_freq = policy->min;
+
+ sg_policy->last_freq_update_time = time;
+ if (sg_policy->next_freq == next_freq)
+ return;
+
+ sg_policy->next_freq = next_freq;
+ if (policy->fast_switch_possible) {
+ cpufreq_driver_fast_switch(policy, next_freq, CPUFREQ_RELATION_L);
+ } else {
+ sg_policy->work_in_progress = true;
+ irq_work_queue(&sg_policy->irq_work);
+ }
+}
+
+static void sugov_update_single(struct freq_update_hook *hook, u64 time,
+ unsigned long util, unsigned long max)
+{
+ struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_hook);
+ struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ unsigned int max_f, next_f;
+
+ if (!sugov_should_update_freq(sg_policy, time))
+ return;
+
+ max_f = sg_policy->policy->cpuinfo.max_freq;
+ next_f = util > max ? max_f : util * max_f / max;
+ sugov_update_commit(sg_policy, time, next_f);
+}
+
+static unsigned int sugov_next_freq(struct sugov_policy *sg_policy,
+ unsigned long util, unsigned long max)
+{
+ struct cpufreq_policy *policy = sg_policy->policy;
+ unsigned int max_f = policy->cpuinfo.max_freq;
+ u64 last_freq_update_time = sg_policy->last_freq_update_time;
+ unsigned int j;
+
+ if (util > max)
+ return max_f;
+
+ for_each_cpu(j, policy->cpus) {
+ struct sugov_cpu *j_sg_cpu;
+ unsigned long j_util, j_max;
+ u64 delta_ns;
+
+ if (j == smp_processor_id())
+ continue;
+
+ j_sg_cpu = &per_cpu(sugov_cpu, j);
+ /*
+ * If the CPU utilization was last updated before the previous
+ * frequency update and the time elapsed between the last update
+ * of the CPU utilization and the last frequency update is long
+ * enough, don't take the CPU into account as it probably is
+ * idle now.
+ */
+ delta_ns = last_freq_update_time - j_sg_cpu->last_update;
+ if ((s64)delta_ns > NSEC_PER_SEC / HZ)
+ continue;
+
+ j_util = j_sg_cpu->util;
+ j_max = j_sg_cpu->max;
+ if (j_util > j_max)
+ return max_f;
+
+ if (j_util * max > j_max * util) {
+ util = j_util;
+ max = j_max;
+ }
+ }
+
+ return util * max_f / max;
+}
+
+static void sugov_update_shared(struct freq_update_hook *hook, u64 time,
+ unsigned long util, unsigned long max)
+{
+ struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_hook);
+ struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ unsigned int next_f;
+
+ raw_spin_lock(&sg_policy->update_lock);
+
+ sg_cpu->util = util;
+ sg_cpu->max = max;
+ sg_cpu->last_update = time;
+
+ if (sugov_should_update_freq(sg_policy, time)) {
+ next_f = sugov_next_freq(sg_policy, util, max);
+ sugov_update_commit(sg_policy, time, next_f);
+ }
+
+ raw_spin_unlock(&sg_policy->update_lock);
+}
+
+static void sugov_work(struct work_struct *work)
+{
+ struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
+
+ mutex_lock(&sg_policy->work_lock);
+ __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq,
+ CPUFREQ_RELATION_L);
+ mutex_unlock(&sg_policy->work_lock);
+
+ sg_policy->work_in_progress = false;
+}
+
+static void sugov_irq_work(struct irq_work *irq_work)
+{
+ struct sugov_policy *sg_policy;
+
+ sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
+ schedule_work(&sg_policy->work);
+}
+
+/************************** sysfs interface ************************/
+
+static struct sugov_tunables *global_tunables;
+static DEFINE_MUTEX(global_tunables_lock);
+
+static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
+{
+ return container_of(attr_set, struct sugov_tunables, attr_set);
+}
+
+static ssize_t rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
+{
+ struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+
+ return sprintf(buf, "%u\n", tunables->rate_limit_us);
+}
+
+static ssize_t rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf,
+ size_t count)
+{
+ struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
+ struct sugov_policy *sg_policy;
+ unsigned int rate_limit_us;
+ int ret;
+
+ ret = sscanf(buf, "%u", &rate_limit_us);
+ if (ret != 1)
+ return -EINVAL;
+
+ tunables->rate_limit_us = rate_limit_us;
+
+ list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook)
+ sg_policy->freq_update_delay_ns = rate_limit_us * NSEC_PER_USEC;
+
+ return count;
+}
+
+static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us);
+
+static struct attribute *sugov_attributes[] = {
+ &rate_limit_us.attr,
+ NULL
+};
+
+static struct kobj_type sugov_tunables_ktype = {
+ .default_attrs = sugov_attributes,
+ .sysfs_ops = &governor_sysfs_ops,
+};
+
+/********************** cpufreq governor interface *********************/
+
+static struct cpufreq_governor schedutil_gov;
+
+static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy;
+
+ sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
+ if (!sg_policy)
+ return NULL;
+
+ sg_policy->policy = policy;
+ init_irq_work(&sg_policy->irq_work, sugov_irq_work);
+ INIT_WORK(&sg_policy->work, sugov_work);
+ mutex_init(&sg_policy->work_lock);
+ raw_spin_lock_init(&sg_policy->update_lock);
+ return sg_policy;
+}
+
+static void sugov_policy_free(struct sugov_policy *sg_policy)
+{
+ mutex_destroy(&sg_policy->work_lock);
+ kfree(sg_policy);
+}
+
+static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
+{
+ struct sugov_tunables *tunables;
+
+ tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
+ if (tunables)
+ gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
+
+ return tunables;
+}
+
+static void sugov_tunables_free(struct sugov_tunables *tunables)
+{
+ if (!have_governor_per_policy())
+ global_tunables = NULL;
+
+ kfree(tunables);
+}
+
+static int sugov_init(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy;
+ struct sugov_tunables *tunables;
+ unsigned int lat;
+ int ret = 0;
+
+ /* State should be equivalent to EXIT */
+ if (policy->governor_data)
+ return -EBUSY;
+
+ sg_policy = sugov_policy_alloc(policy);
+ if (!sg_policy)
+ return -ENOMEM;
+
+ mutex_lock(&global_tunables_lock);
+
+ if (global_tunables) {
+ if (WARN_ON(have_governor_per_policy())) {
+ ret = -EINVAL;
+ goto free_sg_policy;
+ }
+ policy->governor_data = sg_policy;
+ sg_policy->tunables = global_tunables;
+
+ gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
+ goto out;
+ }
+
+ tunables = sugov_tunables_alloc(sg_policy);
+ if (!tunables) {
+ ret = -ENOMEM;
+ goto free_sg_policy;
+ }
+
+ tunables->rate_limit_us = LATENCY_MULTIPLIER;
+ lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
+ if (lat)
+ tunables->rate_limit_us *= lat;
+
+ if (!have_governor_per_policy())
+ global_tunables = tunables;
+
+ policy->governor_data = sg_policy;
+ sg_policy->tunables = tunables;
+
+ ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
+ get_governor_parent_kobj(policy), "%s",
+ schedutil_gov.name);
+ if (!ret)
+ goto out;
+
+ /* Failure, so roll back. */
+ policy->governor_data = NULL;
+ sugov_tunables_free(tunables);
+
+ free_sg_policy:
+ pr_err("cpufreq: schedutil governor initialization failed (error %d)\n", ret);
+ sugov_policy_free(sg_policy);
+
+ out:
+ mutex_unlock(&global_tunables_lock);
+ return ret;
+}
+
+static int sugov_exit(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+ struct sugov_tunables *tunables = sg_policy->tunables;
+ unsigned int count;
+
+ mutex_lock(&global_tunables_lock);
+
+ count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
+ policy->governor_data = NULL;
+ if (!count)
+ sugov_tunables_free(tunables);
+
+ mutex_unlock(&global_tunables_lock);
+
+ sugov_policy_free(sg_policy);
+ return 0;
+}
+
+static int sugov_start(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+ unsigned int cpu;
+
+ sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
+ sg_policy->last_freq_update_time = 0;
+ sg_policy->next_freq = UINT_MAX;
+ sg_policy->work_in_progress = false;
+ sg_policy->need_freq_update = false;
+
+ for_each_cpu(cpu, policy->cpus) {
+ struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
+
+ sg_cpu->sg_policy = sg_policy;
+ if (policy_is_shared(policy)) {
+ sg_cpu->util = ULONG_MAX;
+ sg_cpu->max = 0;
+ sg_cpu->last_update = 0;
+ cpufreq_set_update_util_hook(cpu, &sg_cpu->update_hook,
+ sugov_update_shared);
+ } else {
+ cpufreq_set_update_util_hook(cpu, &sg_cpu->update_hook,
+ sugov_update_single);
+ }
+ }
+ return 0;
+}
+
+static int sugov_stop(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+ unsigned int cpu;
+
+ for_each_cpu(cpu, policy->cpus)
+ cpufreq_clear_update_util_hook(cpu);
+
+ synchronize_sched();
+
+ irq_work_sync(&sg_policy->irq_work);
+ cancel_work_sync(&sg_policy->work);
+ return 0;
+}
+
+static int sugov_limits(struct cpufreq_policy *policy)
+{
+ struct sugov_policy *sg_policy = policy->governor_data;
+
+ if (!policy->fast_switch_possible) {
+ mutex_lock(&sg_policy->work_lock);
+
+ if (policy->max < policy->cur)
+ __cpufreq_driver_target(policy, policy->max,
+ CPUFREQ_RELATION_H);
+ else if (policy->min > policy->cur)
+ __cpufreq_driver_target(policy, policy->min,
+ CPUFREQ_RELATION_L);
+
+ mutex_unlock(&sg_policy->work_lock);
+ }
+
+ sg_policy->need_freq_update = true;
+ return 0;
+}
+
+int sugov_governor(struct cpufreq_policy *policy, unsigned int event)
+{
+ if (event == CPUFREQ_GOV_POLICY_INIT) {
+ return sugov_init(policy);
+ } else if (policy->governor_data) {
+ switch (event) {
+ case CPUFREQ_GOV_POLICY_EXIT:
+ return sugov_exit(policy);
+ case CPUFREQ_GOV_START:
+ return sugov_start(policy);
+ case CPUFREQ_GOV_STOP:
+ return sugov_stop(policy);
+ case CPUFREQ_GOV_LIMITS:
+ return sugov_limits(policy);
+ }
+ }
+ return -EINVAL;
+}
+
+static struct cpufreq_governor schedutil_gov = {
+ .name = "schedutil",
+ .governor = sugov_governor,
+ .owner = THIS_MODULE,
+};
+
+static int __init sugov_module_init(void)
+{
+ return cpufreq_register_governor(&schedutil_gov);
+}
+
+static void __exit sugov_module_exit(void)
+{
+ cpufreq_unregister_governor(&schedutil_gov);
+}
+
+MODULE_AUTHOR("Rafael J. Wysocki <rafael.j.wysocki@intel.com>");
+MODULE_DESCRIPTION("Utilization-based CPU frequency selection");
+MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
+struct cpufreq_governor *cpufreq_default_governor(void)
+{
+ return &schedutil_gov;
+}
+
+fs_initcall(sugov_module_init);
+#else
+module_init(sugov_module_init);
+#endif
+module_exit(sugov_module_exit);
===================================================================
@@ -20,3 +20,4 @@ obj-$(CONFIG_SCHEDSTATS) += stats.o
obj-$(CONFIG_SCHED_DEBUG) += debug.o
obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
obj-$(CONFIG_CPU_FREQ) += cpufreq.o
+obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
===================================================================
@@ -34,7 +34,6 @@
* this governor will not work. All times here are in us (micro seconds).
*/
#define MIN_SAMPLING_RATE_RATIO (2)
-#define LATENCY_MULTIPLIER (1000)
#define MIN_LATENCY_MULTIPLIER (20)
#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
===================================================================
@@ -468,6 +468,9 @@ void cpufreq_unregister_governor(struct
struct cpufreq_governor *cpufreq_default_governor(void);
struct cpufreq_governor *cpufreq_fallback_governor(void);
+/* Coefficient for computing default sampling rate/rate limit in governors */
+#define LATENCY_MULTIPLIER (1000)
+
/* Governor attribute set */
struct gov_attr_set {
struct kobject kobj;