/* * drivers/cpufreq/cpufreq_interactive.c * * Copyright (C) 2010 Google, Inc. * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * 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. * * Author: Mike Chan (mike@android.com) * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include static atomic_t active_count = ATOMIC_INIT(0); struct cpufreq_interactive_cpuinfo { struct timer_list cpu_timer; int timer_idlecancel; u64 time_in_idle; u64 time_in_idle_timestamp; u64 target_set_time; u64 target_set_time_in_idle; struct cpufreq_policy *policy; struct cpufreq_frequency_table *freq_table; unsigned int target_freq; unsigned int floor_freq; u64 floor_validate_time; u64 hispeed_validate_time; int governor_enabled; }; static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo); /* realtime thread handles frequency scaling */ static struct task_struct *speedchange_task; static cpumask_t speedchange_cpumask; static spinlock_t speedchange_cpumask_lock; /* Hi speed to bump to from lo speed when load burst (default max) */ static unsigned int hispeed_freq; /* Go to hi speed when CPU load at or above this value. */ #define DEFAULT_GO_HISPEED_LOAD 85 static unsigned long go_hispeed_load; /* Target load. Lower values result in higher CPU speeds. */ #define DEFAULT_TARGET_LOAD 90 static unsigned long target_load = DEFAULT_TARGET_LOAD; /* * The minimum amount of time to spend at a frequency before we can ramp down. */ #define DEFAULT_MIN_SAMPLE_TIME (80 * USEC_PER_MSEC) static unsigned long min_sample_time; /* * The sample rate of the timer used to increase frequency */ #define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC) static unsigned long timer_rate; /* * Wait this long before raising speed above hispeed, by default a single * timer interval. */ #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE static unsigned long above_hispeed_delay_val; /* * Non-zero means longer-term speed boost active. */ static int boost_val; static bool governidle; module_param(governidle, bool, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(governidle, "Set to 1 to wake up CPUs from idle to reduce speed (default 0)"); static int cpufreq_governor_interactive(struct cpufreq_policy *policy, unsigned int event); #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE static #endif struct cpufreq_governor cpufreq_gov_interactive = { .name = "interactive", .governor = cpufreq_governor_interactive, .max_transition_latency = 10000000, .owner = THIS_MODULE, }; static void cpufreq_interactive_timer_resched( struct cpufreq_interactive_cpuinfo *pcpu) { mod_timer_pinned(&pcpu->cpu_timer, jiffies + usecs_to_jiffies(timer_rate)); pcpu->time_in_idle = get_cpu_idle_time_us(smp_processor_id(), &pcpu->time_in_idle_timestamp); } static void cpufreq_interactive_timer(unsigned long data) { u64 now; unsigned int delta_idle; unsigned int delta_time; int cpu_load; int load_since_change; struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, data); u64 now_idle; unsigned int new_freq; unsigned int index; unsigned long flags; smp_rmb(); if (!pcpu->governor_enabled) goto exit; now_idle = get_cpu_idle_time_us(data, &now); delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle); delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp); /* * If timer ran less than 1ms after short-term sample started, retry. */ if (delta_time < 1000) goto rearm; if (delta_idle > delta_time) cpu_load = 0; else cpu_load = 100 * (delta_time - delta_idle) / delta_time; delta_idle = (unsigned int)(now_idle - pcpu->target_set_time_in_idle); delta_time = (unsigned int)(now - pcpu->target_set_time); if ((delta_time == 0) || (delta_idle > delta_time)) load_since_change = 0; else load_since_change = 100 * (delta_time - delta_idle) / delta_time; /* * Choose greater of short-term load (since last idle timer * started or timer function re-armed itself) or long-term load * (since last frequency change). */ if (load_since_change > cpu_load) cpu_load = load_since_change; if ((cpu_load >= go_hispeed_load || boost_val) && pcpu->target_freq < hispeed_freq) new_freq = hispeed_freq; else new_freq = pcpu->policy->cur * cpu_load / target_load; if (pcpu->target_freq >= hispeed_freq && new_freq > pcpu->target_freq && now - pcpu->hispeed_validate_time < above_hispeed_delay_val) { trace_cpufreq_interactive_notyet( data, cpu_load, pcpu->target_freq, pcpu->policy->cur, new_freq); goto rearm; } pcpu->hispeed_validate_time = now; if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table, new_freq, CPUFREQ_RELATION_L, &index)) { pr_warn_once("timer %d: cpufreq_frequency_table_target error\n", (int) data); goto rearm; } new_freq = pcpu->freq_table[index].frequency; /* * Do not scale below floor_freq unless we have been at or above the * floor frequency for the minimum sample time since last validated. */ if (new_freq < pcpu->floor_freq) { if (now - pcpu->floor_validate_time < min_sample_time) { trace_cpufreq_interactive_notyet( data, cpu_load, pcpu->target_freq, pcpu->policy->cur, new_freq); goto rearm; } } pcpu->floor_freq = new_freq; pcpu->floor_validate_time = now; if (pcpu->target_freq == new_freq) { trace_cpufreq_interactive_already( data, cpu_load, pcpu->target_freq, pcpu->policy->cur, new_freq); goto rearm_if_notmax; } trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq, pcpu->policy->cur, new_freq); pcpu->target_set_time_in_idle = now_idle; pcpu->target_set_time = now; pcpu->target_freq = new_freq; spin_lock_irqsave(&speedchange_cpumask_lock, flags); cpumask_set_cpu(data, &speedchange_cpumask); spin_unlock_irqrestore(&speedchange_cpumask_lock, flags); wake_up_process(speedchange_task); rearm_if_notmax: /* * Already set max speed and don't see a need to change that, * wait until next idle to re-evaluate, don't need timer. */ if (pcpu->target_freq == pcpu->policy->max) goto exit; rearm: if (!timer_pending(&pcpu->cpu_timer)) { /* * If governing speed in idle and already at min, cancel the * timer if that CPU goes idle. We don't need to re-evaluate * speed until the next idle exit. */ if (governidle && pcpu->target_freq == pcpu->policy->min) pcpu->timer_idlecancel = 1; cpufreq_interactive_timer_resched(pcpu); } exit: return; } static void cpufreq_interactive_idle_start(void) { struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, smp_processor_id()); int pending; if (!pcpu->governor_enabled) return; pending = timer_pending(&pcpu->cpu_timer); if (pcpu->target_freq != pcpu->policy->min) { /* * Entering idle while not at lowest speed. On some * platforms this can hold the other CPU(s) at that speed * even though the CPU is idle. Set a timer to re-evaluate * speed so this idle CPU doesn't hold the other CPUs above * min indefinitely. This should probably be a quirk of * the CPUFreq driver. */ if (!pending) { pcpu->timer_idlecancel = 0; cpufreq_interactive_timer_resched(pcpu); } } else if (governidle) { /* * If at min speed and entering idle after load has * already been evaluated, and a timer has been set just in * case the CPU suddenly goes busy, cancel that timer. The * CPU didn't go busy; we'll recheck things upon idle exit. */ if (pending && pcpu->timer_idlecancel) { del_timer(&pcpu->cpu_timer); pcpu->timer_idlecancel = 0; } } } static void cpufreq_interactive_idle_end(void) { struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, smp_processor_id()); if (!pcpu->governor_enabled) return; /* Arm the timer for 1-2 ticks later if not already. */ if (!timer_pending(&pcpu->cpu_timer)) { pcpu->timer_idlecancel = 0; cpufreq_interactive_timer_resched(pcpu); } else if (!governidle && time_after_eq(jiffies, pcpu->cpu_timer.expires)) { del_timer(&pcpu->cpu_timer); cpufreq_interactive_timer(smp_processor_id()); } } static int cpufreq_interactive_speedchange_task(void *data) { unsigned int cpu; cpumask_t tmp_mask; unsigned long flags; struct cpufreq_interactive_cpuinfo *pcpu; while (1) { set_current_state(TASK_INTERRUPTIBLE); spin_lock_irqsave(&speedchange_cpumask_lock, flags); if (cpumask_empty(&speedchange_cpumask)) { spin_unlock_irqrestore(&speedchange_cpumask_lock, flags); schedule(); if (kthread_should_stop()) break; spin_lock_irqsave(&speedchange_cpumask_lock, flags); } set_current_state(TASK_RUNNING); tmp_mask = speedchange_cpumask; cpumask_clear(&speedchange_cpumask); spin_unlock_irqrestore(&speedchange_cpumask_lock, flags); for_each_cpu(cpu, &tmp_mask) { unsigned int j; unsigned int max_freq = 0; pcpu = &per_cpu(cpuinfo, cpu); smp_rmb(); if (!pcpu->governor_enabled) continue; for_each_cpu(j, pcpu->policy->cpus) { struct cpufreq_interactive_cpuinfo *pjcpu = &per_cpu(cpuinfo, j); if (pjcpu->target_freq > max_freq) max_freq = pjcpu->target_freq; } if (max_freq != pcpu->policy->cur) __cpufreq_driver_target(pcpu->policy, max_freq, CPUFREQ_RELATION_H); trace_cpufreq_interactive_setspeed(cpu, pcpu->target_freq, pcpu->policy->cur); } } return 0; } static void cpufreq_interactive_boost(void) { int i; int anyboost = 0; unsigned long flags; struct cpufreq_interactive_cpuinfo *pcpu; spin_lock_irqsave(&speedchange_cpumask_lock, flags); for_each_online_cpu(i) { pcpu = &per_cpu(cpuinfo, i); if (pcpu->target_freq < hispeed_freq) { pcpu->target_freq = hispeed_freq; cpumask_set_cpu(i, &speedchange_cpumask); pcpu->target_set_time_in_idle = get_cpu_idle_time_us(i, &pcpu->target_set_time); pcpu->hispeed_validate_time = pcpu->target_set_time; anyboost = 1; } /* * Set floor freq and (re)start timer for when last * validated. */ pcpu->floor_freq = hispeed_freq; pcpu->floor_validate_time = ktime_to_us(ktime_get()); } spin_unlock_irqrestore(&speedchange_cpumask_lock, flags); if (anyboost) wake_up_process(speedchange_task); } static ssize_t show_target_load( struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%lu\n", target_load); } static ssize_t store_target_load( struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; target_load = val; return count; } static struct global_attr target_load_attr = __ATTR(target_load, S_IRUGO | S_IWUSR, show_target_load, store_target_load); static ssize_t show_hispeed_freq(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%u\n", hispeed_freq); } static ssize_t store_hispeed_freq(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; long unsigned int val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; hispeed_freq = val; return count; } static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644, show_hispeed_freq, store_hispeed_freq); static ssize_t show_go_hispeed_load(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%lu\n", go_hispeed_load); } static ssize_t store_go_hispeed_load(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; go_hispeed_load = val; return count; } static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644, show_go_hispeed_load, store_go_hispeed_load); static ssize_t show_min_sample_time(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%lu\n", min_sample_time); } static ssize_t store_min_sample_time(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; min_sample_time = val; return count; } static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644, show_min_sample_time, store_min_sample_time); static ssize_t show_above_hispeed_delay(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%lu\n", above_hispeed_delay_val); } static ssize_t store_above_hispeed_delay(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; above_hispeed_delay_val = val; return count; } define_one_global_rw(above_hispeed_delay); static ssize_t show_timer_rate(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%lu\n", timer_rate); } static ssize_t store_timer_rate(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = strict_strtoul(buf, 0, &val); if (ret < 0) return ret; timer_rate = val; return count; } static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644, show_timer_rate, store_timer_rate); static ssize_t show_boost(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%d\n", boost_val); } static ssize_t store_boost(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = kstrtoul(buf, 0, &val); if (ret < 0) return ret; boost_val = val; if (boost_val) { trace_cpufreq_interactive_boost("on"); cpufreq_interactive_boost(); } else { trace_cpufreq_interactive_unboost("off"); } return count; } define_one_global_rw(boost); static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { int ret; unsigned long val; ret = kstrtoul(buf, 0, &val); if (ret < 0) return ret; trace_cpufreq_interactive_boost("pulse"); cpufreq_interactive_boost(); return count; } static struct global_attr boostpulse = __ATTR(boostpulse, 0200, NULL, store_boostpulse); static struct attribute *interactive_attributes[] = { &target_load_attr.attr, &hispeed_freq_attr.attr, &go_hispeed_load_attr.attr, &above_hispeed_delay.attr, &min_sample_time_attr.attr, &timer_rate_attr.attr, &boost.attr, &boostpulse.attr, NULL, }; static struct attribute_group interactive_attr_group = { .attrs = interactive_attributes, .name = "interactive", }; static int cpufreq_interactive_idle_notifier(struct notifier_block *nb, unsigned long val, void *data) { switch (val) { case IDLE_START: cpufreq_interactive_idle_start(); break; case IDLE_END: cpufreq_interactive_idle_end(); break; } return 0; } static struct notifier_block cpufreq_interactive_idle_nb = { .notifier_call = cpufreq_interactive_idle_notifier, }; static int cpufreq_governor_interactive(struct cpufreq_policy *policy, unsigned int event) { int rc; unsigned int j; struct cpufreq_interactive_cpuinfo *pcpu; struct cpufreq_frequency_table *freq_table; switch (event) { case CPUFREQ_GOV_START: if (!cpu_online(policy->cpu)) return -EINVAL; freq_table = cpufreq_frequency_get_table(policy->cpu); if (!hispeed_freq) hispeed_freq = policy->max; for_each_cpu(j, policy->cpus) { pcpu = &per_cpu(cpuinfo, j); pcpu->policy = policy; pcpu->target_freq = policy->cur; pcpu->freq_table = freq_table; pcpu->target_set_time_in_idle = get_cpu_idle_time_us(j, &pcpu->target_set_time); pcpu->floor_freq = pcpu->target_freq; pcpu->floor_validate_time = pcpu->target_set_time; pcpu->hispeed_validate_time = pcpu->target_set_time; pcpu->governor_enabled = 1; smp_wmb(); pcpu->cpu_timer.expires = jiffies + usecs_to_jiffies(timer_rate); add_timer_on(&pcpu->cpu_timer, j); } /* * Do not register the idle hook and create sysfs * entries if we have already done so. */ if (atomic_inc_return(&active_count) > 1) return 0; rc = sysfs_create_group(cpufreq_global_kobject, &interactive_attr_group); if (rc) return rc; idle_notifier_register(&cpufreq_interactive_idle_nb); break; case CPUFREQ_GOV_STOP: for_each_cpu(j, policy->cpus) { pcpu = &per_cpu(cpuinfo, j); pcpu->governor_enabled = 0; smp_wmb(); del_timer_sync(&pcpu->cpu_timer); } if (atomic_dec_return(&active_count) > 0) return 0; idle_notifier_unregister(&cpufreq_interactive_idle_nb); sysfs_remove_group(cpufreq_global_kobject, &interactive_attr_group); break; case CPUFREQ_GOV_LIMITS: 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); break; } return 0; } static int __init cpufreq_interactive_init(void) { unsigned int i; struct cpufreq_interactive_cpuinfo *pcpu; struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; go_hispeed_load = DEFAULT_GO_HISPEED_LOAD; min_sample_time = DEFAULT_MIN_SAMPLE_TIME; above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY; timer_rate = DEFAULT_TIMER_RATE; /* Initalize per-cpu timers */ for_each_possible_cpu(i) { pcpu = &per_cpu(cpuinfo, i); if (governidle) init_timer(&pcpu->cpu_timer); else init_timer_deferrable(&pcpu->cpu_timer); pcpu->cpu_timer.function = cpufreq_interactive_timer; pcpu->cpu_timer.data = i; } spin_lock_init(&speedchange_cpumask_lock); speedchange_task = kthread_create(cpufreq_interactive_speedchange_task, NULL, "cfinteractive"); if (IS_ERR(speedchange_task)) return PTR_ERR(speedchange_task); sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, ¶m); get_task_struct(speedchange_task); /* NB: wake up so the thread does not look hung to the freezer */ wake_up_process(speedchange_task); return cpufreq_register_governor(&cpufreq_gov_interactive); } #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE fs_initcall(cpufreq_interactive_init); #else module_init(cpufreq_interactive_init); #endif static void __exit cpufreq_interactive_exit(void) { cpufreq_unregister_governor(&cpufreq_gov_interactive); kthread_stop(speedchange_task); put_task_struct(speedchange_task); } module_exit(cpufreq_interactive_exit); MODULE_AUTHOR("Mike Chan "); MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for " "Latency sensitive workloads"); MODULE_LICENSE("GPL");