2 * drivers/cpufreq/cpufreq_interactive.c
4 * Copyright (C) 2010 Google, Inc.
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * Author: Mike Chan (mike@android.com)
19 #include <linux/cpu.h>
20 #include <linux/cpumask.h>
21 #include <linux/cpufreq.h>
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/rwsem.h>
25 #include <linux/sched.h>
26 #include <linux/sched/rt.h>
27 #include <linux/tick.h>
28 #include <linux/time.h>
29 #include <linux/timer.h>
30 #include <linux/workqueue.h>
31 #include <linux/kthread.h>
32 #include <linux/slab.h>
33 #include <asm/cputime.h>
35 #define CREATE_TRACE_POINTS
36 #include <trace/events/cpufreq_interactive.h>
38 static atomic_t active_count = ATOMIC_INIT(0);
40 struct cpufreq_interactive_cpuinfo {
41 struct timer_list cpu_timer;
42 struct timer_list cpu_slack_timer;
43 spinlock_t load_lock; /* protects the next 4 fields */
45 u64 time_in_idle_timestamp;
47 u64 cputime_speedadj_timestamp;
48 struct cpufreq_policy *policy;
49 struct cpufreq_frequency_table *freq_table;
50 unsigned int target_freq;
51 unsigned int floor_freq;
52 u64 floor_validate_time;
53 u64 hispeed_validate_time;
54 struct rw_semaphore enable_sem;
58 static DEFINE_PER_CPU(struct cpufreq_interactive_cpuinfo, cpuinfo);
60 /* realtime thread handles frequency scaling */
61 static struct task_struct *speedchange_task;
62 static cpumask_t speedchange_cpumask;
63 static spinlock_t speedchange_cpumask_lock;
65 /* Hi speed to bump to from lo speed when load burst (default max) */
66 static unsigned int hispeed_freq;
68 /* Go to hi speed when CPU load at or above this value. */
69 #define DEFAULT_GO_HISPEED_LOAD 99
70 static unsigned long go_hispeed_load = DEFAULT_GO_HISPEED_LOAD;
72 /* Target load. Lower values result in higher CPU speeds. */
73 #define DEFAULT_TARGET_LOAD 90
74 static unsigned int default_target_loads[] = {DEFAULT_TARGET_LOAD};
75 static spinlock_t target_loads_lock;
76 static unsigned int *target_loads = default_target_loads;
77 static int ntarget_loads = ARRAY_SIZE(default_target_loads);
80 * The minimum amount of time to spend at a frequency before we can ramp down.
82 #define DEFAULT_MIN_SAMPLE_TIME (80 * USEC_PER_MSEC)
83 static unsigned long min_sample_time = DEFAULT_MIN_SAMPLE_TIME;
86 * The sample rate of the timer used to increase frequency
88 #define DEFAULT_TIMER_RATE (20 * USEC_PER_MSEC)
89 static unsigned long timer_rate = DEFAULT_TIMER_RATE;
92 * Wait this long before raising speed above hispeed, by default a single
95 #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
96 static unsigned long above_hispeed_delay_val = DEFAULT_ABOVE_HISPEED_DELAY;
98 /* Non-zero means indefinite speed boost active */
100 /* Duration of a boot pulse in usecs */
101 static int boostpulse_duration_val = DEFAULT_MIN_SAMPLE_TIME;
102 /* End time of boost pulse in ktime converted to usecs */
103 static u64 boostpulse_endtime;
106 * Max additional time to wait in idle, beyond timer_rate, at speeds above
107 * minimum before wakeup to reduce speed, or -1 if unnecessary.
109 #define DEFAULT_TIMER_SLACK (4 * DEFAULT_TIMER_RATE)
110 static int timer_slack_val = DEFAULT_TIMER_SLACK;
112 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
115 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
118 struct cpufreq_governor cpufreq_gov_interactive = {
119 .name = "interactive",
120 .governor = cpufreq_governor_interactive,
121 .max_transition_latency = 10000000,
122 .owner = THIS_MODULE,
125 static void cpufreq_interactive_timer_resched(
126 struct cpufreq_interactive_cpuinfo *pcpu)
128 unsigned long expires = jiffies + usecs_to_jiffies(timer_rate);
130 mod_timer_pinned(&pcpu->cpu_timer, expires);
131 if (timer_slack_val >= 0 && pcpu->target_freq > pcpu->policy->min) {
132 expires += usecs_to_jiffies(timer_slack_val);
133 mod_timer_pinned(&pcpu->cpu_slack_timer, expires);
136 spin_lock(&pcpu->load_lock);
138 get_cpu_idle_time_us(smp_processor_id(),
139 &pcpu->time_in_idle_timestamp);
140 pcpu->cputime_speedadj = 0;
141 pcpu->cputime_speedadj_timestamp = pcpu->time_in_idle_timestamp;
142 spin_unlock(&pcpu->load_lock);
145 static unsigned int freq_to_targetload(unsigned int freq)
150 spin_lock(&target_loads_lock);
152 for (i = 0; i < ntarget_loads - 1 && freq >= target_loads[i+1]; i += 2)
155 ret = target_loads[i];
156 spin_unlock(&target_loads_lock);
161 * If increasing frequencies never map to a lower target load then
162 * choose_freq() will find the minimum frequency that does not exceed its
163 * target load given the current load.
166 static unsigned int choose_freq(
167 struct cpufreq_interactive_cpuinfo *pcpu, unsigned int loadadjfreq)
169 unsigned int freq = pcpu->policy->cur;
170 unsigned int prevfreq, freqmin, freqmax;
179 tl = freq_to_targetload(freq);
182 * Find the lowest frequency where the computed load is less
183 * than or equal to the target load.
186 cpufreq_frequency_table_target(
187 pcpu->policy, pcpu->freq_table, loadadjfreq / tl,
188 CPUFREQ_RELATION_L, &index);
189 freq = pcpu->freq_table[index].frequency;
191 if (freq > prevfreq) {
192 /* The previous frequency is too low. */
195 if (freq >= freqmax) {
197 * Find the highest frequency that is less
200 cpufreq_frequency_table_target(
201 pcpu->policy, pcpu->freq_table,
202 freqmax - 1, CPUFREQ_RELATION_H,
204 freq = pcpu->freq_table[index].frequency;
206 if (freq == freqmin) {
208 * The first frequency below freqmax
209 * has already been found to be too
210 * low. freqmax is the lowest speed
211 * we found that is fast enough.
217 } else if (freq < prevfreq) {
218 /* The previous frequency is high enough. */
221 if (freq <= freqmin) {
223 * Find the lowest frequency that is higher
226 cpufreq_frequency_table_target(
227 pcpu->policy, pcpu->freq_table,
228 freqmin + 1, CPUFREQ_RELATION_L,
230 freq = pcpu->freq_table[index].frequency;
233 * If freqmax is the first frequency above
234 * freqmin then we have already found that
235 * this speed is fast enough.
242 /* If same frequency chosen as previous then done. */
243 } while (freq != prevfreq);
248 static u64 update_load(int cpu)
250 struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);
253 unsigned int delta_idle;
254 unsigned int delta_time;
257 now_idle = get_cpu_idle_time_us(cpu, &now);
258 delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
259 delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
260 active_time = delta_time - delta_idle;
261 pcpu->cputime_speedadj += active_time * pcpu->policy->cur;
263 pcpu->time_in_idle = now_idle;
264 pcpu->time_in_idle_timestamp = now;
268 static void cpufreq_interactive_timer(unsigned long data)
271 unsigned int delta_time;
272 u64 cputime_speedadj;
274 struct cpufreq_interactive_cpuinfo *pcpu =
275 &per_cpu(cpuinfo, data);
276 unsigned int new_freq;
277 unsigned int loadadjfreq;
282 if (!down_read_trylock(&pcpu->enable_sem))
284 if (!pcpu->governor_enabled)
287 spin_lock(&pcpu->load_lock);
288 now = update_load(data);
289 delta_time = (unsigned int)(now - pcpu->cputime_speedadj_timestamp);
290 cputime_speedadj = pcpu->cputime_speedadj;
291 spin_unlock(&pcpu->load_lock);
293 if (WARN_ON_ONCE(!delta_time))
296 do_div(cputime_speedadj, delta_time);
297 loadadjfreq = (unsigned int)cputime_speedadj * 100;
298 cpu_load = loadadjfreq / pcpu->target_freq;
299 boosted = boost_val || now < boostpulse_endtime;
301 if (cpu_load >= go_hispeed_load || boosted) {
302 if (pcpu->target_freq < hispeed_freq) {
303 new_freq = hispeed_freq;
305 new_freq = choose_freq(pcpu, loadadjfreq);
307 if (new_freq < hispeed_freq)
308 new_freq = hispeed_freq;
311 new_freq = choose_freq(pcpu, loadadjfreq);
314 if (pcpu->target_freq >= hispeed_freq &&
315 new_freq > pcpu->target_freq &&
316 now - pcpu->hispeed_validate_time < above_hispeed_delay_val) {
317 trace_cpufreq_interactive_notyet(
318 data, cpu_load, pcpu->target_freq,
319 pcpu->policy->cur, new_freq);
323 pcpu->hispeed_validate_time = now;
325 if (cpufreq_frequency_table_target(pcpu->policy, pcpu->freq_table,
326 new_freq, CPUFREQ_RELATION_L,
328 pr_warn_once("timer %d: cpufreq_frequency_table_target error\n",
333 new_freq = pcpu->freq_table[index].frequency;
336 * Do not scale below floor_freq unless we have been at or above the
337 * floor frequency for the minimum sample time since last validated.
339 if (new_freq < pcpu->floor_freq) {
340 if (now - pcpu->floor_validate_time < min_sample_time) {
341 trace_cpufreq_interactive_notyet(
342 data, cpu_load, pcpu->target_freq,
343 pcpu->policy->cur, new_freq);
349 * Update the timestamp for checking whether speed has been held at
350 * or above the selected frequency for a minimum of min_sample_time,
351 * if not boosted to hispeed_freq. If boosted to hispeed_freq then we
352 * allow the speed to drop as soon as the boostpulse duration expires
353 * (or the indefinite boost is turned off).
356 if (!boosted || new_freq > hispeed_freq) {
357 pcpu->floor_freq = new_freq;
358 pcpu->floor_validate_time = now;
361 if (pcpu->target_freq == new_freq) {
362 trace_cpufreq_interactive_already(
363 data, cpu_load, pcpu->target_freq,
364 pcpu->policy->cur, new_freq);
365 goto rearm_if_notmax;
368 trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
369 pcpu->policy->cur, new_freq);
371 pcpu->target_freq = new_freq;
372 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
373 cpumask_set_cpu(data, &speedchange_cpumask);
374 spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
375 wake_up_process(speedchange_task);
379 * Already set max speed and don't see a need to change that,
380 * wait until next idle to re-evaluate, don't need timer.
382 if (pcpu->target_freq == pcpu->policy->max)
386 if (!timer_pending(&pcpu->cpu_timer))
387 cpufreq_interactive_timer_resched(pcpu);
390 up_read(&pcpu->enable_sem);
394 static void cpufreq_interactive_idle_start(void)
396 struct cpufreq_interactive_cpuinfo *pcpu =
397 &per_cpu(cpuinfo, smp_processor_id());
400 if (!down_read_trylock(&pcpu->enable_sem))
402 if (!pcpu->governor_enabled) {
403 up_read(&pcpu->enable_sem);
407 pending = timer_pending(&pcpu->cpu_timer);
409 if (pcpu->target_freq != pcpu->policy->min) {
411 * Entering idle while not at lowest speed. On some
412 * platforms this can hold the other CPU(s) at that speed
413 * even though the CPU is idle. Set a timer to re-evaluate
414 * speed so this idle CPU doesn't hold the other CPUs above
415 * min indefinitely. This should probably be a quirk of
416 * the CPUFreq driver.
419 cpufreq_interactive_timer_resched(pcpu);
422 up_read(&pcpu->enable_sem);
425 static void cpufreq_interactive_idle_end(void)
427 struct cpufreq_interactive_cpuinfo *pcpu =
428 &per_cpu(cpuinfo, smp_processor_id());
430 if (!down_read_trylock(&pcpu->enable_sem))
432 if (!pcpu->governor_enabled) {
433 up_read(&pcpu->enable_sem);
437 /* Arm the timer for 1-2 ticks later if not already. */
438 if (!timer_pending(&pcpu->cpu_timer)) {
439 cpufreq_interactive_timer_resched(pcpu);
440 } else if (time_after_eq(jiffies, pcpu->cpu_timer.expires)) {
441 del_timer(&pcpu->cpu_timer);
442 del_timer(&pcpu->cpu_slack_timer);
443 cpufreq_interactive_timer(smp_processor_id());
446 up_read(&pcpu->enable_sem);
449 static int cpufreq_interactive_speedchange_task(void *data)
454 struct cpufreq_interactive_cpuinfo *pcpu;
457 set_current_state(TASK_INTERRUPTIBLE);
458 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
460 if (cpumask_empty(&speedchange_cpumask)) {
461 spin_unlock_irqrestore(&speedchange_cpumask_lock,
465 if (kthread_should_stop())
468 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
471 set_current_state(TASK_RUNNING);
472 tmp_mask = speedchange_cpumask;
473 cpumask_clear(&speedchange_cpumask);
474 spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
476 for_each_cpu(cpu, &tmp_mask) {
478 unsigned int max_freq = 0;
480 pcpu = &per_cpu(cpuinfo, cpu);
481 if (!down_read_trylock(&pcpu->enable_sem))
483 if (!pcpu->governor_enabled) {
484 up_read(&pcpu->enable_sem);
488 for_each_cpu(j, pcpu->policy->cpus) {
489 struct cpufreq_interactive_cpuinfo *pjcpu =
490 &per_cpu(cpuinfo, j);
492 if (pjcpu->target_freq > max_freq)
493 max_freq = pjcpu->target_freq;
496 if (max_freq != pcpu->policy->cur)
497 __cpufreq_driver_target(pcpu->policy,
500 trace_cpufreq_interactive_setspeed(cpu,
504 up_read(&pcpu->enable_sem);
511 static void cpufreq_interactive_boost(void)
516 struct cpufreq_interactive_cpuinfo *pcpu;
518 spin_lock_irqsave(&speedchange_cpumask_lock, flags);
520 for_each_online_cpu(i) {
521 pcpu = &per_cpu(cpuinfo, i);
523 if (pcpu->target_freq < hispeed_freq) {
524 pcpu->target_freq = hispeed_freq;
525 cpumask_set_cpu(i, &speedchange_cpumask);
526 pcpu->hispeed_validate_time =
527 ktime_to_us(ktime_get());
532 * Set floor freq and (re)start timer for when last
536 pcpu->floor_freq = hispeed_freq;
537 pcpu->floor_validate_time = ktime_to_us(ktime_get());
540 spin_unlock_irqrestore(&speedchange_cpumask_lock, flags);
543 wake_up_process(speedchange_task);
546 static int cpufreq_interactive_notifier(
547 struct notifier_block *nb, unsigned long val, void *data)
549 struct cpufreq_freqs *freq = data;
550 struct cpufreq_interactive_cpuinfo *pcpu;
553 if (val == CPUFREQ_POSTCHANGE) {
554 pcpu = &per_cpu(cpuinfo, freq->cpu);
556 for_each_cpu(cpu, pcpu->policy->cpus) {
557 struct cpufreq_interactive_cpuinfo *pjcpu =
558 &per_cpu(cpuinfo, cpu);
559 spin_lock(&pjcpu->load_lock);
561 spin_unlock(&pjcpu->load_lock);
568 static struct notifier_block cpufreq_notifier_block = {
569 .notifier_call = cpufreq_interactive_notifier,
572 static ssize_t show_target_loads(
573 struct kobject *kobj, struct attribute *attr, char *buf)
578 spin_lock(&target_loads_lock);
580 for (i = 0; i < ntarget_loads; i++)
581 ret += sprintf(buf + ret, "%u%s", target_loads[i],
582 i & 0x1 ? ":" : " ");
584 ret += sprintf(buf + ret, "\n");
585 spin_unlock(&target_loads_lock);
589 static ssize_t store_target_loads(
590 struct kobject *kobj, struct attribute *attr, const char *buf,
595 unsigned int *new_target_loads = NULL;
600 while ((cp = strpbrk(cp + 1, " :")))
603 if (!(ntokens & 0x1))
606 new_target_loads = kmalloc(ntokens * sizeof(unsigned int), GFP_KERNEL);
607 if (!new_target_loads) {
614 while (i < ntokens) {
615 if (sscanf(cp, "%u", &new_target_loads[i++]) != 1)
618 cp = strpbrk(cp, " :");
627 spin_lock(&target_loads_lock);
628 if (target_loads != default_target_loads)
630 target_loads = new_target_loads;
631 ntarget_loads = ntokens;
632 spin_unlock(&target_loads_lock);
638 kfree(new_target_loads);
642 static struct global_attr target_loads_attr =
643 __ATTR(target_loads, S_IRUGO | S_IWUSR,
644 show_target_loads, store_target_loads);
646 static ssize_t show_hispeed_freq(struct kobject *kobj,
647 struct attribute *attr, char *buf)
649 return sprintf(buf, "%u\n", hispeed_freq);
652 static ssize_t store_hispeed_freq(struct kobject *kobj,
653 struct attribute *attr, const char *buf,
657 long unsigned int val;
659 ret = strict_strtoul(buf, 0, &val);
666 static struct global_attr hispeed_freq_attr = __ATTR(hispeed_freq, 0644,
667 show_hispeed_freq, store_hispeed_freq);
670 static ssize_t show_go_hispeed_load(struct kobject *kobj,
671 struct attribute *attr, char *buf)
673 return sprintf(buf, "%lu\n", go_hispeed_load);
676 static ssize_t store_go_hispeed_load(struct kobject *kobj,
677 struct attribute *attr, const char *buf, size_t count)
682 ret = strict_strtoul(buf, 0, &val);
685 go_hispeed_load = val;
689 static struct global_attr go_hispeed_load_attr = __ATTR(go_hispeed_load, 0644,
690 show_go_hispeed_load, store_go_hispeed_load);
692 static ssize_t show_min_sample_time(struct kobject *kobj,
693 struct attribute *attr, char *buf)
695 return sprintf(buf, "%lu\n", min_sample_time);
698 static ssize_t store_min_sample_time(struct kobject *kobj,
699 struct attribute *attr, const char *buf, size_t count)
704 ret = strict_strtoul(buf, 0, &val);
707 min_sample_time = val;
711 static struct global_attr min_sample_time_attr = __ATTR(min_sample_time, 0644,
712 show_min_sample_time, store_min_sample_time);
714 static ssize_t show_above_hispeed_delay(struct kobject *kobj,
715 struct attribute *attr, char *buf)
717 return sprintf(buf, "%lu\n", above_hispeed_delay_val);
720 static ssize_t store_above_hispeed_delay(struct kobject *kobj,
721 struct attribute *attr,
722 const char *buf, size_t count)
727 ret = strict_strtoul(buf, 0, &val);
730 above_hispeed_delay_val = val;
734 define_one_global_rw(above_hispeed_delay);
736 static ssize_t show_timer_rate(struct kobject *kobj,
737 struct attribute *attr, char *buf)
739 return sprintf(buf, "%lu\n", timer_rate);
742 static ssize_t store_timer_rate(struct kobject *kobj,
743 struct attribute *attr, const char *buf, size_t count)
748 ret = strict_strtoul(buf, 0, &val);
755 static struct global_attr timer_rate_attr = __ATTR(timer_rate, 0644,
756 show_timer_rate, store_timer_rate);
758 static ssize_t show_timer_slack(
759 struct kobject *kobj, struct attribute *attr, char *buf)
761 return sprintf(buf, "%d\n", timer_slack_val);
764 static ssize_t store_timer_slack(
765 struct kobject *kobj, struct attribute *attr, const char *buf,
771 ret = kstrtol(buf, 10, &val);
775 timer_slack_val = val;
779 define_one_global_rw(timer_slack);
781 static ssize_t show_boost(struct kobject *kobj, struct attribute *attr,
784 return sprintf(buf, "%d\n", boost_val);
787 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
788 const char *buf, size_t count)
793 ret = kstrtoul(buf, 0, &val);
800 trace_cpufreq_interactive_boost("on");
801 cpufreq_interactive_boost();
803 trace_cpufreq_interactive_unboost("off");
809 define_one_global_rw(boost);
811 static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
812 const char *buf, size_t count)
817 ret = kstrtoul(buf, 0, &val);
821 boostpulse_endtime = ktime_to_us(ktime_get()) + boostpulse_duration_val;
822 trace_cpufreq_interactive_boost("pulse");
823 cpufreq_interactive_boost();
827 static struct global_attr boostpulse =
828 __ATTR(boostpulse, 0200, NULL, store_boostpulse);
830 static ssize_t show_boostpulse_duration(
831 struct kobject *kobj, struct attribute *attr, char *buf)
833 return sprintf(buf, "%d\n", boostpulse_duration_val);
836 static ssize_t store_boostpulse_duration(
837 struct kobject *kobj, struct attribute *attr, const char *buf,
843 ret = kstrtoul(buf, 0, &val);
847 boostpulse_duration_val = val;
851 define_one_global_rw(boostpulse_duration);
853 static struct attribute *interactive_attributes[] = {
854 &target_loads_attr.attr,
855 &hispeed_freq_attr.attr,
856 &go_hispeed_load_attr.attr,
857 &above_hispeed_delay.attr,
858 &min_sample_time_attr.attr,
859 &timer_rate_attr.attr,
863 &boostpulse_duration.attr,
867 static struct attribute_group interactive_attr_group = {
868 .attrs = interactive_attributes,
869 .name = "interactive",
872 static int cpufreq_interactive_idle_notifier(struct notifier_block *nb,
878 cpufreq_interactive_idle_start();
881 cpufreq_interactive_idle_end();
888 static struct notifier_block cpufreq_interactive_idle_nb = {
889 .notifier_call = cpufreq_interactive_idle_notifier,
892 static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
897 struct cpufreq_interactive_cpuinfo *pcpu;
898 struct cpufreq_frequency_table *freq_table;
901 case CPUFREQ_GOV_START:
902 if (!cpu_online(policy->cpu))
906 cpufreq_frequency_get_table(policy->cpu);
908 hispeed_freq = policy->max;
910 for_each_cpu(j, policy->cpus) {
911 unsigned long expires;
913 pcpu = &per_cpu(cpuinfo, j);
914 pcpu->policy = policy;
915 pcpu->target_freq = policy->cur;
916 pcpu->freq_table = freq_table;
917 pcpu->floor_freq = pcpu->target_freq;
918 pcpu->floor_validate_time =
919 ktime_to_us(ktime_get());
920 pcpu->hispeed_validate_time =
921 pcpu->floor_validate_time;
922 down_write(&pcpu->enable_sem);
923 expires = jiffies + usecs_to_jiffies(timer_rate);
924 pcpu->cpu_timer.expires = expires;
925 add_timer_on(&pcpu->cpu_timer, j);
926 if (timer_slack_val >= 0) {
927 expires += usecs_to_jiffies(timer_slack_val);
928 pcpu->cpu_slack_timer.expires = expires;
929 add_timer_on(&pcpu->cpu_slack_timer, j);
931 pcpu->governor_enabled = 1;
932 up_write(&pcpu->enable_sem);
936 * Do not register the idle hook and create sysfs
937 * entries if we have already done so.
939 if (atomic_inc_return(&active_count) > 1)
942 rc = sysfs_create_group(cpufreq_global_kobject,
943 &interactive_attr_group);
947 idle_notifier_register(&cpufreq_interactive_idle_nb);
948 cpufreq_register_notifier(
949 &cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
952 case CPUFREQ_GOV_STOP:
953 for_each_cpu(j, policy->cpus) {
954 pcpu = &per_cpu(cpuinfo, j);
955 down_write(&pcpu->enable_sem);
956 pcpu->governor_enabled = 0;
957 del_timer_sync(&pcpu->cpu_timer);
958 del_timer_sync(&pcpu->cpu_slack_timer);
959 up_write(&pcpu->enable_sem);
962 if (atomic_dec_return(&active_count) > 0)
965 cpufreq_unregister_notifier(
966 &cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
967 idle_notifier_unregister(&cpufreq_interactive_idle_nb);
968 sysfs_remove_group(cpufreq_global_kobject,
969 &interactive_attr_group);
973 case CPUFREQ_GOV_LIMITS:
974 if (policy->max < policy->cur)
975 __cpufreq_driver_target(policy,
976 policy->max, CPUFREQ_RELATION_H);
977 else if (policy->min > policy->cur)
978 __cpufreq_driver_target(policy,
979 policy->min, CPUFREQ_RELATION_L);
985 static void cpufreq_interactive_nop_timer(unsigned long data)
989 static int __init cpufreq_interactive_init(void)
992 struct cpufreq_interactive_cpuinfo *pcpu;
993 struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
995 /* Initalize per-cpu timers */
996 for_each_possible_cpu(i) {
997 pcpu = &per_cpu(cpuinfo, i);
998 init_timer_deferrable(&pcpu->cpu_timer);
999 pcpu->cpu_timer.function = cpufreq_interactive_timer;
1000 pcpu->cpu_timer.data = i;
1001 init_timer(&pcpu->cpu_slack_timer);
1002 pcpu->cpu_slack_timer.function = cpufreq_interactive_nop_timer;
1003 spin_lock_init(&pcpu->load_lock);
1004 init_rwsem(&pcpu->enable_sem);
1007 spin_lock_init(&target_loads_lock);
1008 spin_lock_init(&speedchange_cpumask_lock);
1010 kthread_create(cpufreq_interactive_speedchange_task, NULL,
1012 if (IS_ERR(speedchange_task))
1013 return PTR_ERR(speedchange_task);
1015 sched_setscheduler_nocheck(speedchange_task, SCHED_FIFO, ¶m);
1016 get_task_struct(speedchange_task);
1018 /* NB: wake up so the thread does not look hung to the freezer */
1019 wake_up_process(speedchange_task);
1021 return cpufreq_register_governor(&cpufreq_gov_interactive);
1024 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_INTERACTIVE
1025 fs_initcall(cpufreq_interactive_init);
1027 module_init(cpufreq_interactive_init);
1030 static void __exit cpufreq_interactive_exit(void)
1032 cpufreq_unregister_governor(&cpufreq_gov_interactive);
1033 kthread_stop(speedchange_task);
1034 put_task_struct(speedchange_task);
1037 module_exit(cpufreq_interactive_exit);
1039 MODULE_AUTHOR("Mike Chan <mike@android.com>");
1040 MODULE_DESCRIPTION("'cpufreq_interactive' - A cpufreq governor for "
1041 "Latency sensitive workloads");
1042 MODULE_LICENSE("GPL");