GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / cpufreq_ondemand.c
1 /*
2  *  drivers/cpufreq/cpufreq_ondemand.c
3  *
4  *  Copyright (C)  2001 Russell King
5  *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6  *                      Jun Nakajima <jun.nakajima@intel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/cpu.h>
16 #include <linux/percpu-defs.h>
17 #include <linux/slab.h>
18 #include <linux/tick.h>
19 #include "cpufreq_governor.h"
20
21 /* On-demand governor macros */
22 #define DEF_FREQUENCY_UP_THRESHOLD              (80)
23 #define DEF_SAMPLING_DOWN_FACTOR                (1)
24 #define MAX_SAMPLING_DOWN_FACTOR                (100000)
25 #define MICRO_FREQUENCY_UP_THRESHOLD            (95)
26 #define MICRO_FREQUENCY_MIN_SAMPLE_RATE         (10000)
27 #define MIN_FREQUENCY_UP_THRESHOLD              (11)
28 #define MAX_FREQUENCY_UP_THRESHOLD              (100)
29
30 static DEFINE_PER_CPU(struct od_cpu_dbs_info_s, od_cpu_dbs_info);
31
32 static struct od_ops od_ops;
33
34 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
35 static struct cpufreq_governor cpufreq_gov_ondemand;
36 #endif
37
38 static unsigned int default_powersave_bias;
39
40 static void ondemand_powersave_bias_init_cpu(int cpu)
41 {
42         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
43
44         dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
45         dbs_info->freq_lo = 0;
46 }
47
48 /*
49  * Not all CPUs want IO time to be accounted as busy; this depends on how
50  * efficient idling at a higher frequency/voltage is.
51  * Pavel Machek says this is not so for various generations of AMD and old
52  * Intel systems.
53  * Mike Chan (android.com) claims this is also not true for ARM.
54  * Because of this, whitelist specific known (series) of CPUs by default, and
55  * leave all others up to the user.
56  */
57 static int should_io_be_busy(void)
58 {
59 #if defined(CONFIG_X86)
60         /*
61          * For Intel, Core 2 (model 15) and later have an efficient idle.
62          */
63         if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
64                         boot_cpu_data.x86 == 6 &&
65                         boot_cpu_data.x86_model >= 15)
66                 return 1;
67 #endif
68         return 0;
69 }
70
71 /*
72  * Find right freq to be set now with powersave_bias on.
73  * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
74  * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
75  */
76 static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy,
77                 unsigned int freq_next, unsigned int relation)
78 {
79         unsigned int freq_req, freq_reduc, freq_avg;
80         unsigned int freq_hi, freq_lo;
81         unsigned int index = 0;
82         unsigned int jiffies_total, jiffies_hi, jiffies_lo;
83         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
84                                                    policy->cpu);
85         struct dbs_data *dbs_data = policy->governor_data;
86         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
87
88         if (!dbs_info->freq_table) {
89                 dbs_info->freq_lo = 0;
90                 dbs_info->freq_lo_jiffies = 0;
91                 return freq_next;
92         }
93
94         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
95                         relation, &index);
96         freq_req = dbs_info->freq_table[index].frequency;
97         freq_reduc = freq_req * od_tuners->powersave_bias / 1000;
98         freq_avg = freq_req - freq_reduc;
99
100         /* Find freq bounds for freq_avg in freq_table */
101         index = 0;
102         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
103                         CPUFREQ_RELATION_H, &index);
104         freq_lo = dbs_info->freq_table[index].frequency;
105         index = 0;
106         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
107                         CPUFREQ_RELATION_L, &index);
108         freq_hi = dbs_info->freq_table[index].frequency;
109
110         /* Find out how long we have to be in hi and lo freqs */
111         if (freq_hi == freq_lo) {
112                 dbs_info->freq_lo = 0;
113                 dbs_info->freq_lo_jiffies = 0;
114                 return freq_lo;
115         }
116         jiffies_total = usecs_to_jiffies(od_tuners->sampling_rate);
117         jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
118         jiffies_hi += ((freq_hi - freq_lo) / 2);
119         jiffies_hi /= (freq_hi - freq_lo);
120         jiffies_lo = jiffies_total - jiffies_hi;
121         dbs_info->freq_lo = freq_lo;
122         dbs_info->freq_lo_jiffies = jiffies_lo;
123         dbs_info->freq_hi_jiffies = jiffies_hi;
124         return freq_hi;
125 }
126
127 static void ondemand_powersave_bias_init(void)
128 {
129         int i;
130         for_each_online_cpu(i) {
131                 ondemand_powersave_bias_init_cpu(i);
132         }
133 }
134
135 static void dbs_freq_increase(struct cpufreq_policy *policy, unsigned int freq)
136 {
137         struct dbs_data *dbs_data = policy->governor_data;
138         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
139
140         if (od_tuners->powersave_bias)
141                 freq = od_ops.powersave_bias_target(policy, freq,
142                                 CPUFREQ_RELATION_H);
143         else if (policy->cur == policy->max)
144                 return;
145
146         __cpufreq_driver_target(policy, freq, od_tuners->powersave_bias ?
147                         CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
148 }
149
150 /*
151  * Every sampling_rate, we check, if current idle time is less than 20%
152  * (default), then we try to increase frequency. Else, we adjust the frequency
153  * proportional to load.
154  */
155 static void od_check_cpu(int cpu, unsigned int load)
156 {
157         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
158         struct cpufreq_policy *policy = dbs_info->cdbs.shared->policy;
159         struct dbs_data *dbs_data = policy->governor_data;
160         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
161
162         dbs_info->freq_lo = 0;
163
164         /* Check for frequency increase */
165         if (load > od_tuners->up_threshold) {
166                 /* If switching to max speed, apply sampling_down_factor */
167                 if (policy->cur < policy->max)
168                         dbs_info->rate_mult =
169                                 od_tuners->sampling_down_factor;
170                 dbs_freq_increase(policy, policy->max);
171         } else {
172                 /* Calculate the next frequency proportional to load */
173                 unsigned int freq_next, min_f, max_f;
174
175                 min_f = policy->cpuinfo.min_freq;
176                 max_f = policy->cpuinfo.max_freq;
177                 freq_next = min_f + load * (max_f - min_f) / 100;
178
179                 /* No longer fully busy, reset rate_mult */
180                 dbs_info->rate_mult = 1;
181
182                 if (!od_tuners->powersave_bias) {
183                         __cpufreq_driver_target(policy, freq_next,
184                                         CPUFREQ_RELATION_C);
185                         return;
186                 }
187
188                 freq_next = od_ops.powersave_bias_target(policy, freq_next,
189                                         CPUFREQ_RELATION_L);
190                 __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_C);
191         }
192 }
193
194 static unsigned int od_dbs_timer(struct cpu_dbs_info *cdbs,
195                                  struct dbs_data *dbs_data, bool modify_all)
196 {
197         struct cpufreq_policy *policy = cdbs->shared->policy;
198         unsigned int cpu = policy->cpu;
199         struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
200                         cpu);
201         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
202         int delay = 0, sample_type = dbs_info->sample_type;
203
204         if (!modify_all)
205                 goto max_delay;
206
207         /* Common NORMAL_SAMPLE setup */
208         dbs_info->sample_type = OD_NORMAL_SAMPLE;
209         if (sample_type == OD_SUB_SAMPLE) {
210                 delay = dbs_info->freq_lo_jiffies;
211                 __cpufreq_driver_target(policy, dbs_info->freq_lo,
212                                         CPUFREQ_RELATION_H);
213         } else {
214                 dbs_check_cpu(dbs_data, cpu);
215                 if (dbs_info->freq_lo) {
216                         /* Setup timer for SUB_SAMPLE */
217                         dbs_info->sample_type = OD_SUB_SAMPLE;
218                         delay = dbs_info->freq_hi_jiffies;
219                 }
220         }
221
222 max_delay:
223         if (!delay)
224                 delay = delay_for_sampling_rate(od_tuners->sampling_rate
225                                 * dbs_info->rate_mult);
226
227         return delay;
228 }
229
230 /************************** sysfs interface ************************/
231 static struct common_dbs_data od_dbs_cdata;
232
233 /**
234  * update_sampling_rate - update sampling rate effective immediately if needed.
235  * @new_rate: new sampling rate
236  *
237  * If new rate is smaller than the old, simply updating
238  * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
239  * original sampling_rate was 1 second and the requested new sampling rate is 10
240  * ms because the user needs immediate reaction from ondemand governor, but not
241  * sure if higher frequency will be required or not, then, the governor may
242  * change the sampling rate too late; up to 1 second later. Thus, if we are
243  * reducing the sampling rate, we need to make the new value effective
244  * immediately.
245  */
246 static void update_sampling_rate(struct dbs_data *dbs_data,
247                 unsigned int new_rate)
248 {
249         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
250         int cpu;
251
252         od_tuners->sampling_rate = new_rate = max(new_rate,
253                         dbs_data->min_sampling_rate);
254
255         for_each_online_cpu(cpu) {
256                 struct cpufreq_policy *policy;
257                 struct od_cpu_dbs_info_s *dbs_info;
258                 unsigned long next_sampling, appointed_at;
259
260                 policy = cpufreq_cpu_get(cpu);
261                 if (!policy)
262                         continue;
263                 if (policy->governor != &cpufreq_gov_ondemand) {
264                         cpufreq_cpu_put(policy);
265                         continue;
266                 }
267                 dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
268                 cpufreq_cpu_put(policy);
269
270                 if (!delayed_work_pending(&dbs_info->cdbs.dwork))
271                         continue;
272
273                 next_sampling = jiffies + usecs_to_jiffies(new_rate);
274                 appointed_at = dbs_info->cdbs.dwork.timer.expires;
275
276                 if (time_before(next_sampling, appointed_at)) {
277                         cancel_delayed_work_sync(&dbs_info->cdbs.dwork);
278
279                         gov_queue_work(dbs_data, policy,
280                                        usecs_to_jiffies(new_rate), true);
281
282                 }
283         }
284 }
285
286 static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
287                 size_t count)
288 {
289         unsigned int input;
290         int ret;
291         ret = sscanf(buf, "%u", &input);
292         if (ret != 1)
293                 return -EINVAL;
294
295         update_sampling_rate(dbs_data, input);
296         return count;
297 }
298
299 static ssize_t store_io_is_busy(struct dbs_data *dbs_data, const char *buf,
300                 size_t count)
301 {
302         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
303         unsigned int input;
304         int ret;
305         unsigned int j;
306
307         ret = sscanf(buf, "%u", &input);
308         if (ret != 1)
309                 return -EINVAL;
310         od_tuners->io_is_busy = !!input;
311
312         /* we need to re-evaluate prev_cpu_idle */
313         for_each_online_cpu(j) {
314                 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
315                                                                         j);
316                 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
317                         &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
318         }
319         return count;
320 }
321
322 static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
323                 size_t count)
324 {
325         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
326         unsigned int input;
327         int ret;
328         ret = sscanf(buf, "%u", &input);
329
330         if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
331                         input < MIN_FREQUENCY_UP_THRESHOLD) {
332                 return -EINVAL;
333         }
334
335         od_tuners->up_threshold = input;
336         return count;
337 }
338
339 static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
340                 const char *buf, size_t count)
341 {
342         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
343         unsigned int input, j;
344         int ret;
345         ret = sscanf(buf, "%u", &input);
346
347         if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
348                 return -EINVAL;
349         od_tuners->sampling_down_factor = input;
350
351         /* Reset down sampling multiplier in case it was active */
352         for_each_online_cpu(j) {
353                 struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
354                                 j);
355                 dbs_info->rate_mult = 1;
356         }
357         return count;
358 }
359
360 static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
361                 const char *buf, size_t count)
362 {
363         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
364         unsigned int input;
365         int ret;
366
367         unsigned int j;
368
369         ret = sscanf(buf, "%u", &input);
370         if (ret != 1)
371                 return -EINVAL;
372
373         if (input > 1)
374                 input = 1;
375
376         if (input == od_tuners->ignore_nice_load) { /* nothing to do */
377                 return count;
378         }
379         od_tuners->ignore_nice_load = input;
380
381         /* we need to re-evaluate prev_cpu_idle */
382         for_each_online_cpu(j) {
383                 struct od_cpu_dbs_info_s *dbs_info;
384                 dbs_info = &per_cpu(od_cpu_dbs_info, j);
385                 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
386                         &dbs_info->cdbs.prev_cpu_wall, od_tuners->io_is_busy);
387                 if (od_tuners->ignore_nice_load)
388                         dbs_info->cdbs.prev_cpu_nice =
389                                 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
390
391         }
392         return count;
393 }
394
395 static ssize_t store_powersave_bias(struct dbs_data *dbs_data, const char *buf,
396                 size_t count)
397 {
398         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
399         unsigned int input;
400         int ret;
401         ret = sscanf(buf, "%u", &input);
402
403         if (ret != 1)
404                 return -EINVAL;
405
406         if (input > 1000)
407                 input = 1000;
408
409         od_tuners->powersave_bias = input;
410         ondemand_powersave_bias_init();
411         return count;
412 }
413
414 show_store_one(od, sampling_rate);
415 show_store_one(od, io_is_busy);
416 show_store_one(od, up_threshold);
417 show_store_one(od, sampling_down_factor);
418 show_store_one(od, ignore_nice_load);
419 show_store_one(od, powersave_bias);
420 declare_show_sampling_rate_min(od);
421
422 gov_sys_pol_attr_rw(sampling_rate);
423 gov_sys_pol_attr_rw(io_is_busy);
424 gov_sys_pol_attr_rw(up_threshold);
425 gov_sys_pol_attr_rw(sampling_down_factor);
426 gov_sys_pol_attr_rw(ignore_nice_load);
427 gov_sys_pol_attr_rw(powersave_bias);
428 gov_sys_pol_attr_ro(sampling_rate_min);
429
430 static struct attribute *dbs_attributes_gov_sys[] = {
431         &sampling_rate_min_gov_sys.attr,
432         &sampling_rate_gov_sys.attr,
433         &up_threshold_gov_sys.attr,
434         &sampling_down_factor_gov_sys.attr,
435         &ignore_nice_load_gov_sys.attr,
436         &powersave_bias_gov_sys.attr,
437         &io_is_busy_gov_sys.attr,
438         NULL
439 };
440
441 static struct attribute_group od_attr_group_gov_sys = {
442         .attrs = dbs_attributes_gov_sys,
443         .name = "ondemand",
444 };
445
446 static struct attribute *dbs_attributes_gov_pol[] = {
447         &sampling_rate_min_gov_pol.attr,
448         &sampling_rate_gov_pol.attr,
449         &up_threshold_gov_pol.attr,
450         &sampling_down_factor_gov_pol.attr,
451         &ignore_nice_load_gov_pol.attr,
452         &powersave_bias_gov_pol.attr,
453         &io_is_busy_gov_pol.attr,
454         NULL
455 };
456
457 static struct attribute_group od_attr_group_gov_pol = {
458         .attrs = dbs_attributes_gov_pol,
459         .name = "ondemand",
460 };
461
462 /************************** sysfs end ************************/
463
464 static int od_init(struct dbs_data *dbs_data, bool notify)
465 {
466         struct od_dbs_tuners *tuners;
467         u64 idle_time;
468         int cpu;
469
470         tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
471         if (!tuners) {
472                 pr_err("%s: kzalloc failed\n", __func__);
473                 return -ENOMEM;
474         }
475
476         cpu = get_cpu();
477         idle_time = get_cpu_idle_time_us(cpu, NULL);
478         put_cpu();
479         if (idle_time != -1ULL) {
480                 /* Idle micro accounting is supported. Use finer thresholds */
481                 tuners->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
482                 /*
483                  * In nohz/micro accounting case we set the minimum frequency
484                  * not depending on HZ, but fixed (very low). The deferred
485                  * timer might skip some samples if idle/sleeping as needed.
486                 */
487                 dbs_data->min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
488         } else {
489                 tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
490
491                 /* For correct statistics, we need 10 ticks for each measure */
492                 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
493                         jiffies_to_usecs(10);
494         }
495
496         tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
497         tuners->ignore_nice_load = 0;
498         tuners->powersave_bias = default_powersave_bias;
499         tuners->io_is_busy = should_io_be_busy();
500
501         dbs_data->tuners = tuners;
502         return 0;
503 }
504
505 static void od_exit(struct dbs_data *dbs_data, bool notify)
506 {
507         kfree(dbs_data->tuners);
508 }
509
510 define_get_cpu_dbs_routines(od_cpu_dbs_info);
511
512 static struct od_ops od_ops = {
513         .powersave_bias_init_cpu = ondemand_powersave_bias_init_cpu,
514         .powersave_bias_target = generic_powersave_bias_target,
515         .freq_increase = dbs_freq_increase,
516 };
517
518 static struct common_dbs_data od_dbs_cdata = {
519         .governor = GOV_ONDEMAND,
520         .attr_group_gov_sys = &od_attr_group_gov_sys,
521         .attr_group_gov_pol = &od_attr_group_gov_pol,
522         .get_cpu_cdbs = get_cpu_cdbs,
523         .get_cpu_dbs_info_s = get_cpu_dbs_info_s,
524         .gov_dbs_timer = od_dbs_timer,
525         .gov_check_cpu = od_check_cpu,
526         .gov_ops = &od_ops,
527         .init = od_init,
528         .exit = od_exit,
529         .mutex = __MUTEX_INITIALIZER(od_dbs_cdata.mutex),
530 };
531
532 static void od_set_powersave_bias(unsigned int powersave_bias)
533 {
534         struct cpufreq_policy *policy;
535         struct dbs_data *dbs_data;
536         struct od_dbs_tuners *od_tuners;
537         unsigned int cpu;
538         cpumask_t done;
539
540         default_powersave_bias = powersave_bias;
541         cpumask_clear(&done);
542
543         get_online_cpus();
544         for_each_online_cpu(cpu) {
545                 struct cpu_common_dbs_info *shared;
546
547                 if (cpumask_test_cpu(cpu, &done))
548                         continue;
549
550                 shared = per_cpu(od_cpu_dbs_info, cpu).cdbs.shared;
551                 if (!shared)
552                         continue;
553
554                 policy = shared->policy;
555                 cpumask_or(&done, &done, policy->cpus);
556
557                 if (policy->governor != &cpufreq_gov_ondemand)
558                         continue;
559
560                 dbs_data = policy->governor_data;
561                 od_tuners = dbs_data->tuners;
562                 od_tuners->powersave_bias = default_powersave_bias;
563         }
564         put_online_cpus();
565 }
566
567 void od_register_powersave_bias_handler(unsigned int (*f)
568                 (struct cpufreq_policy *, unsigned int, unsigned int),
569                 unsigned int powersave_bias)
570 {
571         od_ops.powersave_bias_target = f;
572         od_set_powersave_bias(powersave_bias);
573 }
574 EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler);
575
576 void od_unregister_powersave_bias_handler(void)
577 {
578         od_ops.powersave_bias_target = generic_powersave_bias_target;
579         od_set_powersave_bias(0);
580 }
581 EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler);
582
583 static int od_cpufreq_governor_dbs(struct cpufreq_policy *policy,
584                 unsigned int event)
585 {
586         return cpufreq_governor_dbs(policy, &od_dbs_cdata, event);
587 }
588
589 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
590 static
591 #endif
592 struct cpufreq_governor cpufreq_gov_ondemand = {
593         .name                   = "ondemand",
594         .governor               = od_cpufreq_governor_dbs,
595         .max_transition_latency = TRANSITION_LATENCY_LIMIT,
596         .owner                  = THIS_MODULE,
597 };
598
599 static int __init cpufreq_gov_dbs_init(void)
600 {
601         return cpufreq_register_governor(&cpufreq_gov_ondemand);
602 }
603
604 static void __exit cpufreq_gov_dbs_exit(void)
605 {
606         cpufreq_unregister_governor(&cpufreq_gov_ondemand);
607 }
608
609 MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
610 MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
611 MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
612         "Low Latency Frequency Transition capable processors");
613 MODULE_LICENSE("GPL");
614
615 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
616 fs_initcall(cpufreq_gov_dbs_init);
617 #else
618 module_init(cpufreq_gov_dbs_init);
619 #endif
620 module_exit(cpufreq_gov_dbs_exit);