2 * drivers/cpufreq/cpufreq_governor.c
4 * CPUFREQ governors common code
6 * Copyright (C) 2001 Russell King
7 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
8 * (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
9 * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
10 * (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 #include <asm/cputime.h>
20 #include <linux/cpufreq.h>
21 #include <linux/cpumask.h>
22 #include <linux/export.h>
23 #include <linux/kernel_stat.h>
24 #include <linux/mutex.h>
25 #include <linux/slab.h>
26 #include <linux/tick.h>
27 #include <linux/types.h>
28 #include <linux/workqueue.h>
30 #include "cpufreq_governor.h"
32 static struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
34 if (have_governor_per_policy())
37 return cpufreq_global_kobject;
40 static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
42 if (have_governor_per_policy())
43 return dbs_data->cdata->attr_group_gov_pol;
45 return dbs_data->cdata->attr_group_gov_sys;
48 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
54 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
56 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
57 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
58 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
59 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
60 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
61 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
63 idle_time = cur_wall_time - busy_time;
65 *wall = cputime_to_usecs(cur_wall_time);
67 return cputime_to_usecs(idle_time);
70 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
72 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
74 if (idle_time == -1ULL)
75 return get_cpu_idle_time_jiffy(cpu, wall);
77 idle_time += get_cpu_iowait_time_us(cpu, wall);
81 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
83 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
85 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
86 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
87 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
88 struct cpufreq_policy *policy;
89 unsigned int max_load = 0;
90 unsigned int ignore_nice;
93 if (dbs_data->cdata->governor == GOV_ONDEMAND)
94 ignore_nice = od_tuners->ignore_nice;
96 ignore_nice = cs_tuners->ignore_nice;
98 policy = cdbs->cur_policy;
100 /* Get Absolute Load (in terms of freq for ondemand gov) */
101 for_each_cpu(j, policy->cpus) {
102 struct cpu_dbs_common_info *j_cdbs;
103 u64 cur_wall_time, cur_idle_time;
104 unsigned int idle_time, wall_time;
108 j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
111 * For the purpose of ondemand, waiting for disk IO is
112 * an indication that you're performance critical, and
113 * not that the system is actually idle. So do not add
114 * the iowait time to the cpu idle time.
116 if (dbs_data->cdata->governor == GOV_ONDEMAND)
117 io_busy = od_tuners->io_is_busy;
118 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
120 wall_time = (unsigned int)
121 (cur_wall_time - j_cdbs->prev_cpu_wall);
122 j_cdbs->prev_cpu_wall = cur_wall_time;
124 idle_time = (unsigned int)
125 (cur_idle_time - j_cdbs->prev_cpu_idle);
126 j_cdbs->prev_cpu_idle = cur_idle_time;
130 unsigned long cur_nice_jiffies;
132 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
135 * Assumption: nice time between sampling periods will
136 * be less than 2^32 jiffies for 32 bit sys
138 cur_nice_jiffies = (unsigned long)
139 cputime64_to_jiffies64(cur_nice);
141 cdbs->prev_cpu_nice =
142 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
143 idle_time += jiffies_to_usecs(cur_nice_jiffies);
146 if (unlikely(!wall_time || wall_time < idle_time))
149 load = 100 * (wall_time - idle_time) / wall_time;
151 if (dbs_data->cdata->governor == GOV_ONDEMAND) {
152 int freq_avg = __cpufreq_driver_getavg(policy, j);
154 freq_avg = policy->cur;
163 dbs_data->cdata->gov_check_cpu(cpu, max_load);
165 EXPORT_SYMBOL_GPL(dbs_check_cpu);
167 static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
170 struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
172 mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
175 void gov_queue_work(struct dbs_data *dbs_data, struct cpufreq_policy *policy,
176 unsigned int delay, bool all_cpus)
181 __gov_queue_work(smp_processor_id(), dbs_data, delay);
183 for_each_cpu(i, policy->cpus)
184 __gov_queue_work(i, dbs_data, delay);
187 EXPORT_SYMBOL_GPL(gov_queue_work);
189 static inline void gov_cancel_work(struct dbs_data *dbs_data,
190 struct cpufreq_policy *policy)
192 struct cpu_dbs_common_info *cdbs;
195 for_each_cpu(i, policy->cpus) {
196 cdbs = dbs_data->cdata->get_cpu_cdbs(i);
197 cancel_delayed_work_sync(&cdbs->work);
201 /* Will return if we need to evaluate cpu load again or not */
202 bool need_load_eval(struct cpu_dbs_common_info *cdbs,
203 unsigned int sampling_rate)
205 if (policy_is_shared(cdbs->cur_policy)) {
206 ktime_t time_now = ktime_get();
207 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
209 /* Do nothing if we recently have sampled */
210 if (delta_us < (s64)(sampling_rate / 2))
213 cdbs->time_stamp = time_now;
218 EXPORT_SYMBOL_GPL(need_load_eval);
220 static void set_sampling_rate(struct dbs_data *dbs_data,
221 unsigned int sampling_rate)
223 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
224 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
225 cs_tuners->sampling_rate = sampling_rate;
227 struct od_dbs_tuners *od_tuners = dbs_data->tuners;
228 od_tuners->sampling_rate = sampling_rate;
232 int cpufreq_governor_dbs(struct cpufreq_policy *policy,
233 struct common_dbs_data *cdata, unsigned int event)
235 struct dbs_data *dbs_data;
236 struct od_cpu_dbs_info_s *od_dbs_info = NULL;
237 struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
238 struct od_ops *od_ops = NULL;
239 struct od_dbs_tuners *od_tuners = NULL;
240 struct cs_dbs_tuners *cs_tuners = NULL;
241 struct cpu_dbs_common_info *cpu_cdbs;
242 unsigned int sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
246 if (have_governor_per_policy())
247 dbs_data = policy->governor_data;
249 dbs_data = cdata->gdbs_data;
251 WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
254 case CPUFREQ_GOV_POLICY_INIT:
255 if (have_governor_per_policy()) {
257 } else if (dbs_data) {
258 policy->governor_data = dbs_data;
262 dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
264 pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
268 dbs_data->cdata = cdata;
269 rc = cdata->init(dbs_data);
271 pr_err("%s: POLICY_INIT: init() failed\n", __func__);
276 rc = sysfs_create_group(get_governor_parent_kobj(policy),
277 get_sysfs_attr(dbs_data));
279 cdata->exit(dbs_data);
284 policy->governor_data = dbs_data;
286 /* policy latency is in nS. Convert it to uS first */
287 latency = policy->cpuinfo.transition_latency / 1000;
291 /* Bring kernel and HW constraints together */
292 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
293 MIN_LATENCY_MULTIPLIER * latency);
294 set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
295 latency * LATENCY_MULTIPLIER));
297 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
298 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
300 cpufreq_register_notifier(cs_ops->notifier_block,
301 CPUFREQ_TRANSITION_NOTIFIER);
304 if (!have_governor_per_policy())
305 cdata->gdbs_data = dbs_data;
308 case CPUFREQ_GOV_POLICY_EXIT:
309 if ((policy->governor->initialized == 1) ||
310 have_governor_per_policy()) {
311 sysfs_remove_group(get_governor_parent_kobj(policy),
312 get_sysfs_attr(dbs_data));
314 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
315 struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
317 cpufreq_unregister_notifier(cs_ops->notifier_block,
318 CPUFREQ_TRANSITION_NOTIFIER);
321 cdata->exit(dbs_data);
323 cdata->gdbs_data = NULL;
326 policy->governor_data = NULL;
330 cpu_cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
332 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
333 cs_tuners = dbs_data->tuners;
334 cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
335 sampling_rate = cs_tuners->sampling_rate;
336 ignore_nice = cs_tuners->ignore_nice;
338 od_tuners = dbs_data->tuners;
339 od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
340 sampling_rate = od_tuners->sampling_rate;
341 ignore_nice = od_tuners->ignore_nice;
342 od_ops = dbs_data->cdata->gov_ops;
343 io_busy = od_tuners->io_is_busy;
347 case CPUFREQ_GOV_START:
351 mutex_lock(&dbs_data->mutex);
353 for_each_cpu(j, policy->cpus) {
354 struct cpu_dbs_common_info *j_cdbs =
355 dbs_data->cdata->get_cpu_cdbs(j);
358 j_cdbs->cur_policy = policy;
359 j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
360 &j_cdbs->prev_cpu_wall, io_busy);
362 j_cdbs->prev_cpu_nice =
363 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
365 mutex_init(&j_cdbs->timer_mutex);
366 INIT_DEFERRABLE_WORK(&j_cdbs->work,
367 dbs_data->cdata->gov_dbs_timer);
371 * conservative does not implement micro like ondemand
372 * governor, thus we are bound to jiffes/HZ
374 if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
375 cs_dbs_info->down_skip = 0;
376 cs_dbs_info->enable = 1;
377 cs_dbs_info->requested_freq = policy->cur;
379 od_dbs_info->rate_mult = 1;
380 od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
381 od_ops->powersave_bias_init_cpu(cpu);
384 mutex_unlock(&dbs_data->mutex);
386 /* Initiate timer time stamp */
387 cpu_cdbs->time_stamp = ktime_get();
389 gov_queue_work(dbs_data, policy,
390 delay_for_sampling_rate(sampling_rate), true);
393 case CPUFREQ_GOV_STOP:
394 if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
395 cs_dbs_info->enable = 0;
397 gov_cancel_work(dbs_data, policy);
399 mutex_lock(&dbs_data->mutex);
400 mutex_destroy(&cpu_cdbs->timer_mutex);
402 mutex_unlock(&dbs_data->mutex);
406 case CPUFREQ_GOV_LIMITS:
407 mutex_lock(&cpu_cdbs->timer_mutex);
408 if (policy->max < cpu_cdbs->cur_policy->cur)
409 __cpufreq_driver_target(cpu_cdbs->cur_policy,
410 policy->max, CPUFREQ_RELATION_H);
411 else if (policy->min > cpu_cdbs->cur_policy->cur)
412 __cpufreq_driver_target(cpu_cdbs->cur_policy,
413 policy->min, CPUFREQ_RELATION_L);
414 dbs_check_cpu(dbs_data, cpu);
415 mutex_unlock(&cpu_cdbs->timer_mutex);
420 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);