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Dave Jonesb9170832005-05-31 19:03:47 -07001/*
2 * drivers/cpufreq/cpufreq_conservative.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * Jun Nakajima <jun.nakajima@intel.com>
Alexander Clouter11a80a9c762009-02-13 19:01:01 +00007 * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
Dave Jonesb9170832005-05-31 19:03:47 -07008 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
Dave Jonesb9170832005-05-31 19:03:47 -070014#include <linux/cpufreq.h>
Viresh Kumar4471a342012-10-26 00:47:42 +020015#include <linux/init.h>
16#include <linux/kernel.h>
Dave Jonesb9170832005-05-31 19:03:47 -070017#include <linux/kernel_stat.h>
Viresh Kumar4471a342012-10-26 00:47:42 +020018#include <linux/kobject.h>
19#include <linux/module.h>
akpm@osdl.org3fc54d32006-01-13 15:54:22 -080020#include <linux/mutex.h>
Viresh Kumar4471a342012-10-26 00:47:42 +020021#include <linux/notifier.h>
22#include <linux/percpu-defs.h>
23#include <linux/sysfs.h>
24#include <linux/types.h>
Alexander Clouter8e677ce2009-02-13 19:02:34 +000025
Viresh Kumar4471a342012-10-26 00:47:42 +020026#include "cpufreq_governor.h"
Dave Jonesb9170832005-05-31 19:03:47 -070027
Viresh Kumar4471a342012-10-26 00:47:42 +020028/* Conservative governor macors */
Dave Jonesb9170832005-05-31 19:03:47 -070029#define DEF_FREQUENCY_UP_THRESHOLD (80)
Dave Jonesb9170832005-05-31 19:03:47 -070030#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
Alexander Clouter2c906b32006-03-22 09:54:10 +000031#define DEF_SAMPLING_DOWN_FACTOR (1)
32#define MAX_SAMPLING_DOWN_FACTOR (10)
Dave Jonesb9170832005-05-31 19:03:47 -070033
Viresh Kumar4471a342012-10-26 00:47:42 +020034static struct dbs_data cs_dbs_data;
35static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);
Dave Jonesb9170832005-05-31 19:03:47 -070036
Viresh Kumar4471a342012-10-26 00:47:42 +020037static struct cs_dbs_tuners cs_tuners = {
Dave Jones18a72472007-10-22 16:49:09 -040038 .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
39 .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
40 .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
41 .ignore_nice = 0,
42 .freq_step = 5,
Dave Jonesb9170832005-05-31 19:03:47 -070043};
44
Viresh Kumar4471a342012-10-26 00:47:42 +020045/*
46 * Every sampling_rate, we check, if current idle time is less than 20%
47 * (default), then we try to increase frequency Every sampling_rate *
48 * sampling_down_factor, we check, if current idle time is more than 80%, then
49 * we try to decrease frequency
50 *
51 * Any frequency increase takes it to the maximum frequency. Frequency reduction
52 * happens at minimum steps of 5% (default) of maximum frequency
53 */
54static void cs_check_cpu(int cpu, unsigned int load)
Elias Oltmannsa8d7c3b2007-10-22 09:50:13 +020055{
Viresh Kumar4471a342012-10-26 00:47:42 +020056 struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu);
57 struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
58 unsigned int freq_target;
Alexander Clouterf407a082009-02-13 19:01:51 +000059
60 /*
Viresh Kumar4471a342012-10-26 00:47:42 +020061 * break out if we 'cannot' reduce the speed as the user might
62 * want freq_step to be zero
63 */
64 if (cs_tuners.freq_step == 0)
65 return;
66
67 /* Check for frequency increase */
68 if (load > cs_tuners.up_threshold) {
69 dbs_info->down_skip = 0;
70
71 /* if we are already at full speed then break out early */
72 if (dbs_info->requested_freq == policy->max)
73 return;
74
75 freq_target = (cs_tuners.freq_step * policy->max) / 100;
76
77 /* max freq cannot be less than 100. But who knows.... */
78 if (unlikely(freq_target == 0))
79 freq_target = 5;
80
81 dbs_info->requested_freq += freq_target;
82 if (dbs_info->requested_freq > policy->max)
83 dbs_info->requested_freq = policy->max;
84
85 __cpufreq_driver_target(policy, dbs_info->requested_freq,
86 CPUFREQ_RELATION_H);
87 return;
88 }
89
90 /*
91 * The optimal frequency is the frequency that is the lowest that can
92 * support the current CPU usage without triggering the up policy. To be
93 * safe, we focus 10 points under the threshold.
94 */
95 if (load < (cs_tuners.down_threshold - 10)) {
96 freq_target = (cs_tuners.freq_step * policy->max) / 100;
97
98 dbs_info->requested_freq -= freq_target;
99 if (dbs_info->requested_freq < policy->min)
100 dbs_info->requested_freq = policy->min;
101
102 /*
103 * if we cannot reduce the frequency anymore, break out early
104 */
105 if (policy->cur == policy->min)
106 return;
107
108 __cpufreq_driver_target(policy, dbs_info->requested_freq,
109 CPUFREQ_RELATION_H);
110 return;
111 }
112}
113
114static void cs_dbs_timer(struct work_struct *work)
115{
116 struct cs_cpu_dbs_info_s *dbs_info = container_of(work,
117 struct cs_cpu_dbs_info_s, cdbs.work.work);
118 unsigned int cpu = dbs_info->cdbs.cpu;
119 int delay = delay_for_sampling_rate(cs_tuners.sampling_rate);
120
121 mutex_lock(&dbs_info->cdbs.timer_mutex);
122
123 dbs_check_cpu(&cs_dbs_data, cpu);
124
125 schedule_delayed_work_on(cpu, &dbs_info->cdbs.work, delay);
126 mutex_unlock(&dbs_info->cdbs.timer_mutex);
127}
128
129static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
130 void *data)
131{
132 struct cpufreq_freqs *freq = data;
133 struct cs_cpu_dbs_info_s *dbs_info =
134 &per_cpu(cs_cpu_dbs_info, freq->cpu);
135 struct cpufreq_policy *policy;
136
137 if (!dbs_info->enable)
138 return 0;
139
140 policy = dbs_info->cdbs.cur_policy;
141
142 /*
143 * we only care if our internally tracked freq moves outside the 'valid'
144 * ranges of freqency available to us otherwise we do not change it
Alexander Clouterf407a082009-02-13 19:01:51 +0000145 */
Viresh Kumar4471a342012-10-26 00:47:42 +0200146 if (dbs_info->requested_freq > policy->max
147 || dbs_info->requested_freq < policy->min)
148 dbs_info->requested_freq = freq->new;
Elias Oltmannsa8d7c3b2007-10-22 09:50:13 +0200149
150 return 0;
151}
152
Dave Jonesb9170832005-05-31 19:03:47 -0700153/************************** sysfs interface ************************/
Thomas Renninger49b015c2009-10-01 19:49:28 +0200154static ssize_t show_sampling_rate_min(struct kobject *kobj,
155 struct attribute *attr, char *buf)
Dave Jonesb9170832005-05-31 19:03:47 -0700156{
Viresh Kumar4471a342012-10-26 00:47:42 +0200157 return sprintf(buf, "%u\n", cs_dbs_data.min_sampling_rate);
Dave Jonesb9170832005-05-31 19:03:47 -0700158}
159
Thomas Renninger49b015c2009-10-01 19:49:28 +0200160static ssize_t store_sampling_down_factor(struct kobject *a,
161 struct attribute *b,
162 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700163{
164 unsigned int input;
165 int ret;
Dave Jones9acef482009-01-18 01:39:51 -0500166 ret = sscanf(buf, "%u", &input);
Alexander Clouter8e677ce2009-02-13 19:02:34 +0000167
Alexander Clouter2c906b32006-03-22 09:54:10 +0000168 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
Dave Jonesb9170832005-05-31 19:03:47 -0700169 return -EINVAL;
170
Viresh Kumar4471a342012-10-26 00:47:42 +0200171 cs_tuners.sampling_down_factor = input;
Dave Jonesb9170832005-05-31 19:03:47 -0700172 return count;
173}
174
Thomas Renninger49b015c2009-10-01 19:49:28 +0200175static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
176 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700177{
178 unsigned int input;
179 int ret;
Dave Jones9acef482009-01-18 01:39:51 -0500180 ret = sscanf(buf, "%u", &input);
Dave Jonesb9170832005-05-31 19:03:47 -0700181
Alexander Clouter8e677ce2009-02-13 19:02:34 +0000182 if (ret != 1)
Dave Jonesb9170832005-05-31 19:03:47 -0700183 return -EINVAL;
Alexander Clouter8e677ce2009-02-13 19:02:34 +0000184
Viresh Kumar4471a342012-10-26 00:47:42 +0200185 cs_tuners.sampling_rate = max(input, cs_dbs_data.min_sampling_rate);
Dave Jonesb9170832005-05-31 19:03:47 -0700186 return count;
187}
188
Thomas Renninger49b015c2009-10-01 19:49:28 +0200189static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
190 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700191{
192 unsigned int input;
193 int ret;
Dave Jones9acef482009-01-18 01:39:51 -0500194 ret = sscanf(buf, "%u", &input);
Dave Jonesb9170832005-05-31 19:03:47 -0700195
Viresh Kumar4471a342012-10-26 00:47:42 +0200196 if (ret != 1 || input > 100 || input <= cs_tuners.down_threshold)
Dave Jonesb9170832005-05-31 19:03:47 -0700197 return -EINVAL;
Dave Jonesb9170832005-05-31 19:03:47 -0700198
Viresh Kumar4471a342012-10-26 00:47:42 +0200199 cs_tuners.up_threshold = input;
Dave Jonesb9170832005-05-31 19:03:47 -0700200 return count;
201}
202
Thomas Renninger49b015c2009-10-01 19:49:28 +0200203static ssize_t store_down_threshold(struct kobject *a, struct attribute *b,
204 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700205{
206 unsigned int input;
207 int ret;
Dave Jones9acef482009-01-18 01:39:51 -0500208 ret = sscanf(buf, "%u", &input);
Dave Jonesb9170832005-05-31 19:03:47 -0700209
Alexander Clouter8e677ce2009-02-13 19:02:34 +0000210 /* cannot be lower than 11 otherwise freq will not fall */
211 if (ret != 1 || input < 11 || input > 100 ||
Viresh Kumar4471a342012-10-26 00:47:42 +0200212 input >= cs_tuners.up_threshold)
Dave Jonesb9170832005-05-31 19:03:47 -0700213 return -EINVAL;
Dave Jonesb9170832005-05-31 19:03:47 -0700214
Viresh Kumar4471a342012-10-26 00:47:42 +0200215 cs_tuners.down_threshold = input;
Dave Jonesb9170832005-05-31 19:03:47 -0700216 return count;
217}
218
Thomas Renninger49b015c2009-10-01 19:49:28 +0200219static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
220 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700221{
Viresh Kumar4471a342012-10-26 00:47:42 +0200222 unsigned int input, j;
Dave Jonesb9170832005-05-31 19:03:47 -0700223 int ret;
224
Dave Jones18a72472007-10-22 16:49:09 -0400225 ret = sscanf(buf, "%u", &input);
226 if (ret != 1)
Dave Jonesb9170832005-05-31 19:03:47 -0700227 return -EINVAL;
228
Dave Jones18a72472007-10-22 16:49:09 -0400229 if (input > 1)
Dave Jonesb9170832005-05-31 19:03:47 -0700230 input = 1;
Dave Jones18a72472007-10-22 16:49:09 -0400231
Viresh Kumar4471a342012-10-26 00:47:42 +0200232 if (input == cs_tuners.ignore_nice) /* nothing to do */
Dave Jonesb9170832005-05-31 19:03:47 -0700233 return count;
Thomas Renninger326c86d2011-03-03 21:31:27 +0100234
Viresh Kumar4471a342012-10-26 00:47:42 +0200235 cs_tuners.ignore_nice = input;
Dave Jonesb9170832005-05-31 19:03:47 -0700236
Alexander Clouter8e677ce2009-02-13 19:02:34 +0000237 /* we need to re-evaluate prev_cpu_idle */
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700238 for_each_online_cpu(j) {
Viresh Kumar4471a342012-10-26 00:47:42 +0200239 struct cs_cpu_dbs_info_s *dbs_info;
Tejun Heo245b2e72009-06-24 15:13:48 +0900240 dbs_info = &per_cpu(cs_cpu_dbs_info, j);
Viresh Kumar4471a342012-10-26 00:47:42 +0200241 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
242 &dbs_info->cdbs.prev_cpu_wall);
243 if (cs_tuners.ignore_nice)
244 dbs_info->cdbs.prev_cpu_nice =
245 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
Dave Jonesb9170832005-05-31 19:03:47 -0700246 }
Dave Jonesb9170832005-05-31 19:03:47 -0700247 return count;
248}
249
Thomas Renninger49b015c2009-10-01 19:49:28 +0200250static ssize_t store_freq_step(struct kobject *a, struct attribute *b,
251 const char *buf, size_t count)
Dave Jonesb9170832005-05-31 19:03:47 -0700252{
253 unsigned int input;
254 int ret;
Dave Jones18a72472007-10-22 16:49:09 -0400255 ret = sscanf(buf, "%u", &input);
Dave Jonesb9170832005-05-31 19:03:47 -0700256
Dave Jones18a72472007-10-22 16:49:09 -0400257 if (ret != 1)
Dave Jonesb9170832005-05-31 19:03:47 -0700258 return -EINVAL;
259
Dave Jones18a72472007-10-22 16:49:09 -0400260 if (input > 100)
Dave Jonesb9170832005-05-31 19:03:47 -0700261 input = 100;
Dave Jones18a72472007-10-22 16:49:09 -0400262
Viresh Kumar4471a342012-10-26 00:47:42 +0200263 /*
264 * no need to test here if freq_step is zero as the user might actually
265 * want this, they would be crazy though :)
266 */
267 cs_tuners.freq_step = input;
Dave Jonesb9170832005-05-31 19:03:47 -0700268 return count;
269}
270
Viresh Kumar4471a342012-10-26 00:47:42 +0200271show_one(cs, sampling_rate, sampling_rate);
272show_one(cs, sampling_down_factor, sampling_down_factor);
273show_one(cs, up_threshold, up_threshold);
274show_one(cs, down_threshold, down_threshold);
275show_one(cs, ignore_nice_load, ignore_nice);
276show_one(cs, freq_step, freq_step);
277
Borislav Petkov6dad2a22010-03-31 21:56:46 +0200278define_one_global_rw(sampling_rate);
279define_one_global_rw(sampling_down_factor);
280define_one_global_rw(up_threshold);
281define_one_global_rw(down_threshold);
282define_one_global_rw(ignore_nice_load);
283define_one_global_rw(freq_step);
Viresh Kumar4471a342012-10-26 00:47:42 +0200284define_one_global_ro(sampling_rate_min);
Dave Jonesb9170832005-05-31 19:03:47 -0700285
Dave Jones9acef482009-01-18 01:39:51 -0500286static struct attribute *dbs_attributes[] = {
Dave Jonesb9170832005-05-31 19:03:47 -0700287 &sampling_rate_min.attr,
288 &sampling_rate.attr,
289 &sampling_down_factor.attr,
290 &up_threshold.attr,
291 &down_threshold.attr,
Alexander Clouter001893c2005-12-01 01:09:25 -0800292 &ignore_nice_load.attr,
Dave Jonesb9170832005-05-31 19:03:47 -0700293 &freq_step.attr,
294 NULL
295};
296
Viresh Kumar4471a342012-10-26 00:47:42 +0200297static struct attribute_group cs_attr_group = {
Dave Jonesb9170832005-05-31 19:03:47 -0700298 .attrs = dbs_attributes,
299 .name = "conservative",
300};
301
302/************************** sysfs end ************************/
303
Viresh Kumar4471a342012-10-26 00:47:42 +0200304define_get_cpu_dbs_routines(cs_cpu_dbs_info);
Dave Jonesb9170832005-05-31 19:03:47 -0700305
Viresh Kumar4471a342012-10-26 00:47:42 +0200306static struct notifier_block cs_cpufreq_notifier_block = {
307 .notifier_call = dbs_cpufreq_notifier,
308};
Dave Jonesb9170832005-05-31 19:03:47 -0700309
Viresh Kumar4471a342012-10-26 00:47:42 +0200310static struct cs_ops cs_ops = {
311 .notifier_block = &cs_cpufreq_notifier_block,
312};
Alexander Clouter08a28e22006-03-22 09:59:16 +0000313
Viresh Kumar4471a342012-10-26 00:47:42 +0200314static struct dbs_data cs_dbs_data = {
315 .governor = GOV_CONSERVATIVE,
316 .attr_group = &cs_attr_group,
317 .tuners = &cs_tuners,
318 .get_cpu_cdbs = get_cpu_cdbs,
319 .get_cpu_dbs_info_s = get_cpu_dbs_info_s,
320 .gov_dbs_timer = cs_dbs_timer,
321 .gov_check_cpu = cs_check_cpu,
322 .gov_ops = &cs_ops,
323};
Dave Jonesb9170832005-05-31 19:03:47 -0700324
Viresh Kumar4471a342012-10-26 00:47:42 +0200325static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy,
Dave Jonesb9170832005-05-31 19:03:47 -0700326 unsigned int event)
327{
Viresh Kumar4471a342012-10-26 00:47:42 +0200328 return cpufreq_governor_dbs(&cs_dbs_data, policy, event);
Dave Jonesb9170832005-05-31 19:03:47 -0700329}
330
Sven Wegenerc4d14bc2008-09-20 16:50:08 +0200331#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
332static
333#endif
Thomas Renninger1c256242007-10-02 13:28:12 -0700334struct cpufreq_governor cpufreq_gov_conservative = {
335 .name = "conservative",
Viresh Kumar4471a342012-10-26 00:47:42 +0200336 .governor = cs_cpufreq_governor_dbs,
Thomas Renninger1c256242007-10-02 13:28:12 -0700337 .max_transition_latency = TRANSITION_LATENCY_LIMIT,
338 .owner = THIS_MODULE,
Dave Jonesb9170832005-05-31 19:03:47 -0700339};
340
341static int __init cpufreq_gov_dbs_init(void)
342{
Viresh Kumar4471a342012-10-26 00:47:42 +0200343 mutex_init(&cs_dbs_data.mutex);
Tejun Heo57df5572011-01-26 12:12:50 +0100344 return cpufreq_register_governor(&cpufreq_gov_conservative);
Dave Jonesb9170832005-05-31 19:03:47 -0700345}
346
347static void __exit cpufreq_gov_dbs_exit(void)
348{
Thomas Renninger1c256242007-10-02 13:28:12 -0700349 cpufreq_unregister_governor(&cpufreq_gov_conservative);
Dave Jonesb9170832005-05-31 19:03:47 -0700350}
351
Alexander Clouter11a80a9c762009-02-13 19:01:01 +0000352MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
Dave Jones9acef482009-01-18 01:39:51 -0500353MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
Dave Jonesb9170832005-05-31 19:03:47 -0700354 "Low Latency Frequency Transition capable processors "
355 "optimised for use in a battery environment");
Dave Jones9acef482009-01-18 01:39:51 -0500356MODULE_LICENSE("GPL");
Dave Jonesb9170832005-05-31 19:03:47 -0700357
Johannes Weiner69157192008-01-17 15:21:08 -0800358#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
359fs_initcall(cpufreq_gov_dbs_init);
360#else
Dave Jonesb9170832005-05-31 19:03:47 -0700361module_init(cpufreq_gov_dbs_init);
Johannes Weiner69157192008-01-17 15:21:08 -0800362#endif
Dave Jonesb9170832005-05-31 19:03:47 -0700363module_exit(cpufreq_gov_dbs_exit);