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b9170836 DJ |
1 | /* |
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> | |
11a80a9c | 7 | * (C) 2009 Alexander Clouter <alex@digriz.org.uk> |
b9170836 DJ |
8 | * |
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 | ||
4d5dcc42 | 14 | #include <linux/slab.h> |
4471a34f | 15 | #include "cpufreq_governor.h" |
b9170836 | 16 | |
c88883cd | 17 | /* Conservative governor macros */ |
b9170836 | 18 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
b9170836 | 19 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
98765847 | 20 | #define DEF_FREQUENCY_STEP (5) |
2c906b31 AC |
21 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
22 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 | 23 | |
4471a34f | 24 | static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); |
b9170836 | 25 | |
98765847 SK |
26 | static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, |
27 | struct cpufreq_policy *policy) | |
28 | { | |
29 | unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100; | |
30 | ||
31 | /* max freq cannot be less than 100. But who knows... */ | |
32 | if (unlikely(freq_target == 0)) | |
33 | freq_target = DEF_FREQUENCY_STEP; | |
34 | ||
35 | return freq_target; | |
36 | } | |
37 | ||
4471a34f VK |
38 | /* |
39 | * Every sampling_rate, we check, if current idle time is less than 20% | |
7af1c056 SK |
40 | * (default), then we try to increase frequency. Every sampling_rate * |
41 | * sampling_down_factor, we check, if current idle time is more than 80% | |
42 | * (default), then we try to decrease frequency | |
4471a34f VK |
43 | * |
44 | * Any frequency increase takes it to the maximum frequency. Frequency reduction | |
45 | * happens at minimum steps of 5% (default) of maximum frequency | |
46 | */ | |
4cccf755 | 47 | static unsigned int cs_dbs_timer(struct cpufreq_policy *policy) |
a8d7c3bc | 48 | { |
4cccf755 | 49 | struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, policy->cpu); |
bc505475 RW |
50 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
51 | struct dbs_data *dbs_data = policy_dbs->dbs_data; | |
4d5dcc42 | 52 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
4cccf755 | 53 | unsigned int load = dbs_update(policy); |
4471a34f VK |
54 | |
55 | /* | |
56 | * break out if we 'cannot' reduce the speed as the user might | |
57 | * want freq_step to be zero | |
58 | */ | |
4d5dcc42 | 59 | if (cs_tuners->freq_step == 0) |
4cccf755 | 60 | goto out; |
4471a34f VK |
61 | |
62 | /* Check for frequency increase */ | |
ff4b1789 | 63 | if (load > dbs_data->up_threshold) { |
4471a34f VK |
64 | dbs_info->down_skip = 0; |
65 | ||
66 | /* if we are already at full speed then break out early */ | |
67 | if (dbs_info->requested_freq == policy->max) | |
4cccf755 | 68 | goto out; |
4471a34f | 69 | |
98765847 | 70 | dbs_info->requested_freq += get_freq_target(cs_tuners, policy); |
a8d7c3bc | 71 | |
6d7bcb14 XC |
72 | if (dbs_info->requested_freq > policy->max) |
73 | dbs_info->requested_freq = policy->max; | |
74 | ||
4471a34f VK |
75 | __cpufreq_driver_target(policy, dbs_info->requested_freq, |
76 | CPUFREQ_RELATION_H); | |
4cccf755 | 77 | goto out; |
4471a34f VK |
78 | } |
79 | ||
7af1c056 | 80 | /* if sampling_down_factor is active break out early */ |
ff4b1789 | 81 | if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
4cccf755 | 82 | goto out; |
7af1c056 SK |
83 | dbs_info->down_skip = 0; |
84 | ||
27ed3cd2 SK |
85 | /* Check for frequency decrease */ |
86 | if (load < cs_tuners->down_threshold) { | |
3baa976a | 87 | unsigned int freq_target; |
4471a34f VK |
88 | /* |
89 | * if we cannot reduce the frequency anymore, break out early | |
90 | */ | |
91 | if (policy->cur == policy->min) | |
4cccf755 | 92 | goto out; |
4471a34f | 93 | |
3baa976a XC |
94 | freq_target = get_freq_target(cs_tuners, policy); |
95 | if (dbs_info->requested_freq > freq_target) | |
96 | dbs_info->requested_freq -= freq_target; | |
97 | else | |
98 | dbs_info->requested_freq = policy->min; | |
ad529a9c | 99 | |
4471a34f | 100 | __cpufreq_driver_target(policy, dbs_info->requested_freq, |
fed573d5 | 101 | CPUFREQ_RELATION_L); |
4471a34f | 102 | } |
43e0ee36 | 103 | |
4cccf755 | 104 | out: |
07aa4402 | 105 | return dbs_data->sampling_rate; |
66df2a01 FB |
106 | } |
107 | ||
4471a34f | 108 | static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
af926185 | 109 | void *data); |
a8d7c3bc | 110 | |
8e0484d2 VK |
111 | static struct notifier_block cs_cpufreq_notifier_block = { |
112 | .notifier_call = dbs_cpufreq_notifier, | |
113 | }; | |
114 | ||
b9170836 | 115 | /************************** sysfs interface ************************/ |
7bdad34d | 116 | static struct dbs_governor cs_dbs_gov; |
b9170836 | 117 | |
4d5dcc42 VK |
118 | static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, |
119 | const char *buf, size_t count) | |
b9170836 DJ |
120 | { |
121 | unsigned int input; | |
122 | int ret; | |
9acef487 | 123 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 124 | |
2c906b31 | 125 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
126 | return -EINVAL; |
127 | ||
ff4b1789 | 128 | dbs_data->sampling_down_factor = input; |
b9170836 DJ |
129 | return count; |
130 | } | |
131 | ||
4d5dcc42 VK |
132 | static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf, |
133 | size_t count) | |
b9170836 | 134 | { |
4d5dcc42 | 135 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
136 | unsigned int input; |
137 | int ret; | |
9acef487 | 138 | ret = sscanf(buf, "%u", &input); |
b9170836 | 139 | |
4d5dcc42 | 140 | if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
b9170836 | 141 | return -EINVAL; |
b9170836 | 142 | |
ff4b1789 | 143 | dbs_data->up_threshold = input; |
b9170836 DJ |
144 | return count; |
145 | } | |
146 | ||
4d5dcc42 VK |
147 | static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf, |
148 | size_t count) | |
b9170836 | 149 | { |
4d5dcc42 | 150 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
151 | unsigned int input; |
152 | int ret; | |
9acef487 | 153 | ret = sscanf(buf, "%u", &input); |
b9170836 | 154 | |
8e677ce8 AC |
155 | /* cannot be lower than 11 otherwise freq will not fall */ |
156 | if (ret != 1 || input < 11 || input > 100 || | |
ff4b1789 | 157 | input >= dbs_data->up_threshold) |
b9170836 | 158 | return -EINVAL; |
b9170836 | 159 | |
4d5dcc42 | 160 | cs_tuners->down_threshold = input; |
b9170836 DJ |
161 | return count; |
162 | } | |
163 | ||
6c4640c3 VK |
164 | static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data, |
165 | const char *buf, size_t count) | |
b9170836 | 166 | { |
4471a34f | 167 | unsigned int input, j; |
b9170836 DJ |
168 | int ret; |
169 | ||
18a7247d DJ |
170 | ret = sscanf(buf, "%u", &input); |
171 | if (ret != 1) | |
b9170836 DJ |
172 | return -EINVAL; |
173 | ||
18a7247d | 174 | if (input > 1) |
b9170836 | 175 | input = 1; |
18a7247d | 176 | |
ff4b1789 | 177 | if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
b9170836 | 178 | return count; |
326c86de | 179 | |
ff4b1789 | 180 | dbs_data->ignore_nice_load = input; |
b9170836 | 181 | |
8e677ce8 | 182 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 183 | for_each_online_cpu(j) { |
4471a34f | 184 | struct cs_cpu_dbs_info_s *dbs_info; |
245b2e70 | 185 | dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
4471a34f | 186 | dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j, |
9366d840 | 187 | &dbs_info->cdbs.prev_cpu_wall, 0); |
ff4b1789 | 188 | if (dbs_data->ignore_nice_load) |
4471a34f VK |
189 | dbs_info->cdbs.prev_cpu_nice = |
190 | kcpustat_cpu(j).cpustat[CPUTIME_NICE]; | |
b9170836 | 191 | } |
b9170836 DJ |
192 | return count; |
193 | } | |
194 | ||
4d5dcc42 VK |
195 | static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf, |
196 | size_t count) | |
b9170836 | 197 | { |
4d5dcc42 | 198 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
199 | unsigned int input; |
200 | int ret; | |
18a7247d | 201 | ret = sscanf(buf, "%u", &input); |
b9170836 | 202 | |
18a7247d | 203 | if (ret != 1) |
b9170836 DJ |
204 | return -EINVAL; |
205 | ||
18a7247d | 206 | if (input > 100) |
b9170836 | 207 | input = 100; |
18a7247d | 208 | |
4471a34f VK |
209 | /* |
210 | * no need to test here if freq_step is zero as the user might actually | |
211 | * want this, they would be crazy though :) | |
212 | */ | |
4d5dcc42 | 213 | cs_tuners->freq_step = input; |
b9170836 DJ |
214 | return count; |
215 | } | |
216 | ||
c4435630 VK |
217 | gov_show_one_common(sampling_rate); |
218 | gov_show_one_common(sampling_down_factor); | |
219 | gov_show_one_common(up_threshold); | |
220 | gov_show_one_common(ignore_nice_load); | |
221 | gov_show_one_common(min_sampling_rate); | |
222 | gov_show_one(cs, down_threshold); | |
223 | gov_show_one(cs, freq_step); | |
224 | ||
225 | gov_attr_rw(sampling_rate); | |
226 | gov_attr_rw(sampling_down_factor); | |
227 | gov_attr_rw(up_threshold); | |
228 | gov_attr_rw(ignore_nice_load); | |
229 | gov_attr_ro(min_sampling_rate); | |
230 | gov_attr_rw(down_threshold); | |
231 | gov_attr_rw(freq_step); | |
232 | ||
233 | static struct attribute *cs_attributes[] = { | |
234 | &min_sampling_rate.attr, | |
235 | &sampling_rate.attr, | |
236 | &sampling_down_factor.attr, | |
237 | &up_threshold.attr, | |
238 | &down_threshold.attr, | |
239 | &ignore_nice_load.attr, | |
240 | &freq_step.attr, | |
b9170836 DJ |
241 | NULL |
242 | }; | |
243 | ||
b9170836 DJ |
244 | /************************** sysfs end ************************/ |
245 | ||
8e0484d2 | 246 | static int cs_init(struct dbs_data *dbs_data, bool notify) |
4d5dcc42 VK |
247 | { |
248 | struct cs_dbs_tuners *tuners; | |
249 | ||
d5b73cd8 | 250 | tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
4d5dcc42 VK |
251 | if (!tuners) { |
252 | pr_err("%s: kzalloc failed\n", __func__); | |
253 | return -ENOMEM; | |
254 | } | |
255 | ||
4d5dcc42 | 256 | tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
98765847 | 257 | tuners->freq_step = DEF_FREQUENCY_STEP; |
ff4b1789 VK |
258 | dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
259 | dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; | |
260 | dbs_data->ignore_nice_load = 0; | |
4d5dcc42 VK |
261 | |
262 | dbs_data->tuners = tuners; | |
263 | dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * | |
264 | jiffies_to_usecs(10); | |
8e0484d2 VK |
265 | |
266 | if (notify) | |
267 | cpufreq_register_notifier(&cs_cpufreq_notifier_block, | |
268 | CPUFREQ_TRANSITION_NOTIFIER); | |
269 | ||
4d5dcc42 VK |
270 | return 0; |
271 | } | |
272 | ||
8e0484d2 | 273 | static void cs_exit(struct dbs_data *dbs_data, bool notify) |
4d5dcc42 | 274 | { |
8e0484d2 VK |
275 | if (notify) |
276 | cpufreq_unregister_notifier(&cs_cpufreq_notifier_block, | |
277 | CPUFREQ_TRANSITION_NOTIFIER); | |
278 | ||
4d5dcc42 VK |
279 | kfree(dbs_data->tuners); |
280 | } | |
281 | ||
702c9e54 RW |
282 | static void cs_start(struct cpufreq_policy *policy) |
283 | { | |
284 | struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, policy->cpu); | |
285 | ||
286 | dbs_info->down_skip = 0; | |
287 | dbs_info->requested_freq = policy->cur; | |
288 | } | |
289 | ||
4471a34f | 290 | define_get_cpu_dbs_routines(cs_cpu_dbs_info); |
8e677ce8 | 291 | |
7bdad34d | 292 | static struct dbs_governor cs_dbs_gov = { |
af926185 RW |
293 | .gov = { |
294 | .name = "conservative", | |
906a6e5a | 295 | .governor = cpufreq_governor_dbs, |
af926185 RW |
296 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, |
297 | .owner = THIS_MODULE, | |
298 | }, | |
c4435630 | 299 | .kobj_type = { .default_attrs = cs_attributes }, |
4471a34f | 300 | .get_cpu_cdbs = get_cpu_cdbs, |
4471a34f | 301 | .gov_dbs_timer = cs_dbs_timer, |
4d5dcc42 VK |
302 | .init = cs_init, |
303 | .exit = cs_exit, | |
702c9e54 | 304 | .start = cs_start, |
4471a34f | 305 | }; |
b9170836 | 306 | |
7bdad34d | 307 | #define CPU_FREQ_GOV_CONSERVATIVE (&cs_dbs_gov.gov) |
af926185 | 308 | |
af926185 RW |
309 | static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
310 | void *data) | |
311 | { | |
312 | struct cpufreq_freqs *freq = data; | |
313 | struct cs_cpu_dbs_info_s *dbs_info = | |
314 | &per_cpu(cs_cpu_dbs_info, freq->cpu); | |
315 | struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu); | |
316 | ||
317 | if (!policy) | |
318 | return 0; | |
319 | ||
320 | /* policy isn't governed by conservative governor */ | |
321 | if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE) | |
322 | return 0; | |
323 | ||
324 | /* | |
325 | * we only care if our internally tracked freq moves outside the 'valid' | |
326 | * ranges of frequency available to us otherwise we do not change it | |
327 | */ | |
328 | if (dbs_info->requested_freq > policy->max | |
329 | || dbs_info->requested_freq < policy->min) | |
330 | dbs_info->requested_freq = freq->new; | |
331 | ||
332 | return 0; | |
333 | } | |
334 | ||
b9170836 DJ |
335 | static int __init cpufreq_gov_dbs_init(void) |
336 | { | |
af926185 | 337 | return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
338 | } |
339 | ||
340 | static void __exit cpufreq_gov_dbs_exit(void) | |
341 | { | |
af926185 | 342 | cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
343 | } |
344 | ||
11a80a9c | 345 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 346 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
347 | "Low Latency Frequency Transition capable processors " |
348 | "optimised for use in a battery environment"); | |
9acef487 | 349 | MODULE_LICENSE("GPL"); |
b9170836 | 350 | |
6915719b | 351 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
de1df26b RW |
352 | struct cpufreq_governor *cpufreq_default_governor(void) |
353 | { | |
af926185 | 354 | return CPU_FREQ_GOV_CONSERVATIVE; |
de1df26b RW |
355 | } |
356 | ||
6915719b JW |
357 | fs_initcall(cpufreq_gov_dbs_init); |
358 | #else | |
b9170836 | 359 | module_init(cpufreq_gov_dbs_init); |
6915719b | 360 | #endif |
b9170836 | 361 | module_exit(cpufreq_gov_dbs_exit); |