Commit | Line | Data |
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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 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
b9170836 | 16 | #include <linux/init.h> |
b9170836 | 17 | #include <linux/cpufreq.h> |
138a0128 | 18 | #include <linux/cpu.h> |
b9170836 DJ |
19 | #include <linux/jiffies.h> |
20 | #include <linux/kernel_stat.h> | |
3fc54d37 | 21 | #include <linux/mutex.h> |
8e677ce8 AC |
22 | #include <linux/hrtimer.h> |
23 | #include <linux/tick.h> | |
24 | #include <linux/ktime.h> | |
25 | #include <linux/sched.h> | |
26 | ||
b9170836 DJ |
27 | /* |
28 | * dbs is used in this file as a shortform for demandbased switching | |
29 | * It helps to keep variable names smaller, simpler | |
30 | */ | |
31 | ||
32 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
b9170836 | 33 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
b9170836 | 34 | |
18a7247d DJ |
35 | /* |
36 | * The polling frequency of this governor depends on the capability of | |
b9170836 | 37 | * the processor. Default polling frequency is 1000 times the transition |
18a7247d DJ |
38 | * latency of the processor. The governor will work on any processor with |
39 | * transition latency <= 10mS, using appropriate sampling | |
b9170836 | 40 | * rate. |
8e677ce8 AC |
41 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) |
42 | * this governor will not work. | |
b9170836 DJ |
43 | * All times here are in uS. |
44 | */ | |
2c906b31 | 45 | #define MIN_SAMPLING_RATE_RATIO (2) |
112124ab | 46 | |
cef9615a TR |
47 | static unsigned int min_sampling_rate; |
48 | ||
112124ab | 49 | #define LATENCY_MULTIPLIER (1000) |
cef9615a | 50 | #define MIN_LATENCY_MULTIPLIER (100) |
2c906b31 AC |
51 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
52 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
1c256245 | 53 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
b9170836 | 54 | |
c4028958 | 55 | static void do_dbs_timer(struct work_struct *work); |
b9170836 DJ |
56 | |
57 | struct cpu_dbs_info_s { | |
8e677ce8 AC |
58 | cputime64_t prev_cpu_idle; |
59 | cputime64_t prev_cpu_wall; | |
60 | cputime64_t prev_cpu_nice; | |
18a7247d | 61 | struct cpufreq_policy *cur_policy; |
8e677ce8 | 62 | struct delayed_work work; |
18a7247d DJ |
63 | unsigned int down_skip; |
64 | unsigned int requested_freq; | |
8e677ce8 AC |
65 | int cpu; |
66 | unsigned int enable:1; | |
ee88415c | 67 | /* |
68 | * percpu mutex that serializes governor limit change with | |
69 | * do_dbs_timer invocation. We do not want do_dbs_timer to run | |
70 | * when user is changing the governor or limits. | |
71 | */ | |
72 | struct mutex timer_mutex; | |
b9170836 | 73 | }; |
245b2e70 | 74 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cs_cpu_dbs_info); |
b9170836 DJ |
75 | |
76 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
77 | ||
4ec223d0 | 78 | /* |
326c86de | 79 | * dbs_mutex protects dbs_enable in governor start/stop. |
4ec223d0 | 80 | */ |
9acef487 | 81 | static DEFINE_MUTEX(dbs_mutex); |
b9170836 | 82 | |
8e677ce8 | 83 | static struct dbs_tuners { |
18a7247d DJ |
84 | unsigned int sampling_rate; |
85 | unsigned int sampling_down_factor; | |
86 | unsigned int up_threshold; | |
87 | unsigned int down_threshold; | |
88 | unsigned int ignore_nice; | |
89 | unsigned int freq_step; | |
8e677ce8 | 90 | } dbs_tuners_ins = { |
18a7247d DJ |
91 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
92 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
93 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
94 | .ignore_nice = 0, | |
95 | .freq_step = 5, | |
b9170836 DJ |
96 | }; |
97 | ||
a8d7c3bc EO |
98 | /* keep track of frequency transitions */ |
99 | static int | |
100 | dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, | |
101 | void *data) | |
102 | { | |
103 | struct cpufreq_freqs *freq = data; | |
245b2e70 | 104 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cs_cpu_dbs_info, |
a8d7c3bc EO |
105 | freq->cpu); |
106 | ||
f407a08b AC |
107 | struct cpufreq_policy *policy; |
108 | ||
a8d7c3bc EO |
109 | if (!this_dbs_info->enable) |
110 | return 0; | |
111 | ||
f407a08b AC |
112 | policy = this_dbs_info->cur_policy; |
113 | ||
114 | /* | |
115 | * we only care if our internally tracked freq moves outside | |
116 | * the 'valid' ranges of freqency available to us otherwise | |
117 | * we do not change it | |
118 | */ | |
119 | if (this_dbs_info->requested_freq > policy->max | |
120 | || this_dbs_info->requested_freq < policy->min) | |
121 | this_dbs_info->requested_freq = freq->new; | |
a8d7c3bc EO |
122 | |
123 | return 0; | |
124 | } | |
125 | ||
126 | static struct notifier_block dbs_cpufreq_notifier_block = { | |
127 | .notifier_call = dbs_cpufreq_notifier | |
128 | }; | |
129 | ||
b9170836 | 130 | /************************** sysfs interface ************************/ |
49b015ce TR |
131 | static ssize_t show_sampling_rate_min(struct kobject *kobj, |
132 | struct attribute *attr, char *buf) | |
b9170836 | 133 | { |
cef9615a | 134 | return sprintf(buf, "%u\n", min_sampling_rate); |
b9170836 DJ |
135 | } |
136 | ||
6dad2a29 | 137 | define_one_global_ro(sampling_rate_min); |
b9170836 DJ |
138 | |
139 | /* cpufreq_conservative Governor Tunables */ | |
140 | #define show_one(file_name, object) \ | |
141 | static ssize_t show_##file_name \ | |
49b015ce | 142 | (struct kobject *kobj, struct attribute *attr, char *buf) \ |
b9170836 DJ |
143 | { \ |
144 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
145 | } | |
146 | show_one(sampling_rate, sampling_rate); | |
147 | show_one(sampling_down_factor, sampling_down_factor); | |
148 | show_one(up_threshold, up_threshold); | |
149 | show_one(down_threshold, down_threshold); | |
001893cd | 150 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
151 | show_one(freq_step, freq_step); |
152 | ||
49b015ce TR |
153 | static ssize_t store_sampling_down_factor(struct kobject *a, |
154 | struct attribute *b, | |
155 | const char *buf, size_t count) | |
b9170836 DJ |
156 | { |
157 | unsigned int input; | |
158 | int ret; | |
9acef487 | 159 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 160 | |
2c906b31 | 161 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
162 | return -EINVAL; |
163 | ||
b9170836 | 164 | dbs_tuners_ins.sampling_down_factor = input; |
b9170836 DJ |
165 | return count; |
166 | } | |
167 | ||
49b015ce TR |
168 | static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, |
169 | const char *buf, size_t count) | |
b9170836 DJ |
170 | { |
171 | unsigned int input; | |
172 | int ret; | |
9acef487 | 173 | ret = sscanf(buf, "%u", &input); |
b9170836 | 174 | |
8e677ce8 | 175 | if (ret != 1) |
b9170836 | 176 | return -EINVAL; |
8e677ce8 | 177 | |
cef9615a | 178 | dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate); |
b9170836 DJ |
179 | return count; |
180 | } | |
181 | ||
49b015ce TR |
182 | static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, |
183 | const char *buf, size_t count) | |
b9170836 DJ |
184 | { |
185 | unsigned int input; | |
186 | int ret; | |
9acef487 | 187 | ret = sscanf(buf, "%u", &input); |
b9170836 | 188 | |
9acef487 | 189 | if (ret != 1 || input > 100 || |
326c86de | 190 | input <= dbs_tuners_ins.down_threshold) |
b9170836 | 191 | return -EINVAL; |
b9170836 DJ |
192 | |
193 | dbs_tuners_ins.up_threshold = input; | |
b9170836 DJ |
194 | return count; |
195 | } | |
196 | ||
49b015ce TR |
197 | static ssize_t store_down_threshold(struct kobject *a, struct attribute *b, |
198 | const char *buf, size_t count) | |
b9170836 DJ |
199 | { |
200 | unsigned int input; | |
201 | int ret; | |
9acef487 | 202 | ret = sscanf(buf, "%u", &input); |
b9170836 | 203 | |
8e677ce8 AC |
204 | /* cannot be lower than 11 otherwise freq will not fall */ |
205 | if (ret != 1 || input < 11 || input > 100 || | |
326c86de | 206 | input >= dbs_tuners_ins.up_threshold) |
b9170836 | 207 | return -EINVAL; |
b9170836 DJ |
208 | |
209 | dbs_tuners_ins.down_threshold = input; | |
b9170836 DJ |
210 | return count; |
211 | } | |
212 | ||
49b015ce TR |
213 | static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, |
214 | const char *buf, size_t count) | |
b9170836 DJ |
215 | { |
216 | unsigned int input; | |
217 | int ret; | |
218 | ||
219 | unsigned int j; | |
18a7247d DJ |
220 | |
221 | ret = sscanf(buf, "%u", &input); | |
222 | if (ret != 1) | |
b9170836 DJ |
223 | return -EINVAL; |
224 | ||
18a7247d | 225 | if (input > 1) |
b9170836 | 226 | input = 1; |
18a7247d | 227 | |
326c86de | 228 | if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */ |
b9170836 | 229 | return count; |
326c86de | 230 | |
b9170836 DJ |
231 | dbs_tuners_ins.ignore_nice = input; |
232 | ||
8e677ce8 | 233 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 234 | for_each_online_cpu(j) { |
8e677ce8 | 235 | struct cpu_dbs_info_s *dbs_info; |
245b2e70 | 236 | dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
237 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
238 | &dbs_info->prev_cpu_wall); | |
239 | if (dbs_tuners_ins.ignore_nice) | |
3292beb3 | 240 | dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
b9170836 | 241 | } |
b9170836 DJ |
242 | return count; |
243 | } | |
244 | ||
49b015ce TR |
245 | static ssize_t store_freq_step(struct kobject *a, struct attribute *b, |
246 | const char *buf, size_t count) | |
b9170836 DJ |
247 | { |
248 | unsigned int input; | |
249 | int ret; | |
18a7247d | 250 | ret = sscanf(buf, "%u", &input); |
b9170836 | 251 | |
18a7247d | 252 | if (ret != 1) |
b9170836 DJ |
253 | return -EINVAL; |
254 | ||
18a7247d | 255 | if (input > 100) |
b9170836 | 256 | input = 100; |
18a7247d | 257 | |
b9170836 DJ |
258 | /* no need to test here if freq_step is zero as the user might actually |
259 | * want this, they would be crazy though :) */ | |
b9170836 | 260 | dbs_tuners_ins.freq_step = input; |
b9170836 DJ |
261 | return count; |
262 | } | |
263 | ||
6dad2a29 BP |
264 | define_one_global_rw(sampling_rate); |
265 | define_one_global_rw(sampling_down_factor); | |
266 | define_one_global_rw(up_threshold); | |
267 | define_one_global_rw(down_threshold); | |
268 | define_one_global_rw(ignore_nice_load); | |
269 | define_one_global_rw(freq_step); | |
b9170836 | 270 | |
9acef487 | 271 | static struct attribute *dbs_attributes[] = { |
b9170836 DJ |
272 | &sampling_rate_min.attr, |
273 | &sampling_rate.attr, | |
274 | &sampling_down_factor.attr, | |
275 | &up_threshold.attr, | |
276 | &down_threshold.attr, | |
001893cd | 277 | &ignore_nice_load.attr, |
b9170836 DJ |
278 | &freq_step.attr, |
279 | NULL | |
280 | }; | |
281 | ||
282 | static struct attribute_group dbs_attr_group = { | |
283 | .attrs = dbs_attributes, | |
284 | .name = "conservative", | |
285 | }; | |
286 | ||
287 | /************************** sysfs end ************************/ | |
288 | ||
8e677ce8 | 289 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
b9170836 | 290 | { |
8e677ce8 | 291 | unsigned int load = 0; |
fd187aaf | 292 | unsigned int max_load = 0; |
f068c04b | 293 | unsigned int freq_target; |
b9170836 | 294 | |
8e677ce8 AC |
295 | struct cpufreq_policy *policy; |
296 | unsigned int j; | |
b9170836 | 297 | |
08a28e2e AC |
298 | policy = this_dbs_info->cur_policy; |
299 | ||
18a7247d | 300 | /* |
8e677ce8 AC |
301 | * Every sampling_rate, we check, if current idle time is less |
302 | * than 20% (default), then we try to increase frequency | |
303 | * Every sampling_rate*sampling_down_factor, we check, if current | |
304 | * idle time is more than 80%, then we try to decrease frequency | |
b9170836 | 305 | * |
18a7247d DJ |
306 | * Any frequency increase takes it to the maximum frequency. |
307 | * Frequency reduction happens at minimum steps of | |
8e677ce8 | 308 | * 5% (default) of maximum frequency |
b9170836 DJ |
309 | */ |
310 | ||
8e677ce8 AC |
311 | /* Get Absolute Load */ |
312 | for_each_cpu(j, policy->cpus) { | |
313 | struct cpu_dbs_info_s *j_dbs_info; | |
314 | cputime64_t cur_wall_time, cur_idle_time; | |
315 | unsigned int idle_time, wall_time; | |
b9170836 | 316 | |
245b2e70 | 317 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
318 | |
319 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
320 | ||
64861634 MS |
321 | wall_time = (unsigned int) |
322 | (cur_wall_time - j_dbs_info->prev_cpu_wall); | |
8e677ce8 | 323 | j_dbs_info->prev_cpu_wall = cur_wall_time; |
08a28e2e | 324 | |
64861634 MS |
325 | idle_time = (unsigned int) |
326 | (cur_idle_time - j_dbs_info->prev_cpu_idle); | |
8e677ce8 | 327 | j_dbs_info->prev_cpu_idle = cur_idle_time; |
b9170836 | 328 | |
8e677ce8 | 329 | if (dbs_tuners_ins.ignore_nice) { |
3292beb3 | 330 | u64 cur_nice; |
8e677ce8 AC |
331 | unsigned long cur_nice_jiffies; |
332 | ||
3292beb3 GC |
333 | cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - |
334 | j_dbs_info->prev_cpu_nice; | |
8e677ce8 AC |
335 | /* |
336 | * Assumption: nice time between sampling periods will | |
337 | * be less than 2^32 jiffies for 32 bit sys | |
338 | */ | |
339 | cur_nice_jiffies = (unsigned long) | |
340 | cputime64_to_jiffies64(cur_nice); | |
341 | ||
3292beb3 | 342 | j_dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
8e677ce8 AC |
343 | idle_time += jiffies_to_usecs(cur_nice_jiffies); |
344 | } | |
345 | ||
346 | if (unlikely(!wall_time || wall_time < idle_time)) | |
347 | continue; | |
348 | ||
349 | load = 100 * (wall_time - idle_time) / wall_time; | |
fd187aaf DB |
350 | |
351 | if (load > max_load) | |
352 | max_load = load; | |
8e677ce8 AC |
353 | } |
354 | ||
355 | /* | |
356 | * break out if we 'cannot' reduce the speed as the user might | |
357 | * want freq_step to be zero | |
358 | */ | |
359 | if (dbs_tuners_ins.freq_step == 0) | |
360 | return; | |
b9170836 | 361 | |
8e677ce8 | 362 | /* Check for frequency increase */ |
fd187aaf | 363 | if (max_load > dbs_tuners_ins.up_threshold) { |
a159b827 | 364 | this_dbs_info->down_skip = 0; |
790d76fa | 365 | |
b9170836 | 366 | /* if we are already at full speed then break out early */ |
a159b827 | 367 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 | 368 | return; |
18a7247d | 369 | |
f068c04b | 370 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 DJ |
371 | |
372 | /* max freq cannot be less than 100. But who knows.... */ | |
f068c04b DJ |
373 | if (unlikely(freq_target == 0)) |
374 | freq_target = 5; | |
18a7247d | 375 | |
f068c04b | 376 | this_dbs_info->requested_freq += freq_target; |
a159b827 AC |
377 | if (this_dbs_info->requested_freq > policy->max) |
378 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 379 | |
a159b827 | 380 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 381 | CPUFREQ_RELATION_H); |
b9170836 DJ |
382 | return; |
383 | } | |
384 | ||
8e677ce8 AC |
385 | /* |
386 | * The optimal frequency is the frequency that is the lowest that | |
387 | * can support the current CPU usage without triggering the up | |
388 | * policy. To be safe, we focus 10 points under the threshold. | |
389 | */ | |
fd187aaf | 390 | if (max_load < (dbs_tuners_ins.down_threshold - 10)) { |
f068c04b | 391 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 | 392 | |
f068c04b | 393 | this_dbs_info->requested_freq -= freq_target; |
a159b827 AC |
394 | if (this_dbs_info->requested_freq < policy->min) |
395 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 396 | |
8e677ce8 AC |
397 | /* |
398 | * if we cannot reduce the frequency anymore, break out early | |
399 | */ | |
400 | if (policy->cur == policy->min) | |
401 | return; | |
402 | ||
a159b827 | 403 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 404 | CPUFREQ_RELATION_H); |
b9170836 DJ |
405 | return; |
406 | } | |
407 | } | |
408 | ||
c4028958 | 409 | static void do_dbs_timer(struct work_struct *work) |
18a7247d | 410 | { |
8e677ce8 AC |
411 | struct cpu_dbs_info_s *dbs_info = |
412 | container_of(work, struct cpu_dbs_info_s, work.work); | |
413 | unsigned int cpu = dbs_info->cpu; | |
414 | ||
415 | /* We want all CPUs to do sampling nearly on same jiffy */ | |
416 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
417 | ||
418 | delay -= jiffies % delay; | |
419 | ||
ee88415c | 420 | mutex_lock(&dbs_info->timer_mutex); |
8e677ce8 AC |
421 | |
422 | dbs_check_cpu(dbs_info); | |
423 | ||
57df5573 | 424 | schedule_delayed_work_on(cpu, &dbs_info->work, delay); |
ee88415c | 425 | mutex_unlock(&dbs_info->timer_mutex); |
18a7247d | 426 | } |
b9170836 | 427 | |
8e677ce8 | 428 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 429 | { |
8e677ce8 AC |
430 | /* We want all CPUs to do sampling nearly on same jiffy */ |
431 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
432 | delay -= jiffies % delay; | |
433 | ||
434 | dbs_info->enable = 1; | |
203b42f7 | 435 | INIT_DEFERRABLE_WORK(&dbs_info->work, do_dbs_timer); |
57df5573 | 436 | schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay); |
b9170836 DJ |
437 | } |
438 | ||
8e677ce8 | 439 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 440 | { |
8e677ce8 | 441 | dbs_info->enable = 0; |
b253d2b2 | 442 | cancel_delayed_work_sync(&dbs_info->work); |
b9170836 DJ |
443 | } |
444 | ||
445 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
446 | unsigned int event) | |
447 | { | |
448 | unsigned int cpu = policy->cpu; | |
449 | struct cpu_dbs_info_s *this_dbs_info; | |
450 | unsigned int j; | |
914f7c31 | 451 | int rc; |
b9170836 | 452 | |
245b2e70 | 453 | this_dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); |
b9170836 DJ |
454 | |
455 | switch (event) { | |
456 | case CPUFREQ_GOV_START: | |
18a7247d | 457 | if ((!cpu_online(cpu)) || (!policy->cur)) |
b9170836 DJ |
458 | return -EINVAL; |
459 | ||
3fc54d37 | 460 | mutex_lock(&dbs_mutex); |
914f7c31 | 461 | |
835481d9 | 462 | for_each_cpu(j, policy->cpus) { |
b9170836 | 463 | struct cpu_dbs_info_s *j_dbs_info; |
245b2e70 | 464 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
b9170836 | 465 | j_dbs_info->cur_policy = policy; |
18a7247d | 466 | |
8e677ce8 AC |
467 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
468 | &j_dbs_info->prev_cpu_wall); | |
3292beb3 | 469 | if (dbs_tuners_ins.ignore_nice) |
8e677ce8 | 470 | j_dbs_info->prev_cpu_nice = |
3292beb3 | 471 | kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
b9170836 | 472 | } |
2d175069 | 473 | this_dbs_info->cpu = cpu; |
a159b827 AC |
474 | this_dbs_info->down_skip = 0; |
475 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 476 | |
ee88415c | 477 | mutex_init(&this_dbs_info->timer_mutex); |
b9170836 DJ |
478 | dbs_enable++; |
479 | /* | |
480 | * Start the timerschedule work, when this governor | |
481 | * is used for first time | |
482 | */ | |
483 | if (dbs_enable == 1) { | |
484 | unsigned int latency; | |
485 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
486 | latency = policy->cpuinfo.transition_latency / 1000; |
487 | if (latency == 0) | |
488 | latency = 1; | |
b9170836 | 489 | |
49b015ce TR |
490 | rc = sysfs_create_group(cpufreq_global_kobject, |
491 | &dbs_attr_group); | |
492 | if (rc) { | |
493 | mutex_unlock(&dbs_mutex); | |
494 | return rc; | |
495 | } | |
496 | ||
cef9615a TR |
497 | /* |
498 | * conservative does not implement micro like ondemand | |
499 | * governor, thus we are bound to jiffes/HZ | |
500 | */ | |
501 | min_sampling_rate = | |
502 | MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); | |
503 | /* Bring kernel and HW constraints together */ | |
504 | min_sampling_rate = max(min_sampling_rate, | |
505 | MIN_LATENCY_MULTIPLIER * latency); | |
506 | dbs_tuners_ins.sampling_rate = | |
507 | max(min_sampling_rate, | |
508 | latency * LATENCY_MULTIPLIER); | |
b9170836 | 509 | |
a8d7c3bc EO |
510 | cpufreq_register_notifier( |
511 | &dbs_cpufreq_notifier_block, | |
512 | CPUFREQ_TRANSITION_NOTIFIER); | |
b9170836 | 513 | } |
3fc54d37 | 514 | mutex_unlock(&dbs_mutex); |
8e677ce8 | 515 | |
7d26e2d5 | 516 | dbs_timer_init(this_dbs_info); |
517 | ||
b9170836 DJ |
518 | break; |
519 | ||
520 | case CPUFREQ_GOV_STOP: | |
8e677ce8 | 521 | dbs_timer_exit(this_dbs_info); |
7d26e2d5 | 522 | |
523 | mutex_lock(&dbs_mutex); | |
b9170836 | 524 | dbs_enable--; |
ee88415c | 525 | mutex_destroy(&this_dbs_info->timer_mutex); |
8e677ce8 | 526 | |
b9170836 DJ |
527 | /* |
528 | * Stop the timerschedule work, when this governor | |
529 | * is used for first time | |
530 | */ | |
8e677ce8 | 531 | if (dbs_enable == 0) |
a8d7c3bc EO |
532 | cpufreq_unregister_notifier( |
533 | &dbs_cpufreq_notifier_block, | |
534 | CPUFREQ_TRANSITION_NOTIFIER); | |
a8d7c3bc | 535 | |
3fc54d37 | 536 | mutex_unlock(&dbs_mutex); |
49b015ce TR |
537 | if (!dbs_enable) |
538 | sysfs_remove_group(cpufreq_global_kobject, | |
539 | &dbs_attr_group); | |
b9170836 DJ |
540 | |
541 | break; | |
542 | ||
543 | case CPUFREQ_GOV_LIMITS: | |
ee88415c | 544 | mutex_lock(&this_dbs_info->timer_mutex); |
b9170836 DJ |
545 | if (policy->max < this_dbs_info->cur_policy->cur) |
546 | __cpufreq_driver_target( | |
547 | this_dbs_info->cur_policy, | |
18a7247d | 548 | policy->max, CPUFREQ_RELATION_H); |
b9170836 DJ |
549 | else if (policy->min > this_dbs_info->cur_policy->cur) |
550 | __cpufreq_driver_target( | |
551 | this_dbs_info->cur_policy, | |
18a7247d | 552 | policy->min, CPUFREQ_RELATION_L); |
2d8fced7 | 553 | dbs_check_cpu(this_dbs_info); |
ee88415c | 554 | mutex_unlock(&this_dbs_info->timer_mutex); |
8e677ce8 | 555 | |
b9170836 DJ |
556 | break; |
557 | } | |
558 | return 0; | |
559 | } | |
560 | ||
c4d14bc0 SW |
561 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
562 | static | |
563 | #endif | |
1c256245 TR |
564 | struct cpufreq_governor cpufreq_gov_conservative = { |
565 | .name = "conservative", | |
566 | .governor = cpufreq_governor_dbs, | |
567 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
568 | .owner = THIS_MODULE, | |
b9170836 DJ |
569 | }; |
570 | ||
571 | static int __init cpufreq_gov_dbs_init(void) | |
572 | { | |
57df5573 | 573 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
574 | } |
575 | ||
576 | static void __exit cpufreq_gov_dbs_exit(void) | |
577 | { | |
1c256245 | 578 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
579 | } |
580 | ||
581 | ||
11a80a9c | 582 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 583 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
584 | "Low Latency Frequency Transition capable processors " |
585 | "optimised for use in a battery environment"); | |
9acef487 | 586 | MODULE_LICENSE("GPL"); |
b9170836 | 587 | |
6915719b JW |
588 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
589 | fs_initcall(cpufreq_gov_dbs_init); | |
590 | #else | |
b9170836 | 591 | module_init(cpufreq_gov_dbs_init); |
6915719b | 592 | #endif |
b9170836 | 593 | module_exit(cpufreq_gov_dbs_exit); |