Commit | Line | Data |
---|---|---|
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 | ||
8e677ce8 AC |
98 | static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, |
99 | cputime64_t *wall) | |
dac1c1a5 | 100 | { |
8e677ce8 AC |
101 | cputime64_t idle_time; |
102 | cputime64_t cur_wall_time; | |
103 | cputime64_t busy_time; | |
104 | ||
105 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); | |
106 | busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user, | |
107 | kstat_cpu(cpu).cpustat.system); | |
e08f5f5b | 108 | |
8e677ce8 AC |
109 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq); |
110 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq); | |
111 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal); | |
112 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice); | |
e08f5f5b | 113 | |
8e677ce8 AC |
114 | idle_time = cputime64_sub(cur_wall_time, busy_time); |
115 | if (wall) | |
54c9a35d | 116 | *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time); |
e08f5f5b | 117 | |
2feb690c | 118 | return (cputime64_t)jiffies_to_usecs(idle_time); |
8e677ce8 AC |
119 | } |
120 | ||
121 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) | |
122 | { | |
123 | u64 idle_time = get_cpu_idle_time_us(cpu, wall); | |
124 | ||
125 | if (idle_time == -1ULL) | |
126 | return get_cpu_idle_time_jiffy(cpu, wall); | |
127 | ||
128 | return idle_time; | |
dac1c1a5 DJ |
129 | } |
130 | ||
a8d7c3bc EO |
131 | /* keep track of frequency transitions */ |
132 | static int | |
133 | dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, | |
134 | void *data) | |
135 | { | |
136 | struct cpufreq_freqs *freq = data; | |
245b2e70 | 137 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cs_cpu_dbs_info, |
a8d7c3bc EO |
138 | freq->cpu); |
139 | ||
f407a08b AC |
140 | struct cpufreq_policy *policy; |
141 | ||
a8d7c3bc EO |
142 | if (!this_dbs_info->enable) |
143 | return 0; | |
144 | ||
f407a08b AC |
145 | policy = this_dbs_info->cur_policy; |
146 | ||
147 | /* | |
148 | * we only care if our internally tracked freq moves outside | |
149 | * the 'valid' ranges of freqency available to us otherwise | |
150 | * we do not change it | |
151 | */ | |
152 | if (this_dbs_info->requested_freq > policy->max | |
153 | || this_dbs_info->requested_freq < policy->min) | |
154 | this_dbs_info->requested_freq = freq->new; | |
a8d7c3bc EO |
155 | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static struct notifier_block dbs_cpufreq_notifier_block = { | |
160 | .notifier_call = dbs_cpufreq_notifier | |
161 | }; | |
162 | ||
b9170836 | 163 | /************************** sysfs interface ************************/ |
49b015ce TR |
164 | static ssize_t show_sampling_rate_min(struct kobject *kobj, |
165 | struct attribute *attr, char *buf) | |
b9170836 | 166 | { |
cef9615a | 167 | return sprintf(buf, "%u\n", min_sampling_rate); |
b9170836 DJ |
168 | } |
169 | ||
6dad2a29 | 170 | define_one_global_ro(sampling_rate_min); |
b9170836 DJ |
171 | |
172 | /* cpufreq_conservative Governor Tunables */ | |
173 | #define show_one(file_name, object) \ | |
174 | static ssize_t show_##file_name \ | |
49b015ce | 175 | (struct kobject *kobj, struct attribute *attr, char *buf) \ |
b9170836 DJ |
176 | { \ |
177 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
178 | } | |
179 | show_one(sampling_rate, sampling_rate); | |
180 | show_one(sampling_down_factor, sampling_down_factor); | |
181 | show_one(up_threshold, up_threshold); | |
182 | show_one(down_threshold, down_threshold); | |
001893cd | 183 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
184 | show_one(freq_step, freq_step); |
185 | ||
49b015ce TR |
186 | static ssize_t store_sampling_down_factor(struct kobject *a, |
187 | struct attribute *b, | |
188 | const char *buf, size_t count) | |
b9170836 DJ |
189 | { |
190 | unsigned int input; | |
191 | int ret; | |
9acef487 | 192 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 193 | |
2c906b31 | 194 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
195 | return -EINVAL; |
196 | ||
b9170836 | 197 | dbs_tuners_ins.sampling_down_factor = input; |
b9170836 DJ |
198 | return count; |
199 | } | |
200 | ||
49b015ce TR |
201 | static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, |
202 | const char *buf, size_t count) | |
b9170836 DJ |
203 | { |
204 | unsigned int input; | |
205 | int ret; | |
9acef487 | 206 | ret = sscanf(buf, "%u", &input); |
b9170836 | 207 | |
8e677ce8 | 208 | if (ret != 1) |
b9170836 | 209 | return -EINVAL; |
8e677ce8 | 210 | |
cef9615a | 211 | dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate); |
b9170836 DJ |
212 | return count; |
213 | } | |
214 | ||
49b015ce TR |
215 | static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, |
216 | const char *buf, size_t count) | |
b9170836 DJ |
217 | { |
218 | unsigned int input; | |
219 | int ret; | |
9acef487 | 220 | ret = sscanf(buf, "%u", &input); |
b9170836 | 221 | |
9acef487 | 222 | if (ret != 1 || input > 100 || |
326c86de | 223 | input <= dbs_tuners_ins.down_threshold) |
b9170836 | 224 | return -EINVAL; |
b9170836 DJ |
225 | |
226 | dbs_tuners_ins.up_threshold = input; | |
b9170836 DJ |
227 | return count; |
228 | } | |
229 | ||
49b015ce TR |
230 | static ssize_t store_down_threshold(struct kobject *a, struct attribute *b, |
231 | const char *buf, size_t count) | |
b9170836 DJ |
232 | { |
233 | unsigned int input; | |
234 | int ret; | |
9acef487 | 235 | ret = sscanf(buf, "%u", &input); |
b9170836 | 236 | |
8e677ce8 AC |
237 | /* cannot be lower than 11 otherwise freq will not fall */ |
238 | if (ret != 1 || input < 11 || input > 100 || | |
326c86de | 239 | input >= dbs_tuners_ins.up_threshold) |
b9170836 | 240 | return -EINVAL; |
b9170836 DJ |
241 | |
242 | dbs_tuners_ins.down_threshold = input; | |
b9170836 DJ |
243 | return count; |
244 | } | |
245 | ||
49b015ce TR |
246 | static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, |
247 | const char *buf, size_t count) | |
b9170836 DJ |
248 | { |
249 | unsigned int input; | |
250 | int ret; | |
251 | ||
252 | unsigned int j; | |
18a7247d DJ |
253 | |
254 | ret = sscanf(buf, "%u", &input); | |
255 | if (ret != 1) | |
b9170836 DJ |
256 | return -EINVAL; |
257 | ||
18a7247d | 258 | if (input > 1) |
b9170836 | 259 | input = 1; |
18a7247d | 260 | |
326c86de | 261 | if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */ |
b9170836 | 262 | return count; |
326c86de | 263 | |
b9170836 DJ |
264 | dbs_tuners_ins.ignore_nice = input; |
265 | ||
8e677ce8 | 266 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 267 | for_each_online_cpu(j) { |
8e677ce8 | 268 | struct cpu_dbs_info_s *dbs_info; |
245b2e70 | 269 | dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
270 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
271 | &dbs_info->prev_cpu_wall); | |
272 | if (dbs_tuners_ins.ignore_nice) | |
273 | dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
b9170836 | 274 | } |
b9170836 DJ |
275 | return count; |
276 | } | |
277 | ||
49b015ce TR |
278 | static ssize_t store_freq_step(struct kobject *a, struct attribute *b, |
279 | const char *buf, size_t count) | |
b9170836 DJ |
280 | { |
281 | unsigned int input; | |
282 | int ret; | |
18a7247d | 283 | ret = sscanf(buf, "%u", &input); |
b9170836 | 284 | |
18a7247d | 285 | if (ret != 1) |
b9170836 DJ |
286 | return -EINVAL; |
287 | ||
18a7247d | 288 | if (input > 100) |
b9170836 | 289 | input = 100; |
18a7247d | 290 | |
b9170836 DJ |
291 | /* no need to test here if freq_step is zero as the user might actually |
292 | * want this, they would be crazy though :) */ | |
b9170836 | 293 | dbs_tuners_ins.freq_step = input; |
b9170836 DJ |
294 | return count; |
295 | } | |
296 | ||
6dad2a29 BP |
297 | define_one_global_rw(sampling_rate); |
298 | define_one_global_rw(sampling_down_factor); | |
299 | define_one_global_rw(up_threshold); | |
300 | define_one_global_rw(down_threshold); | |
301 | define_one_global_rw(ignore_nice_load); | |
302 | define_one_global_rw(freq_step); | |
b9170836 | 303 | |
9acef487 | 304 | static struct attribute *dbs_attributes[] = { |
b9170836 DJ |
305 | &sampling_rate_min.attr, |
306 | &sampling_rate.attr, | |
307 | &sampling_down_factor.attr, | |
308 | &up_threshold.attr, | |
309 | &down_threshold.attr, | |
001893cd | 310 | &ignore_nice_load.attr, |
b9170836 DJ |
311 | &freq_step.attr, |
312 | NULL | |
313 | }; | |
314 | ||
315 | static struct attribute_group dbs_attr_group = { | |
316 | .attrs = dbs_attributes, | |
317 | .name = "conservative", | |
318 | }; | |
319 | ||
320 | /************************** sysfs end ************************/ | |
321 | ||
8e677ce8 | 322 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
b9170836 | 323 | { |
8e677ce8 | 324 | unsigned int load = 0; |
fd187aaf | 325 | unsigned int max_load = 0; |
f068c04b | 326 | unsigned int freq_target; |
b9170836 | 327 | |
8e677ce8 AC |
328 | struct cpufreq_policy *policy; |
329 | unsigned int j; | |
b9170836 | 330 | |
08a28e2e AC |
331 | policy = this_dbs_info->cur_policy; |
332 | ||
18a7247d | 333 | /* |
8e677ce8 AC |
334 | * Every sampling_rate, we check, if current idle time is less |
335 | * than 20% (default), then we try to increase frequency | |
336 | * Every sampling_rate*sampling_down_factor, we check, if current | |
337 | * idle time is more than 80%, then we try to decrease frequency | |
b9170836 | 338 | * |
18a7247d DJ |
339 | * Any frequency increase takes it to the maximum frequency. |
340 | * Frequency reduction happens at minimum steps of | |
8e677ce8 | 341 | * 5% (default) of maximum frequency |
b9170836 DJ |
342 | */ |
343 | ||
8e677ce8 AC |
344 | /* Get Absolute Load */ |
345 | for_each_cpu(j, policy->cpus) { | |
346 | struct cpu_dbs_info_s *j_dbs_info; | |
347 | cputime64_t cur_wall_time, cur_idle_time; | |
348 | unsigned int idle_time, wall_time; | |
b9170836 | 349 | |
245b2e70 | 350 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
351 | |
352 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
353 | ||
354 | wall_time = (unsigned int) cputime64_sub(cur_wall_time, | |
355 | j_dbs_info->prev_cpu_wall); | |
356 | j_dbs_info->prev_cpu_wall = cur_wall_time; | |
08a28e2e | 357 | |
8e677ce8 AC |
358 | idle_time = (unsigned int) cputime64_sub(cur_idle_time, |
359 | j_dbs_info->prev_cpu_idle); | |
360 | j_dbs_info->prev_cpu_idle = cur_idle_time; | |
b9170836 | 361 | |
8e677ce8 AC |
362 | if (dbs_tuners_ins.ignore_nice) { |
363 | cputime64_t cur_nice; | |
364 | unsigned long cur_nice_jiffies; | |
365 | ||
366 | cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice, | |
367 | j_dbs_info->prev_cpu_nice); | |
368 | /* | |
369 | * Assumption: nice time between sampling periods will | |
370 | * be less than 2^32 jiffies for 32 bit sys | |
371 | */ | |
372 | cur_nice_jiffies = (unsigned long) | |
373 | cputime64_to_jiffies64(cur_nice); | |
374 | ||
375 | j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
376 | idle_time += jiffies_to_usecs(cur_nice_jiffies); | |
377 | } | |
378 | ||
379 | if (unlikely(!wall_time || wall_time < idle_time)) | |
380 | continue; | |
381 | ||
382 | load = 100 * (wall_time - idle_time) / wall_time; | |
fd187aaf DB |
383 | |
384 | if (load > max_load) | |
385 | max_load = load; | |
8e677ce8 AC |
386 | } |
387 | ||
388 | /* | |
389 | * break out if we 'cannot' reduce the speed as the user might | |
390 | * want freq_step to be zero | |
391 | */ | |
392 | if (dbs_tuners_ins.freq_step == 0) | |
393 | return; | |
b9170836 | 394 | |
8e677ce8 | 395 | /* Check for frequency increase */ |
fd187aaf | 396 | if (max_load > dbs_tuners_ins.up_threshold) { |
a159b827 | 397 | this_dbs_info->down_skip = 0; |
790d76fa | 398 | |
b9170836 | 399 | /* if we are already at full speed then break out early */ |
a159b827 | 400 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 | 401 | return; |
18a7247d | 402 | |
f068c04b | 403 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 DJ |
404 | |
405 | /* max freq cannot be less than 100. But who knows.... */ | |
f068c04b DJ |
406 | if (unlikely(freq_target == 0)) |
407 | freq_target = 5; | |
18a7247d | 408 | |
f068c04b | 409 | this_dbs_info->requested_freq += freq_target; |
a159b827 AC |
410 | if (this_dbs_info->requested_freq > policy->max) |
411 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 412 | |
a159b827 | 413 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 414 | CPUFREQ_RELATION_H); |
b9170836 DJ |
415 | return; |
416 | } | |
417 | ||
8e677ce8 AC |
418 | /* |
419 | * The optimal frequency is the frequency that is the lowest that | |
420 | * can support the current CPU usage without triggering the up | |
421 | * policy. To be safe, we focus 10 points under the threshold. | |
422 | */ | |
fd187aaf | 423 | if (max_load < (dbs_tuners_ins.down_threshold - 10)) { |
f068c04b | 424 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 | 425 | |
f068c04b | 426 | this_dbs_info->requested_freq -= freq_target; |
a159b827 AC |
427 | if (this_dbs_info->requested_freq < policy->min) |
428 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 429 | |
8e677ce8 AC |
430 | /* |
431 | * if we cannot reduce the frequency anymore, break out early | |
432 | */ | |
433 | if (policy->cur == policy->min) | |
434 | return; | |
435 | ||
a159b827 | 436 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 437 | CPUFREQ_RELATION_H); |
b9170836 DJ |
438 | return; |
439 | } | |
440 | } | |
441 | ||
c4028958 | 442 | static void do_dbs_timer(struct work_struct *work) |
18a7247d | 443 | { |
8e677ce8 AC |
444 | struct cpu_dbs_info_s *dbs_info = |
445 | container_of(work, struct cpu_dbs_info_s, work.work); | |
446 | unsigned int cpu = dbs_info->cpu; | |
447 | ||
448 | /* We want all CPUs to do sampling nearly on same jiffy */ | |
449 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
450 | ||
451 | delay -= jiffies % delay; | |
452 | ||
ee88415c | 453 | mutex_lock(&dbs_info->timer_mutex); |
8e677ce8 AC |
454 | |
455 | dbs_check_cpu(dbs_info); | |
456 | ||
57df5573 | 457 | schedule_delayed_work_on(cpu, &dbs_info->work, delay); |
ee88415c | 458 | mutex_unlock(&dbs_info->timer_mutex); |
18a7247d | 459 | } |
b9170836 | 460 | |
8e677ce8 | 461 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 462 | { |
8e677ce8 AC |
463 | /* We want all CPUs to do sampling nearly on same jiffy */ |
464 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
465 | delay -= jiffies % delay; | |
466 | ||
467 | dbs_info->enable = 1; | |
468 | INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); | |
57df5573 | 469 | schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay); |
b9170836 DJ |
470 | } |
471 | ||
8e677ce8 | 472 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 473 | { |
8e677ce8 | 474 | dbs_info->enable = 0; |
b253d2b2 | 475 | cancel_delayed_work_sync(&dbs_info->work); |
b9170836 DJ |
476 | } |
477 | ||
478 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
479 | unsigned int event) | |
480 | { | |
481 | unsigned int cpu = policy->cpu; | |
482 | struct cpu_dbs_info_s *this_dbs_info; | |
483 | unsigned int j; | |
914f7c31 | 484 | int rc; |
b9170836 | 485 | |
245b2e70 | 486 | this_dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); |
b9170836 DJ |
487 | |
488 | switch (event) { | |
489 | case CPUFREQ_GOV_START: | |
18a7247d | 490 | if ((!cpu_online(cpu)) || (!policy->cur)) |
b9170836 DJ |
491 | return -EINVAL; |
492 | ||
3fc54d37 | 493 | mutex_lock(&dbs_mutex); |
914f7c31 | 494 | |
835481d9 | 495 | for_each_cpu(j, policy->cpus) { |
b9170836 | 496 | struct cpu_dbs_info_s *j_dbs_info; |
245b2e70 | 497 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
b9170836 | 498 | j_dbs_info->cur_policy = policy; |
18a7247d | 499 | |
8e677ce8 AC |
500 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
501 | &j_dbs_info->prev_cpu_wall); | |
502 | if (dbs_tuners_ins.ignore_nice) { | |
503 | j_dbs_info->prev_cpu_nice = | |
504 | kstat_cpu(j).cpustat.nice; | |
505 | } | |
b9170836 | 506 | } |
a159b827 AC |
507 | this_dbs_info->down_skip = 0; |
508 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 509 | |
ee88415c | 510 | mutex_init(&this_dbs_info->timer_mutex); |
b9170836 DJ |
511 | dbs_enable++; |
512 | /* | |
513 | * Start the timerschedule work, when this governor | |
514 | * is used for first time | |
515 | */ | |
516 | if (dbs_enable == 1) { | |
517 | unsigned int latency; | |
518 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
519 | latency = policy->cpuinfo.transition_latency / 1000; |
520 | if (latency == 0) | |
521 | latency = 1; | |
b9170836 | 522 | |
49b015ce TR |
523 | rc = sysfs_create_group(cpufreq_global_kobject, |
524 | &dbs_attr_group); | |
525 | if (rc) { | |
526 | mutex_unlock(&dbs_mutex); | |
527 | return rc; | |
528 | } | |
529 | ||
cef9615a TR |
530 | /* |
531 | * conservative does not implement micro like ondemand | |
532 | * governor, thus we are bound to jiffes/HZ | |
533 | */ | |
534 | min_sampling_rate = | |
535 | MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); | |
536 | /* Bring kernel and HW constraints together */ | |
537 | min_sampling_rate = max(min_sampling_rate, | |
538 | MIN_LATENCY_MULTIPLIER * latency); | |
539 | dbs_tuners_ins.sampling_rate = | |
540 | max(min_sampling_rate, | |
541 | latency * LATENCY_MULTIPLIER); | |
b9170836 | 542 | |
a8d7c3bc EO |
543 | cpufreq_register_notifier( |
544 | &dbs_cpufreq_notifier_block, | |
545 | CPUFREQ_TRANSITION_NOTIFIER); | |
b9170836 | 546 | } |
3fc54d37 | 547 | mutex_unlock(&dbs_mutex); |
8e677ce8 | 548 | |
7d26e2d5 | 549 | dbs_timer_init(this_dbs_info); |
550 | ||
b9170836 DJ |
551 | break; |
552 | ||
553 | case CPUFREQ_GOV_STOP: | |
8e677ce8 | 554 | dbs_timer_exit(this_dbs_info); |
7d26e2d5 | 555 | |
556 | mutex_lock(&dbs_mutex); | |
b9170836 | 557 | dbs_enable--; |
ee88415c | 558 | mutex_destroy(&this_dbs_info->timer_mutex); |
8e677ce8 | 559 | |
b9170836 DJ |
560 | /* |
561 | * Stop the timerschedule work, when this governor | |
562 | * is used for first time | |
563 | */ | |
8e677ce8 | 564 | if (dbs_enable == 0) |
a8d7c3bc EO |
565 | cpufreq_unregister_notifier( |
566 | &dbs_cpufreq_notifier_block, | |
567 | CPUFREQ_TRANSITION_NOTIFIER); | |
a8d7c3bc | 568 | |
3fc54d37 | 569 | mutex_unlock(&dbs_mutex); |
49b015ce TR |
570 | if (!dbs_enable) |
571 | sysfs_remove_group(cpufreq_global_kobject, | |
572 | &dbs_attr_group); | |
b9170836 DJ |
573 | |
574 | break; | |
575 | ||
576 | case CPUFREQ_GOV_LIMITS: | |
ee88415c | 577 | mutex_lock(&this_dbs_info->timer_mutex); |
b9170836 DJ |
578 | if (policy->max < this_dbs_info->cur_policy->cur) |
579 | __cpufreq_driver_target( | |
580 | this_dbs_info->cur_policy, | |
18a7247d | 581 | policy->max, CPUFREQ_RELATION_H); |
b9170836 DJ |
582 | else if (policy->min > this_dbs_info->cur_policy->cur) |
583 | __cpufreq_driver_target( | |
584 | this_dbs_info->cur_policy, | |
18a7247d | 585 | policy->min, CPUFREQ_RELATION_L); |
ee88415c | 586 | mutex_unlock(&this_dbs_info->timer_mutex); |
8e677ce8 | 587 | |
b9170836 DJ |
588 | break; |
589 | } | |
590 | return 0; | |
591 | } | |
592 | ||
c4d14bc0 SW |
593 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
594 | static | |
595 | #endif | |
1c256245 TR |
596 | struct cpufreq_governor cpufreq_gov_conservative = { |
597 | .name = "conservative", | |
598 | .governor = cpufreq_governor_dbs, | |
599 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
600 | .owner = THIS_MODULE, | |
b9170836 DJ |
601 | }; |
602 | ||
603 | static int __init cpufreq_gov_dbs_init(void) | |
604 | { | |
57df5573 | 605 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
606 | } |
607 | ||
608 | static void __exit cpufreq_gov_dbs_exit(void) | |
609 | { | |
1c256245 | 610 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
611 | } |
612 | ||
613 | ||
11a80a9c | 614 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 615 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
616 | "Low Latency Frequency Transition capable processors " |
617 | "optimised for use in a battery environment"); | |
9acef487 | 618 | MODULE_LICENSE("GPL"); |
b9170836 | 619 | |
6915719b JW |
620 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
621 | fs_initcall(cpufreq_gov_dbs_init); | |
622 | #else | |
b9170836 | 623 | module_init(cpufreq_gov_dbs_init); |
6915719b | 624 | #endif |
b9170836 | 625 | module_exit(cpufreq_gov_dbs_exit); |