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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> | |
7 | * (C) 2004 Alexander Clouter <alex-kernel@digriz.org.uk> | |
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> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/ctype.h> | |
20 | #include <linux/cpufreq.h> | |
21 | #include <linux/sysctl.h> | |
22 | #include <linux/types.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/sysfs.h> | |
25 | #include <linux/sched.h> | |
26 | #include <linux/kmod.h> | |
27 | #include <linux/workqueue.h> | |
28 | #include <linux/jiffies.h> | |
29 | #include <linux/kernel_stat.h> | |
30 | #include <linux/percpu.h> | |
3fc54d37 | 31 | #include <linux/mutex.h> |
b9170836 DJ |
32 | /* |
33 | * dbs is used in this file as a shortform for demandbased switching | |
34 | * It helps to keep variable names smaller, simpler | |
35 | */ | |
36 | ||
37 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
b9170836 | 38 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
b9170836 DJ |
39 | |
40 | /* | |
41 | * The polling frequency of this governor depends on the capability of | |
42 | * the processor. Default polling frequency is 1000 times the transition | |
43 | * latency of the processor. The governor will work on any processor with | |
44 | * transition latency <= 10mS, using appropriate sampling | |
45 | * rate. | |
46 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
47 | * this governor will not work. | |
48 | * All times here are in uS. | |
49 | */ | |
50 | static unsigned int def_sampling_rate; | |
2c906b31 AC |
51 | #define MIN_SAMPLING_RATE_RATIO (2) |
52 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
53 | #define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
54 | #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
b9170836 | 55 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
2c906b31 AC |
56 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
57 | #define DEF_SAMPLING_DOWN_FACTOR (1) | |
58 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 DJ |
59 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
60 | ||
61 | static void do_dbs_timer(void *data); | |
62 | ||
63 | struct cpu_dbs_info_s { | |
64 | struct cpufreq_policy *cur_policy; | |
65 | unsigned int prev_cpu_idle_up; | |
66 | unsigned int prev_cpu_idle_down; | |
67 | unsigned int enable; | |
68 | }; | |
69 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
70 | ||
71 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
72 | ||
3fc54d37 | 73 | static DEFINE_MUTEX (dbs_mutex); |
b9170836 DJ |
74 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
75 | ||
76 | struct dbs_tuners { | |
77 | unsigned int sampling_rate; | |
78 | unsigned int sampling_down_factor; | |
79 | unsigned int up_threshold; | |
80 | unsigned int down_threshold; | |
81 | unsigned int ignore_nice; | |
82 | unsigned int freq_step; | |
83 | }; | |
84 | ||
85 | static struct dbs_tuners dbs_tuners_ins = { | |
86 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
87 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
88 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
89 | }; | |
90 | ||
dac1c1a5 DJ |
91 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
92 | { | |
93 | return kstat_cpu(cpu).cpustat.idle + | |
94 | kstat_cpu(cpu).cpustat.iowait + | |
001893cd | 95 | ( dbs_tuners_ins.ignore_nice ? |
dac1c1a5 DJ |
96 | kstat_cpu(cpu).cpustat.nice : |
97 | 0); | |
98 | } | |
99 | ||
b9170836 DJ |
100 | /************************** sysfs interface ************************/ |
101 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
102 | { | |
103 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
104 | } | |
105 | ||
106 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
107 | { | |
108 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
109 | } | |
110 | ||
111 | #define define_one_ro(_name) \ | |
112 | static struct freq_attr _name = \ | |
113 | __ATTR(_name, 0444, show_##_name, NULL) | |
114 | ||
115 | define_one_ro(sampling_rate_max); | |
116 | define_one_ro(sampling_rate_min); | |
117 | ||
118 | /* cpufreq_conservative Governor Tunables */ | |
119 | #define show_one(file_name, object) \ | |
120 | static ssize_t show_##file_name \ | |
121 | (struct cpufreq_policy *unused, char *buf) \ | |
122 | { \ | |
123 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
124 | } | |
125 | show_one(sampling_rate, sampling_rate); | |
126 | show_one(sampling_down_factor, sampling_down_factor); | |
127 | show_one(up_threshold, up_threshold); | |
128 | show_one(down_threshold, down_threshold); | |
001893cd | 129 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
130 | show_one(freq_step, freq_step); |
131 | ||
132 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, | |
133 | const char *buf, size_t count) | |
134 | { | |
135 | unsigned int input; | |
136 | int ret; | |
137 | ret = sscanf (buf, "%u", &input); | |
2c906b31 | 138 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
139 | return -EINVAL; |
140 | ||
3fc54d37 | 141 | mutex_lock(&dbs_mutex); |
b9170836 | 142 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 143 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
144 | |
145 | return count; | |
146 | } | |
147 | ||
148 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
149 | const char *buf, size_t count) | |
150 | { | |
151 | unsigned int input; | |
152 | int ret; | |
153 | ret = sscanf (buf, "%u", &input); | |
154 | ||
3fc54d37 | 155 | mutex_lock(&dbs_mutex); |
b9170836 | 156 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 157 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
158 | return -EINVAL; |
159 | } | |
160 | ||
161 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 162 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
163 | |
164 | return count; | |
165 | } | |
166 | ||
167 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, | |
168 | const char *buf, size_t count) | |
169 | { | |
170 | unsigned int input; | |
171 | int ret; | |
172 | ret = sscanf (buf, "%u", &input); | |
173 | ||
3fc54d37 | 174 | mutex_lock(&dbs_mutex); |
2c906b31 | 175 | if (ret != 1 || input > 100 || input < 0 || |
b9170836 | 176 | input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 177 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
178 | return -EINVAL; |
179 | } | |
180 | ||
181 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 182 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
183 | |
184 | return count; | |
185 | } | |
186 | ||
187 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
188 | const char *buf, size_t count) | |
189 | { | |
190 | unsigned int input; | |
191 | int ret; | |
192 | ret = sscanf (buf, "%u", &input); | |
193 | ||
3fc54d37 | 194 | mutex_lock(&dbs_mutex); |
2c906b31 | 195 | if (ret != 1 || input > 100 || input < 0 || |
b9170836 | 196 | input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 197 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
198 | return -EINVAL; |
199 | } | |
200 | ||
201 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 202 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
203 | |
204 | return count; | |
205 | } | |
206 | ||
001893cd | 207 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
208 | const char *buf, size_t count) |
209 | { | |
210 | unsigned int input; | |
211 | int ret; | |
212 | ||
213 | unsigned int j; | |
214 | ||
215 | ret = sscanf (buf, "%u", &input); | |
216 | if ( ret != 1 ) | |
217 | return -EINVAL; | |
218 | ||
219 | if ( input > 1 ) | |
220 | input = 1; | |
221 | ||
3fc54d37 | 222 | mutex_lock(&dbs_mutex); |
b9170836 | 223 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 224 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
225 | return count; |
226 | } | |
227 | dbs_tuners_ins.ignore_nice = input; | |
228 | ||
229 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 230 | for_each_online_cpu(j) { |
b9170836 DJ |
231 | struct cpu_dbs_info_s *j_dbs_info; |
232 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 233 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
234 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
235 | } | |
3fc54d37 | 236 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
237 | |
238 | return count; | |
239 | } | |
240 | ||
241 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
242 | const char *buf, size_t count) | |
243 | { | |
244 | unsigned int input; | |
245 | int ret; | |
246 | ||
247 | ret = sscanf (buf, "%u", &input); | |
248 | ||
249 | if ( ret != 1 ) | |
250 | return -EINVAL; | |
251 | ||
252 | if ( input > 100 ) | |
253 | input = 100; | |
254 | ||
255 | /* no need to test here if freq_step is zero as the user might actually | |
256 | * want this, they would be crazy though :) */ | |
3fc54d37 | 257 | mutex_lock(&dbs_mutex); |
b9170836 | 258 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 259 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
260 | |
261 | return count; | |
262 | } | |
263 | ||
264 | #define define_one_rw(_name) \ | |
265 | static struct freq_attr _name = \ | |
266 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
267 | ||
268 | define_one_rw(sampling_rate); | |
269 | define_one_rw(sampling_down_factor); | |
270 | define_one_rw(up_threshold); | |
271 | define_one_rw(down_threshold); | |
001893cd | 272 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
273 | define_one_rw(freq_step); |
274 | ||
275 | static struct attribute * dbs_attributes[] = { | |
276 | &sampling_rate_max.attr, | |
277 | &sampling_rate_min.attr, | |
278 | &sampling_rate.attr, | |
279 | &sampling_down_factor.attr, | |
280 | &up_threshold.attr, | |
281 | &down_threshold.attr, | |
001893cd | 282 | &ignore_nice_load.attr, |
b9170836 DJ |
283 | &freq_step.attr, |
284 | NULL | |
285 | }; | |
286 | ||
287 | static struct attribute_group dbs_attr_group = { | |
288 | .attrs = dbs_attributes, | |
289 | .name = "conservative", | |
290 | }; | |
291 | ||
292 | /************************** sysfs end ************************/ | |
293 | ||
294 | static void dbs_check_cpu(int cpu) | |
295 | { | |
296 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
b9170836 DJ |
297 | unsigned int freq_step; |
298 | unsigned int freq_down_sampling_rate; | |
299 | static int down_skip[NR_CPUS]; | |
300 | static int requested_freq[NR_CPUS]; | |
301 | static unsigned short init_flag = 0; | |
302 | struct cpu_dbs_info_s *this_dbs_info; | |
303 | struct cpu_dbs_info_s *dbs_info; | |
304 | ||
305 | struct cpufreq_policy *policy; | |
306 | unsigned int j; | |
307 | ||
308 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
309 | if (!this_dbs_info->enable) | |
310 | return; | |
311 | ||
312 | policy = this_dbs_info->cur_policy; | |
313 | ||
314 | if ( init_flag == 0 ) { | |
92732144 DJ |
315 | for_each_online_cpu(j) { |
316 | dbs_info = &per_cpu(cpu_dbs_info, j); | |
317 | requested_freq[j] = dbs_info->cur_policy->cur; | |
b9170836 DJ |
318 | } |
319 | init_flag = 1; | |
320 | } | |
321 | ||
322 | /* | |
323 | * The default safe range is 20% to 80% | |
324 | * Every sampling_rate, we check | |
325 | * - If current idle time is less than 20%, then we try to | |
326 | * increase frequency | |
327 | * Every sampling_rate*sampling_down_factor, we check | |
328 | * - If current idle time is more than 80%, then we try to | |
329 | * decrease frequency | |
330 | * | |
331 | * Any frequency increase takes it to the maximum frequency. | |
332 | * Frequency reduction happens at minimum steps of | |
333 | * 5% (default) of max_frequency | |
334 | */ | |
335 | ||
336 | /* Check for frequency increase */ | |
9c7d269b | 337 | idle_ticks = UINT_MAX; |
b9170836 | 338 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 339 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
340 | struct cpu_dbs_info_s *j_dbs_info; |
341 | ||
b9170836 DJ |
342 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
343 | /* Check for frequency increase */ | |
dac1c1a5 | 344 | total_idle_ticks = get_cpu_idle_time(j); |
b9170836 DJ |
345 | tmp_idle_ticks = total_idle_ticks - |
346 | j_dbs_info->prev_cpu_idle_up; | |
347 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
348 | ||
349 | if (tmp_idle_ticks < idle_ticks) | |
350 | idle_ticks = tmp_idle_ticks; | |
351 | } | |
352 | ||
353 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
354 | idle_ticks *= 100; | |
355 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 356 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
357 | |
358 | if (idle_ticks < up_idle_ticks) { | |
dac1c1a5 | 359 | down_skip[cpu] = 0; |
790d76fa DJ |
360 | for_each_cpu_mask(j, policy->cpus) { |
361 | struct cpu_dbs_info_s *j_dbs_info; | |
362 | ||
363 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
364 | j_dbs_info->prev_cpu_idle_down = | |
365 | j_dbs_info->prev_cpu_idle_up; | |
366 | } | |
b9170836 DJ |
367 | /* if we are already at full speed then break out early */ |
368 | if (requested_freq[cpu] == policy->max) | |
369 | return; | |
370 | ||
371 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
372 | ||
373 | /* max freq cannot be less than 100. But who knows.... */ | |
374 | if (unlikely(freq_step == 0)) | |
375 | freq_step = 5; | |
376 | ||
377 | requested_freq[cpu] += freq_step; | |
378 | if (requested_freq[cpu] > policy->max) | |
379 | requested_freq[cpu] = policy->max; | |
380 | ||
381 | __cpufreq_driver_target(policy, requested_freq[cpu], | |
382 | CPUFREQ_RELATION_H); | |
b9170836 DJ |
383 | return; |
384 | } | |
385 | ||
386 | /* Check for frequency decrease */ | |
387 | down_skip[cpu]++; | |
388 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) | |
389 | return; | |
390 | ||
9c7d269b | 391 | idle_ticks = UINT_MAX; |
b9170836 | 392 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 393 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
394 | struct cpu_dbs_info_s *j_dbs_info; |
395 | ||
b9170836 | 396 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
2c906b31 | 397 | /* Check for frequency decrease */ |
dac1c1a5 | 398 | total_idle_ticks = j_dbs_info->prev_cpu_idle_up; |
b9170836 DJ |
399 | tmp_idle_ticks = total_idle_ticks - |
400 | j_dbs_info->prev_cpu_idle_down; | |
401 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
402 | ||
403 | if (tmp_idle_ticks < idle_ticks) | |
404 | idle_ticks = tmp_idle_ticks; | |
405 | } | |
406 | ||
407 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
408 | idle_ticks *= 100; | |
409 | down_skip[cpu] = 0; | |
410 | ||
411 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
412 | dbs_tuners_ins.sampling_down_factor; | |
413 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 414 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 415 | |
9c7d269b | 416 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
417 | /* |
418 | * if we are already at the lowest speed then break out early | |
b9170836 | 419 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
420 | * freq_step to be zero |
421 | */ | |
b9170836 DJ |
422 | if (requested_freq[cpu] == policy->min |
423 | || dbs_tuners_ins.freq_step == 0) | |
424 | return; | |
425 | ||
426 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
427 | ||
428 | /* max freq cannot be less than 100. But who knows.... */ | |
429 | if (unlikely(freq_step == 0)) | |
430 | freq_step = 5; | |
431 | ||
432 | requested_freq[cpu] -= freq_step; | |
433 | if (requested_freq[cpu] < policy->min) | |
434 | requested_freq[cpu] = policy->min; | |
435 | ||
2c906b31 AC |
436 | __cpufreq_driver_target(policy, requested_freq[cpu], |
437 | CPUFREQ_RELATION_H); | |
b9170836 DJ |
438 | return; |
439 | } | |
440 | } | |
441 | ||
442 | static void do_dbs_timer(void *data) | |
443 | { | |
444 | int i; | |
3fc54d37 | 445 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
446 | for_each_online_cpu(i) |
447 | dbs_check_cpu(i); | |
448 | schedule_delayed_work(&dbs_work, | |
449 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 450 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
451 | } |
452 | ||
453 | static inline void dbs_timer_init(void) | |
454 | { | |
455 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
456 | schedule_delayed_work(&dbs_work, | |
457 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
458 | return; | |
459 | } | |
460 | ||
461 | static inline void dbs_timer_exit(void) | |
462 | { | |
463 | cancel_delayed_work(&dbs_work); | |
464 | return; | |
465 | } | |
466 | ||
467 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
468 | unsigned int event) | |
469 | { | |
470 | unsigned int cpu = policy->cpu; | |
471 | struct cpu_dbs_info_s *this_dbs_info; | |
472 | unsigned int j; | |
473 | ||
474 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
475 | ||
476 | switch (event) { | |
477 | case CPUFREQ_GOV_START: | |
478 | if ((!cpu_online(cpu)) || | |
479 | (!policy->cur)) | |
480 | return -EINVAL; | |
481 | ||
482 | if (policy->cpuinfo.transition_latency > | |
483 | (TRANSITION_LATENCY_LIMIT * 1000)) | |
484 | return -EINVAL; | |
485 | if (this_dbs_info->enable) /* Already enabled */ | |
486 | break; | |
487 | ||
3fc54d37 | 488 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
489 | for_each_cpu_mask(j, policy->cpus) { |
490 | struct cpu_dbs_info_s *j_dbs_info; | |
491 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
492 | j_dbs_info->cur_policy = policy; | |
493 | ||
dac1c1a5 | 494 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
495 | j_dbs_info->prev_cpu_idle_down |
496 | = j_dbs_info->prev_cpu_idle_up; | |
497 | } | |
498 | this_dbs_info->enable = 1; | |
499 | sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
500 | dbs_enable++; | |
501 | /* | |
502 | * Start the timerschedule work, when this governor | |
503 | * is used for first time | |
504 | */ | |
505 | if (dbs_enable == 1) { | |
506 | unsigned int latency; | |
507 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
508 | latency = policy->cpuinfo.transition_latency / 1000; |
509 | if (latency == 0) | |
510 | latency = 1; | |
b9170836 | 511 | |
e8a02572 | 512 | def_sampling_rate = 10 * latency * |
b9170836 | 513 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
514 | |
515 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
516 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
517 | ||
b9170836 DJ |
518 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
519 | dbs_tuners_ins.ignore_nice = 0; | |
520 | dbs_tuners_ins.freq_step = 5; | |
521 | ||
522 | dbs_timer_init(); | |
523 | } | |
524 | ||
3fc54d37 | 525 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
526 | break; |
527 | ||
528 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 529 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
530 | this_dbs_info->enable = 0; |
531 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
532 | dbs_enable--; | |
533 | /* | |
534 | * Stop the timerschedule work, when this governor | |
535 | * is used for first time | |
536 | */ | |
537 | if (dbs_enable == 0) | |
538 | dbs_timer_exit(); | |
539 | ||
3fc54d37 | 540 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
541 | |
542 | break; | |
543 | ||
544 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 545 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
546 | if (policy->max < this_dbs_info->cur_policy->cur) |
547 | __cpufreq_driver_target( | |
548 | this_dbs_info->cur_policy, | |
549 | policy->max, CPUFREQ_RELATION_H); | |
550 | else if (policy->min > this_dbs_info->cur_policy->cur) | |
551 | __cpufreq_driver_target( | |
552 | this_dbs_info->cur_policy, | |
553 | policy->min, CPUFREQ_RELATION_L); | |
3fc54d37 | 554 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
555 | break; |
556 | } | |
557 | return 0; | |
558 | } | |
559 | ||
560 | static struct cpufreq_governor cpufreq_gov_dbs = { | |
561 | .name = "conservative", | |
562 | .governor = cpufreq_governor_dbs, | |
563 | .owner = THIS_MODULE, | |
564 | }; | |
565 | ||
566 | static int __init cpufreq_gov_dbs_init(void) | |
567 | { | |
568 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
569 | } | |
570 | ||
571 | static void __exit cpufreq_gov_dbs_exit(void) | |
572 | { | |
573 | /* Make sure that the scheduled work is indeed not running */ | |
574 | flush_scheduled_work(); | |
575 | ||
576 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
577 | } | |
578 | ||
579 | ||
580 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
581 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
582 | "Low Latency Frequency Transition capable processors " | |
583 | "optimised for use in a battery environment"); | |
584 | MODULE_LICENSE ("GPL"); | |
585 | ||
586 | module_init(cpufreq_gov_dbs_init); | |
587 | module_exit(cpufreq_gov_dbs_exit); |