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 | ||
3292beb3 | 98 | static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) |
dac1c1a5 | 99 | { |
3292beb3 | 100 | u64 idle_time; |
612ef28a | 101 | u64 cur_wall_time; |
3292beb3 | 102 | u64 busy_time; |
8e677ce8 AC |
103 | |
104 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); | |
e08f5f5b | 105 | |
612ef28a MS |
106 | busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; |
107 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; | |
3292beb3 GC |
108 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; |
109 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; | |
110 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; | |
111 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; | |
64861634 MS |
112 | |
113 | idle_time = cur_wall_time - busy_time; | |
8e677ce8 | 114 | if (wall) |
3292beb3 | 115 | *wall = jiffies_to_usecs(cur_wall_time); |
e08f5f5b | 116 | |
3292beb3 | 117 | return jiffies_to_usecs(idle_time); |
8e677ce8 AC |
118 | } |
119 | ||
120 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) | |
121 | { | |
6beea0cd | 122 | u64 idle_time = get_cpu_idle_time_us(cpu, NULL); |
8e677ce8 AC |
123 | |
124 | if (idle_time == -1ULL) | |
125 | return get_cpu_idle_time_jiffy(cpu, wall); | |
6beea0cd MH |
126 | else |
127 | idle_time += get_cpu_iowait_time_us(cpu, wall); | |
8e677ce8 AC |
128 | |
129 | return idle_time; | |
dac1c1a5 DJ |
130 | } |
131 | ||
a8d7c3bc EO |
132 | /* keep track of frequency transitions */ |
133 | static int | |
134 | dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, | |
135 | void *data) | |
136 | { | |
137 | struct cpufreq_freqs *freq = data; | |
245b2e70 | 138 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cs_cpu_dbs_info, |
a8d7c3bc EO |
139 | freq->cpu); |
140 | ||
f407a08b AC |
141 | struct cpufreq_policy *policy; |
142 | ||
a8d7c3bc EO |
143 | if (!this_dbs_info->enable) |
144 | return 0; | |
145 | ||
f407a08b AC |
146 | policy = this_dbs_info->cur_policy; |
147 | ||
148 | /* | |
149 | * we only care if our internally tracked freq moves outside | |
150 | * the 'valid' ranges of freqency available to us otherwise | |
151 | * we do not change it | |
152 | */ | |
153 | if (this_dbs_info->requested_freq > policy->max | |
154 | || this_dbs_info->requested_freq < policy->min) | |
155 | this_dbs_info->requested_freq = freq->new; | |
a8d7c3bc EO |
156 | |
157 | return 0; | |
158 | } | |
159 | ||
160 | static struct notifier_block dbs_cpufreq_notifier_block = { | |
161 | .notifier_call = dbs_cpufreq_notifier | |
162 | }; | |
163 | ||
b9170836 | 164 | /************************** sysfs interface ************************/ |
49b015ce TR |
165 | static ssize_t show_sampling_rate_min(struct kobject *kobj, |
166 | struct attribute *attr, char *buf) | |
b9170836 | 167 | { |
cef9615a | 168 | return sprintf(buf, "%u\n", min_sampling_rate); |
b9170836 DJ |
169 | } |
170 | ||
6dad2a29 | 171 | define_one_global_ro(sampling_rate_min); |
b9170836 DJ |
172 | |
173 | /* cpufreq_conservative Governor Tunables */ | |
174 | #define show_one(file_name, object) \ | |
175 | static ssize_t show_##file_name \ | |
49b015ce | 176 | (struct kobject *kobj, struct attribute *attr, char *buf) \ |
b9170836 DJ |
177 | { \ |
178 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
179 | } | |
180 | show_one(sampling_rate, sampling_rate); | |
181 | show_one(sampling_down_factor, sampling_down_factor); | |
182 | show_one(up_threshold, up_threshold); | |
183 | show_one(down_threshold, down_threshold); | |
001893cd | 184 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
185 | show_one(freq_step, freq_step); |
186 | ||
49b015ce TR |
187 | static ssize_t store_sampling_down_factor(struct kobject *a, |
188 | struct attribute *b, | |
189 | const char *buf, size_t count) | |
b9170836 DJ |
190 | { |
191 | unsigned int input; | |
192 | int ret; | |
9acef487 | 193 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 194 | |
2c906b31 | 195 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
196 | return -EINVAL; |
197 | ||
b9170836 | 198 | dbs_tuners_ins.sampling_down_factor = input; |
b9170836 DJ |
199 | return count; |
200 | } | |
201 | ||
49b015ce TR |
202 | static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, |
203 | const char *buf, size_t count) | |
b9170836 DJ |
204 | { |
205 | unsigned int input; | |
206 | int ret; | |
9acef487 | 207 | ret = sscanf(buf, "%u", &input); |
b9170836 | 208 | |
8e677ce8 | 209 | if (ret != 1) |
b9170836 | 210 | return -EINVAL; |
8e677ce8 | 211 | |
cef9615a | 212 | dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate); |
b9170836 DJ |
213 | return count; |
214 | } | |
215 | ||
49b015ce TR |
216 | static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, |
217 | const char *buf, size_t count) | |
b9170836 DJ |
218 | { |
219 | unsigned int input; | |
220 | int ret; | |
9acef487 | 221 | ret = sscanf(buf, "%u", &input); |
b9170836 | 222 | |
9acef487 | 223 | if (ret != 1 || input > 100 || |
326c86de | 224 | input <= dbs_tuners_ins.down_threshold) |
b9170836 | 225 | return -EINVAL; |
b9170836 DJ |
226 | |
227 | dbs_tuners_ins.up_threshold = input; | |
b9170836 DJ |
228 | return count; |
229 | } | |
230 | ||
49b015ce TR |
231 | static ssize_t store_down_threshold(struct kobject *a, struct attribute *b, |
232 | const char *buf, size_t count) | |
b9170836 DJ |
233 | { |
234 | unsigned int input; | |
235 | int ret; | |
9acef487 | 236 | ret = sscanf(buf, "%u", &input); |
b9170836 | 237 | |
8e677ce8 AC |
238 | /* cannot be lower than 11 otherwise freq will not fall */ |
239 | if (ret != 1 || input < 11 || input > 100 || | |
326c86de | 240 | input >= dbs_tuners_ins.up_threshold) |
b9170836 | 241 | return -EINVAL; |
b9170836 DJ |
242 | |
243 | dbs_tuners_ins.down_threshold = input; | |
b9170836 DJ |
244 | return count; |
245 | } | |
246 | ||
49b015ce TR |
247 | static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, |
248 | const char *buf, size_t count) | |
b9170836 DJ |
249 | { |
250 | unsigned int input; | |
251 | int ret; | |
252 | ||
253 | unsigned int j; | |
18a7247d DJ |
254 | |
255 | ret = sscanf(buf, "%u", &input); | |
256 | if (ret != 1) | |
b9170836 DJ |
257 | return -EINVAL; |
258 | ||
18a7247d | 259 | if (input > 1) |
b9170836 | 260 | input = 1; |
18a7247d | 261 | |
326c86de | 262 | if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */ |
b9170836 | 263 | return count; |
326c86de | 264 | |
b9170836 DJ |
265 | dbs_tuners_ins.ignore_nice = input; |
266 | ||
8e677ce8 | 267 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 268 | for_each_online_cpu(j) { |
8e677ce8 | 269 | struct cpu_dbs_info_s *dbs_info; |
245b2e70 | 270 | dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
271 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
272 | &dbs_info->prev_cpu_wall); | |
273 | if (dbs_tuners_ins.ignore_nice) | |
3292beb3 | 274 | dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
b9170836 | 275 | } |
b9170836 DJ |
276 | return count; |
277 | } | |
278 | ||
49b015ce TR |
279 | static ssize_t store_freq_step(struct kobject *a, struct attribute *b, |
280 | const char *buf, size_t count) | |
b9170836 DJ |
281 | { |
282 | unsigned int input; | |
283 | int ret; | |
18a7247d | 284 | ret = sscanf(buf, "%u", &input); |
b9170836 | 285 | |
18a7247d | 286 | if (ret != 1) |
b9170836 DJ |
287 | return -EINVAL; |
288 | ||
18a7247d | 289 | if (input > 100) |
b9170836 | 290 | input = 100; |
18a7247d | 291 | |
b9170836 DJ |
292 | /* no need to test here if freq_step is zero as the user might actually |
293 | * want this, they would be crazy though :) */ | |
b9170836 | 294 | dbs_tuners_ins.freq_step = input; |
b9170836 DJ |
295 | return count; |
296 | } | |
297 | ||
6dad2a29 BP |
298 | define_one_global_rw(sampling_rate); |
299 | define_one_global_rw(sampling_down_factor); | |
300 | define_one_global_rw(up_threshold); | |
301 | define_one_global_rw(down_threshold); | |
302 | define_one_global_rw(ignore_nice_load); | |
303 | define_one_global_rw(freq_step); | |
b9170836 | 304 | |
9acef487 | 305 | static struct attribute *dbs_attributes[] = { |
b9170836 DJ |
306 | &sampling_rate_min.attr, |
307 | &sampling_rate.attr, | |
308 | &sampling_down_factor.attr, | |
309 | &up_threshold.attr, | |
310 | &down_threshold.attr, | |
001893cd | 311 | &ignore_nice_load.attr, |
b9170836 DJ |
312 | &freq_step.attr, |
313 | NULL | |
314 | }; | |
315 | ||
316 | static struct attribute_group dbs_attr_group = { | |
317 | .attrs = dbs_attributes, | |
318 | .name = "conservative", | |
319 | }; | |
320 | ||
321 | /************************** sysfs end ************************/ | |
322 | ||
8e677ce8 | 323 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
b9170836 | 324 | { |
8e677ce8 | 325 | unsigned int load = 0; |
fd187aaf | 326 | unsigned int max_load = 0; |
f068c04b | 327 | unsigned int freq_target; |
b9170836 | 328 | |
8e677ce8 AC |
329 | struct cpufreq_policy *policy; |
330 | unsigned int j; | |
b9170836 | 331 | |
08a28e2e AC |
332 | policy = this_dbs_info->cur_policy; |
333 | ||
18a7247d | 334 | /* |
8e677ce8 AC |
335 | * Every sampling_rate, we check, if current idle time is less |
336 | * than 20% (default), then we try to increase frequency | |
337 | * Every sampling_rate*sampling_down_factor, we check, if current | |
338 | * idle time is more than 80%, then we try to decrease frequency | |
b9170836 | 339 | * |
18a7247d DJ |
340 | * Any frequency increase takes it to the maximum frequency. |
341 | * Frequency reduction happens at minimum steps of | |
8e677ce8 | 342 | * 5% (default) of maximum frequency |
b9170836 DJ |
343 | */ |
344 | ||
8e677ce8 AC |
345 | /* Get Absolute Load */ |
346 | for_each_cpu(j, policy->cpus) { | |
347 | struct cpu_dbs_info_s *j_dbs_info; | |
348 | cputime64_t cur_wall_time, cur_idle_time; | |
349 | unsigned int idle_time, wall_time; | |
b9170836 | 350 | |
245b2e70 | 351 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
8e677ce8 AC |
352 | |
353 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
354 | ||
64861634 MS |
355 | wall_time = (unsigned int) |
356 | (cur_wall_time - j_dbs_info->prev_cpu_wall); | |
8e677ce8 | 357 | j_dbs_info->prev_cpu_wall = cur_wall_time; |
08a28e2e | 358 | |
64861634 MS |
359 | idle_time = (unsigned int) |
360 | (cur_idle_time - j_dbs_info->prev_cpu_idle); | |
8e677ce8 | 361 | j_dbs_info->prev_cpu_idle = cur_idle_time; |
b9170836 | 362 | |
8e677ce8 | 363 | if (dbs_tuners_ins.ignore_nice) { |
3292beb3 | 364 | u64 cur_nice; |
8e677ce8 AC |
365 | unsigned long cur_nice_jiffies; |
366 | ||
3292beb3 GC |
367 | cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - |
368 | j_dbs_info->prev_cpu_nice; | |
8e677ce8 AC |
369 | /* |
370 | * Assumption: nice time between sampling periods will | |
371 | * be less than 2^32 jiffies for 32 bit sys | |
372 | */ | |
373 | cur_nice_jiffies = (unsigned long) | |
374 | cputime64_to_jiffies64(cur_nice); | |
375 | ||
3292beb3 | 376 | j_dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
8e677ce8 AC |
377 | idle_time += jiffies_to_usecs(cur_nice_jiffies); |
378 | } | |
379 | ||
380 | if (unlikely(!wall_time || wall_time < idle_time)) | |
381 | continue; | |
382 | ||
383 | load = 100 * (wall_time - idle_time) / wall_time; | |
fd187aaf DB |
384 | |
385 | if (load > max_load) | |
386 | max_load = load; | |
8e677ce8 AC |
387 | } |
388 | ||
389 | /* | |
390 | * break out if we 'cannot' reduce the speed as the user might | |
391 | * want freq_step to be zero | |
392 | */ | |
393 | if (dbs_tuners_ins.freq_step == 0) | |
394 | return; | |
b9170836 | 395 | |
8e677ce8 | 396 | /* Check for frequency increase */ |
fd187aaf | 397 | if (max_load > dbs_tuners_ins.up_threshold) { |
a159b827 | 398 | this_dbs_info->down_skip = 0; |
790d76fa | 399 | |
b9170836 | 400 | /* if we are already at full speed then break out early */ |
a159b827 | 401 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 | 402 | return; |
18a7247d | 403 | |
f068c04b | 404 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 DJ |
405 | |
406 | /* max freq cannot be less than 100. But who knows.... */ | |
f068c04b DJ |
407 | if (unlikely(freq_target == 0)) |
408 | freq_target = 5; | |
18a7247d | 409 | |
f068c04b | 410 | this_dbs_info->requested_freq += freq_target; |
a159b827 AC |
411 | if (this_dbs_info->requested_freq > policy->max) |
412 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 413 | |
a159b827 | 414 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 415 | CPUFREQ_RELATION_H); |
b9170836 DJ |
416 | return; |
417 | } | |
418 | ||
8e677ce8 AC |
419 | /* |
420 | * The optimal frequency is the frequency that is the lowest that | |
421 | * can support the current CPU usage without triggering the up | |
422 | * policy. To be safe, we focus 10 points under the threshold. | |
423 | */ | |
fd187aaf | 424 | if (max_load < (dbs_tuners_ins.down_threshold - 10)) { |
f068c04b | 425 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 | 426 | |
f068c04b | 427 | this_dbs_info->requested_freq -= freq_target; |
a159b827 AC |
428 | if (this_dbs_info->requested_freq < policy->min) |
429 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 430 | |
8e677ce8 AC |
431 | /* |
432 | * if we cannot reduce the frequency anymore, break out early | |
433 | */ | |
434 | if (policy->cur == policy->min) | |
435 | return; | |
436 | ||
a159b827 | 437 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 438 | CPUFREQ_RELATION_H); |
b9170836 DJ |
439 | return; |
440 | } | |
441 | } | |
442 | ||
c4028958 | 443 | static void do_dbs_timer(struct work_struct *work) |
18a7247d | 444 | { |
8e677ce8 AC |
445 | struct cpu_dbs_info_s *dbs_info = |
446 | container_of(work, struct cpu_dbs_info_s, work.work); | |
447 | unsigned int cpu = dbs_info->cpu; | |
448 | ||
449 | /* We want all CPUs to do sampling nearly on same jiffy */ | |
450 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
451 | ||
452 | delay -= jiffies % delay; | |
453 | ||
ee88415c | 454 | mutex_lock(&dbs_info->timer_mutex); |
8e677ce8 AC |
455 | |
456 | dbs_check_cpu(dbs_info); | |
457 | ||
57df5573 | 458 | schedule_delayed_work_on(cpu, &dbs_info->work, delay); |
ee88415c | 459 | mutex_unlock(&dbs_info->timer_mutex); |
18a7247d | 460 | } |
b9170836 | 461 | |
8e677ce8 | 462 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 463 | { |
8e677ce8 AC |
464 | /* We want all CPUs to do sampling nearly on same jiffy */ |
465 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
466 | delay -= jiffies % delay; | |
467 | ||
468 | dbs_info->enable = 1; | |
469 | INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); | |
57df5573 | 470 | schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay); |
b9170836 DJ |
471 | } |
472 | ||
8e677ce8 | 473 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
b9170836 | 474 | { |
8e677ce8 | 475 | dbs_info->enable = 0; |
b253d2b2 | 476 | cancel_delayed_work_sync(&dbs_info->work); |
b9170836 DJ |
477 | } |
478 | ||
479 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
480 | unsigned int event) | |
481 | { | |
482 | unsigned int cpu = policy->cpu; | |
483 | struct cpu_dbs_info_s *this_dbs_info; | |
484 | unsigned int j; | |
914f7c31 | 485 | int rc; |
b9170836 | 486 | |
245b2e70 | 487 | this_dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); |
b9170836 DJ |
488 | |
489 | switch (event) { | |
490 | case CPUFREQ_GOV_START: | |
18a7247d | 491 | if ((!cpu_online(cpu)) || (!policy->cur)) |
b9170836 DJ |
492 | return -EINVAL; |
493 | ||
3fc54d37 | 494 | mutex_lock(&dbs_mutex); |
914f7c31 | 495 | |
835481d9 | 496 | for_each_cpu(j, policy->cpus) { |
b9170836 | 497 | struct cpu_dbs_info_s *j_dbs_info; |
245b2e70 | 498 | j_dbs_info = &per_cpu(cs_cpu_dbs_info, j); |
b9170836 | 499 | j_dbs_info->cur_policy = policy; |
18a7247d | 500 | |
8e677ce8 AC |
501 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
502 | &j_dbs_info->prev_cpu_wall); | |
3292beb3 | 503 | if (dbs_tuners_ins.ignore_nice) |
8e677ce8 | 504 | j_dbs_info->prev_cpu_nice = |
3292beb3 | 505 | kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
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); |