Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * drivers/cpufreq/cpufreq_ondemand.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 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/module.h> | |
1da177e4 | 15 | #include <linux/init.h> |
1da177e4 | 16 | #include <linux/cpufreq.h> |
138a0128 | 17 | #include <linux/cpu.h> |
1da177e4 LT |
18 | #include <linux/jiffies.h> |
19 | #include <linux/kernel_stat.h> | |
3fc54d37 | 20 | #include <linux/mutex.h> |
80800913 | 21 | #include <linux/hrtimer.h> |
22 | #include <linux/tick.h> | |
23 | #include <linux/ktime.h> | |
9411b4ef | 24 | #include <linux/sched.h> |
1da177e4 LT |
25 | |
26 | /* | |
27 | * dbs is used in this file as a shortform for demandbased switching | |
28 | * It helps to keep variable names smaller, simpler | |
29 | */ | |
30 | ||
e9d95bf7 | 31 | #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) |
1da177e4 | 32 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
80800913 | 33 | #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) |
34 | #define MICRO_FREQUENCY_UP_THRESHOLD (95) | |
c29f1403 | 35 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
1da177e4 LT |
36 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
37 | ||
32ee8c3e DJ |
38 | /* |
39 | * The polling frequency of this governor depends on the capability of | |
1da177e4 | 40 | * the processor. Default polling frequency is 1000 times the transition |
32ee8c3e DJ |
41 | * latency of the processor. The governor will work on any processor with |
42 | * transition latency <= 10mS, using appropriate sampling | |
1da177e4 LT |
43 | * rate. |
44 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
45 | * this governor will not work. | |
46 | * All times here are in uS. | |
47 | */ | |
32ee8c3e | 48 | static unsigned int def_sampling_rate; |
df8b59be DJ |
49 | #define MIN_SAMPLING_RATE_RATIO (2) |
50 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
e08f5f5b GS |
51 | #define MIN_STAT_SAMPLING_RATE \ |
52 | (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
53 | #define MIN_SAMPLING_RATE \ | |
54 | (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
1da177e4 LT |
55 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
56 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) | |
1c256245 | 57 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
1da177e4 | 58 | |
c4028958 DH |
59 | static void do_dbs_timer(struct work_struct *work); |
60 | ||
61 | /* Sampling types */ | |
529af7a1 | 62 | enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; |
1da177e4 LT |
63 | |
64 | struct cpu_dbs_info_s { | |
ccb2fe20 VP |
65 | cputime64_t prev_cpu_idle; |
66 | cputime64_t prev_cpu_wall; | |
80800913 | 67 | cputime64_t prev_cpu_nice; |
32ee8c3e | 68 | struct cpufreq_policy *cur_policy; |
2b03f891 | 69 | struct delayed_work work; |
05ca0350 AS |
70 | struct cpufreq_frequency_table *freq_table; |
71 | unsigned int freq_lo; | |
72 | unsigned int freq_lo_jiffies; | |
73 | unsigned int freq_hi_jiffies; | |
529af7a1 VP |
74 | int cpu; |
75 | unsigned int enable:1, | |
2b03f891 | 76 | sample_type:1; |
1da177e4 LT |
77 | }; |
78 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
79 | ||
80 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
81 | ||
4ec223d0 VP |
82 | /* |
83 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug | |
84 | * lock and dbs_mutex. cpu_hotplug lock should always be held before | |
85 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock | |
86 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then | |
87 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock | |
88 | * is recursive for the same process. -Venki | |
89 | */ | |
ffac80e9 | 90 | static DEFINE_MUTEX(dbs_mutex); |
1da177e4 | 91 | |
2f8a835c | 92 | static struct workqueue_struct *kondemand_wq; |
6810b548 | 93 | |
05ca0350 | 94 | static struct dbs_tuners { |
32ee8c3e | 95 | unsigned int sampling_rate; |
32ee8c3e | 96 | unsigned int up_threshold; |
e9d95bf7 | 97 | unsigned int down_differential; |
32ee8c3e | 98 | unsigned int ignore_nice; |
05ca0350 AS |
99 | unsigned int powersave_bias; |
100 | } dbs_tuners_ins = { | |
32ee8c3e | 101 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
e9d95bf7 | 102 | .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, |
9cbad61b | 103 | .ignore_nice = 0, |
05ca0350 | 104 | .powersave_bias = 0, |
1da177e4 LT |
105 | }; |
106 | ||
80800913 | 107 | static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, |
108 | cputime64_t *wall) | |
dac1c1a5 | 109 | { |
ea487615 | 110 | cputime64_t idle_time; |
3430502d | 111 | cputime64_t cur_wall_time; |
ea487615 | 112 | cputime64_t busy_time; |
ccb2fe20 | 113 | |
3430502d | 114 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); |
ea487615 VP |
115 | busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user, |
116 | kstat_cpu(cpu).cpustat.system); | |
ccb2fe20 | 117 | |
ea487615 VP |
118 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq); |
119 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq); | |
120 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal); | |
1ca3abdb | 121 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice); |
ea487615 | 122 | |
3430502d | 123 | idle_time = cputime64_sub(cur_wall_time, busy_time); |
124 | if (wall) | |
125 | *wall = cur_wall_time; | |
126 | ||
ea487615 | 127 | return idle_time; |
dac1c1a5 DJ |
128 | } |
129 | ||
80800913 | 130 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) |
131 | { | |
132 | u64 idle_time = get_cpu_idle_time_us(cpu, wall); | |
133 | ||
134 | if (idle_time == -1ULL) | |
135 | return get_cpu_idle_time_jiffy(cpu, wall); | |
136 | ||
80800913 | 137 | return idle_time; |
138 | } | |
139 | ||
05ca0350 AS |
140 | /* |
141 | * Find right freq to be set now with powersave_bias on. | |
142 | * Returns the freq_hi to be used right now and will set freq_hi_jiffies, | |
143 | * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. | |
144 | */ | |
b5ecf60f AB |
145 | static unsigned int powersave_bias_target(struct cpufreq_policy *policy, |
146 | unsigned int freq_next, | |
147 | unsigned int relation) | |
05ca0350 AS |
148 | { |
149 | unsigned int freq_req, freq_reduc, freq_avg; | |
150 | unsigned int freq_hi, freq_lo; | |
151 | unsigned int index = 0; | |
152 | unsigned int jiffies_total, jiffies_hi, jiffies_lo; | |
153 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu); | |
154 | ||
155 | if (!dbs_info->freq_table) { | |
156 | dbs_info->freq_lo = 0; | |
157 | dbs_info->freq_lo_jiffies = 0; | |
158 | return freq_next; | |
159 | } | |
160 | ||
161 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, | |
162 | relation, &index); | |
163 | freq_req = dbs_info->freq_table[index].frequency; | |
164 | freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; | |
165 | freq_avg = freq_req - freq_reduc; | |
166 | ||
167 | /* Find freq bounds for freq_avg in freq_table */ | |
168 | index = 0; | |
169 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
170 | CPUFREQ_RELATION_H, &index); | |
171 | freq_lo = dbs_info->freq_table[index].frequency; | |
172 | index = 0; | |
173 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
174 | CPUFREQ_RELATION_L, &index); | |
175 | freq_hi = dbs_info->freq_table[index].frequency; | |
176 | ||
177 | /* Find out how long we have to be in hi and lo freqs */ | |
178 | if (freq_hi == freq_lo) { | |
179 | dbs_info->freq_lo = 0; | |
180 | dbs_info->freq_lo_jiffies = 0; | |
181 | return freq_lo; | |
182 | } | |
183 | jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
184 | jiffies_hi = (freq_avg - freq_lo) * jiffies_total; | |
185 | jiffies_hi += ((freq_hi - freq_lo) / 2); | |
186 | jiffies_hi /= (freq_hi - freq_lo); | |
187 | jiffies_lo = jiffies_total - jiffies_hi; | |
188 | dbs_info->freq_lo = freq_lo; | |
189 | dbs_info->freq_lo_jiffies = jiffies_lo; | |
190 | dbs_info->freq_hi_jiffies = jiffies_hi; | |
191 | return freq_hi; | |
192 | } | |
193 | ||
194 | static void ondemand_powersave_bias_init(void) | |
195 | { | |
196 | int i; | |
197 | for_each_online_cpu(i) { | |
198 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i); | |
199 | dbs_info->freq_table = cpufreq_frequency_get_table(i); | |
200 | dbs_info->freq_lo = 0; | |
201 | } | |
202 | } | |
203 | ||
1da177e4 LT |
204 | /************************** sysfs interface ************************/ |
205 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
206 | { | |
9411b4ef TR |
207 | static int print_once; |
208 | ||
209 | if (!print_once) { | |
210 | printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_max " | |
211 | "sysfs file is deprecated - used by: %s\n", | |
212 | current->comm); | |
213 | print_once = 1; | |
214 | } | |
2b03f891 | 215 | return sprintf(buf, "%u\n", MAX_SAMPLING_RATE); |
1da177e4 LT |
216 | } |
217 | ||
218 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
219 | { | |
9411b4ef TR |
220 | static int print_once; |
221 | ||
222 | if (!print_once) { | |
223 | printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_min " | |
224 | "sysfs file is deprecated - used by: %s\n", | |
225 | current->comm); | |
226 | print_once = 1; | |
227 | } | |
2b03f891 | 228 | return sprintf(buf, "%u\n", MIN_SAMPLING_RATE); |
1da177e4 LT |
229 | } |
230 | ||
32ee8c3e DJ |
231 | #define define_one_ro(_name) \ |
232 | static struct freq_attr _name = \ | |
1da177e4 LT |
233 | __ATTR(_name, 0444, show_##_name, NULL) |
234 | ||
235 | define_one_ro(sampling_rate_max); | |
236 | define_one_ro(sampling_rate_min); | |
237 | ||
238 | /* cpufreq_ondemand Governor Tunables */ | |
239 | #define show_one(file_name, object) \ | |
240 | static ssize_t show_##file_name \ | |
241 | (struct cpufreq_policy *unused, char *buf) \ | |
242 | { \ | |
243 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
244 | } | |
245 | show_one(sampling_rate, sampling_rate); | |
1da177e4 | 246 | show_one(up_threshold, up_threshold); |
001893cd | 247 | show_one(ignore_nice_load, ignore_nice); |
05ca0350 | 248 | show_one(powersave_bias, powersave_bias); |
1da177e4 | 249 | |
32ee8c3e | 250 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
1da177e4 LT |
251 | const char *buf, size_t count) |
252 | { | |
253 | unsigned int input; | |
254 | int ret; | |
ffac80e9 | 255 | ret = sscanf(buf, "%u", &input); |
1da177e4 | 256 | |
3fc54d37 | 257 | mutex_lock(&dbs_mutex); |
e08f5f5b GS |
258 | if (ret != 1 || input > MAX_SAMPLING_RATE |
259 | || input < MIN_SAMPLING_RATE) { | |
3fc54d37 | 260 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
261 | return -EINVAL; |
262 | } | |
263 | ||
264 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 265 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
266 | |
267 | return count; | |
268 | } | |
269 | ||
32ee8c3e | 270 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
1da177e4 LT |
271 | const char *buf, size_t count) |
272 | { | |
273 | unsigned int input; | |
274 | int ret; | |
ffac80e9 | 275 | ret = sscanf(buf, "%u", &input); |
1da177e4 | 276 | |
3fc54d37 | 277 | mutex_lock(&dbs_mutex); |
32ee8c3e | 278 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
c29f1403 | 279 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
3fc54d37 | 280 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
281 | return -EINVAL; |
282 | } | |
283 | ||
284 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 285 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
286 | |
287 | return count; | |
288 | } | |
289 | ||
001893cd | 290 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
3d5ee9e5 DJ |
291 | const char *buf, size_t count) |
292 | { | |
293 | unsigned int input; | |
294 | int ret; | |
295 | ||
296 | unsigned int j; | |
32ee8c3e | 297 | |
ffac80e9 | 298 | ret = sscanf(buf, "%u", &input); |
2b03f891 | 299 | if (ret != 1) |
3d5ee9e5 DJ |
300 | return -EINVAL; |
301 | ||
2b03f891 | 302 | if (input > 1) |
3d5ee9e5 | 303 | input = 1; |
32ee8c3e | 304 | |
3fc54d37 | 305 | mutex_lock(&dbs_mutex); |
2b03f891 | 306 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
3fc54d37 | 307 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
308 | return count; |
309 | } | |
310 | dbs_tuners_ins.ignore_nice = input; | |
311 | ||
ccb2fe20 | 312 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 313 | for_each_online_cpu(j) { |
ccb2fe20 VP |
314 | struct cpu_dbs_info_s *dbs_info; |
315 | dbs_info = &per_cpu(cpu_dbs_info, j); | |
3430502d | 316 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
317 | &dbs_info->prev_cpu_wall); | |
1ca3abdb VP |
318 | if (dbs_tuners_ins.ignore_nice) |
319 | dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
320 | ||
3d5ee9e5 | 321 | } |
3fc54d37 | 322 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
323 | |
324 | return count; | |
325 | } | |
326 | ||
05ca0350 AS |
327 | static ssize_t store_powersave_bias(struct cpufreq_policy *unused, |
328 | const char *buf, size_t count) | |
329 | { | |
330 | unsigned int input; | |
331 | int ret; | |
332 | ret = sscanf(buf, "%u", &input); | |
333 | ||
334 | if (ret != 1) | |
335 | return -EINVAL; | |
336 | ||
337 | if (input > 1000) | |
338 | input = 1000; | |
339 | ||
340 | mutex_lock(&dbs_mutex); | |
341 | dbs_tuners_ins.powersave_bias = input; | |
342 | ondemand_powersave_bias_init(); | |
343 | mutex_unlock(&dbs_mutex); | |
344 | ||
345 | return count; | |
346 | } | |
347 | ||
1da177e4 LT |
348 | #define define_one_rw(_name) \ |
349 | static struct freq_attr _name = \ | |
350 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
351 | ||
352 | define_one_rw(sampling_rate); | |
1da177e4 | 353 | define_one_rw(up_threshold); |
001893cd | 354 | define_one_rw(ignore_nice_load); |
05ca0350 | 355 | define_one_rw(powersave_bias); |
1da177e4 | 356 | |
2b03f891 | 357 | static struct attribute *dbs_attributes[] = { |
1da177e4 LT |
358 | &sampling_rate_max.attr, |
359 | &sampling_rate_min.attr, | |
360 | &sampling_rate.attr, | |
1da177e4 | 361 | &up_threshold.attr, |
001893cd | 362 | &ignore_nice_load.attr, |
05ca0350 | 363 | &powersave_bias.attr, |
1da177e4 LT |
364 | NULL |
365 | }; | |
366 | ||
367 | static struct attribute_group dbs_attr_group = { | |
368 | .attrs = dbs_attributes, | |
369 | .name = "ondemand", | |
370 | }; | |
371 | ||
372 | /************************** sysfs end ************************/ | |
373 | ||
2f8a835c | 374 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
1da177e4 | 375 | { |
c43aa3bd | 376 | unsigned int max_load_freq; |
1da177e4 LT |
377 | |
378 | struct cpufreq_policy *policy; | |
379 | unsigned int j; | |
380 | ||
1da177e4 LT |
381 | if (!this_dbs_info->enable) |
382 | return; | |
383 | ||
05ca0350 | 384 | this_dbs_info->freq_lo = 0; |
1da177e4 | 385 | policy = this_dbs_info->cur_policy; |
ea487615 | 386 | |
32ee8c3e | 387 | /* |
c29f1403 DJ |
388 | * Every sampling_rate, we check, if current idle time is less |
389 | * than 20% (default), then we try to increase frequency | |
ccb2fe20 | 390 | * Every sampling_rate, we look for a the lowest |
c29f1403 DJ |
391 | * frequency which can sustain the load while keeping idle time over |
392 | * 30%. If such a frequency exist, we try to decrease to this frequency. | |
1da177e4 | 393 | * |
32ee8c3e DJ |
394 | * Any frequency increase takes it to the maximum frequency. |
395 | * Frequency reduction happens at minimum steps of | |
396 | * 5% (default) of current frequency | |
1da177e4 LT |
397 | */ |
398 | ||
c43aa3bd | 399 | /* Get Absolute Load - in terms of freq */ |
400 | max_load_freq = 0; | |
401 | ||
835481d9 | 402 | for_each_cpu(j, policy->cpus) { |
1da177e4 | 403 | struct cpu_dbs_info_s *j_dbs_info; |
c43aa3bd | 404 | cputime64_t cur_wall_time, cur_idle_time; |
405 | unsigned int idle_time, wall_time; | |
406 | unsigned int load, load_freq; | |
407 | int freq_avg; | |
1da177e4 | 408 | |
1da177e4 | 409 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
3430502d | 410 | |
411 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
412 | ||
c43aa3bd | 413 | wall_time = (unsigned int) cputime64_sub(cur_wall_time, |
414 | j_dbs_info->prev_cpu_wall); | |
415 | j_dbs_info->prev_cpu_wall = cur_wall_time; | |
416 | ||
c43aa3bd | 417 | idle_time = (unsigned int) cputime64_sub(cur_idle_time, |
ccb2fe20 | 418 | j_dbs_info->prev_cpu_idle); |
c43aa3bd | 419 | j_dbs_info->prev_cpu_idle = cur_idle_time; |
1da177e4 | 420 | |
1ca3abdb VP |
421 | if (dbs_tuners_ins.ignore_nice) { |
422 | cputime64_t cur_nice; | |
423 | unsigned long cur_nice_jiffies; | |
424 | ||
425 | cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice, | |
426 | j_dbs_info->prev_cpu_nice); | |
427 | /* | |
428 | * Assumption: nice time between sampling periods will | |
429 | * be less than 2^32 jiffies for 32 bit sys | |
430 | */ | |
431 | cur_nice_jiffies = (unsigned long) | |
432 | cputime64_to_jiffies64(cur_nice); | |
433 | ||
434 | j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
435 | idle_time += jiffies_to_usecs(cur_nice_jiffies); | |
436 | } | |
437 | ||
3430502d | 438 | if (unlikely(!wall_time || wall_time < idle_time)) |
c43aa3bd | 439 | continue; |
c43aa3bd | 440 | |
441 | load = 100 * (wall_time - idle_time) / wall_time; | |
442 | ||
443 | freq_avg = __cpufreq_driver_getavg(policy, j); | |
444 | if (freq_avg <= 0) | |
445 | freq_avg = policy->cur; | |
446 | ||
447 | load_freq = load * freq_avg; | |
448 | if (load_freq > max_load_freq) | |
449 | max_load_freq = load_freq; | |
1da177e4 LT |
450 | } |
451 | ||
ccb2fe20 | 452 | /* Check for frequency increase */ |
c43aa3bd | 453 | if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { |
c11420a6 | 454 | /* if we are already at full speed then break out early */ |
05ca0350 AS |
455 | if (!dbs_tuners_ins.powersave_bias) { |
456 | if (policy->cur == policy->max) | |
457 | return; | |
458 | ||
459 | __cpufreq_driver_target(policy, policy->max, | |
460 | CPUFREQ_RELATION_H); | |
461 | } else { | |
462 | int freq = powersave_bias_target(policy, policy->max, | |
463 | CPUFREQ_RELATION_H); | |
464 | __cpufreq_driver_target(policy, freq, | |
465 | CPUFREQ_RELATION_L); | |
466 | } | |
1da177e4 LT |
467 | return; |
468 | } | |
469 | ||
470 | /* Check for frequency decrease */ | |
c29f1403 DJ |
471 | /* if we cannot reduce the frequency anymore, break out early */ |
472 | if (policy->cur == policy->min) | |
473 | return; | |
1da177e4 | 474 | |
c29f1403 DJ |
475 | /* |
476 | * The optimal frequency is the frequency that is the lowest that | |
477 | * can support the current CPU usage without triggering the up | |
478 | * policy. To be safe, we focus 10 points under the threshold. | |
479 | */ | |
e9d95bf7 | 480 | if (max_load_freq < |
481 | (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) * | |
482 | policy->cur) { | |
c43aa3bd | 483 | unsigned int freq_next; |
e9d95bf7 | 484 | freq_next = max_load_freq / |
485 | (dbs_tuners_ins.up_threshold - | |
486 | dbs_tuners_ins.down_differential); | |
dfde5d62 | 487 | |
05ca0350 AS |
488 | if (!dbs_tuners_ins.powersave_bias) { |
489 | __cpufreq_driver_target(policy, freq_next, | |
490 | CPUFREQ_RELATION_L); | |
491 | } else { | |
492 | int freq = powersave_bias_target(policy, freq_next, | |
493 | CPUFREQ_RELATION_L); | |
494 | __cpufreq_driver_target(policy, freq, | |
495 | CPUFREQ_RELATION_L); | |
496 | } | |
ccb2fe20 | 497 | } |
1da177e4 LT |
498 | } |
499 | ||
c4028958 | 500 | static void do_dbs_timer(struct work_struct *work) |
32ee8c3e | 501 | { |
529af7a1 VP |
502 | struct cpu_dbs_info_s *dbs_info = |
503 | container_of(work, struct cpu_dbs_info_s, work.work); | |
504 | unsigned int cpu = dbs_info->cpu; | |
505 | int sample_type = dbs_info->sample_type; | |
506 | ||
1ce28d6b AS |
507 | /* We want all CPUs to do sampling nearly on same jiffy */ |
508 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
c4028958 | 509 | |
1ce28d6b | 510 | delay -= jiffies % delay; |
2f8a835c | 511 | |
56463b78 | 512 | if (lock_policy_rwsem_write(cpu) < 0) |
2cd7cbdf | 513 | return; |
56463b78 VP |
514 | |
515 | if (!dbs_info->enable) { | |
516 | unlock_policy_rwsem_write(cpu); | |
517 | return; | |
518 | } | |
519 | ||
05ca0350 | 520 | /* Common NORMAL_SAMPLE setup */ |
c4028958 | 521 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
05ca0350 | 522 | if (!dbs_tuners_ins.powersave_bias || |
c4028958 | 523 | sample_type == DBS_NORMAL_SAMPLE) { |
05ca0350 | 524 | dbs_check_cpu(dbs_info); |
05ca0350 AS |
525 | if (dbs_info->freq_lo) { |
526 | /* Setup timer for SUB_SAMPLE */ | |
c4028958 | 527 | dbs_info->sample_type = DBS_SUB_SAMPLE; |
05ca0350 AS |
528 | delay = dbs_info->freq_hi_jiffies; |
529 | } | |
530 | } else { | |
531 | __cpufreq_driver_target(dbs_info->cur_policy, | |
2b03f891 | 532 | dbs_info->freq_lo, CPUFREQ_RELATION_H); |
05ca0350 | 533 | } |
1ce28d6b | 534 | queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay); |
56463b78 | 535 | unlock_policy_rwsem_write(cpu); |
32ee8c3e | 536 | } |
1da177e4 | 537 | |
529af7a1 | 538 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 539 | { |
1ce28d6b AS |
540 | /* We want all CPUs to do sampling nearly on same jiffy */ |
541 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
542 | delay -= jiffies % delay; | |
2f8a835c | 543 | |
c18a1483 | 544 | dbs_info->enable = 1; |
05ca0350 | 545 | ondemand_powersave_bias_init(); |
c4028958 | 546 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
28287033 | 547 | INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); |
529af7a1 | 548 | queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work, |
2b03f891 | 549 | delay); |
1da177e4 LT |
550 | } |
551 | ||
2cd7cbdf | 552 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 553 | { |
2cd7cbdf LT |
554 | dbs_info->enable = 0; |
555 | cancel_delayed_work(&dbs_info->work); | |
1da177e4 LT |
556 | } |
557 | ||
558 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
559 | unsigned int event) | |
560 | { | |
561 | unsigned int cpu = policy->cpu; | |
562 | struct cpu_dbs_info_s *this_dbs_info; | |
563 | unsigned int j; | |
914f7c31 | 564 | int rc; |
1da177e4 LT |
565 | |
566 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
567 | ||
568 | switch (event) { | |
569 | case CPUFREQ_GOV_START: | |
ffac80e9 | 570 | if ((!cpu_online(cpu)) || (!policy->cur)) |
1da177e4 LT |
571 | return -EINVAL; |
572 | ||
1da177e4 LT |
573 | if (this_dbs_info->enable) /* Already enabled */ |
574 | break; | |
32ee8c3e | 575 | |
3fc54d37 | 576 | mutex_lock(&dbs_mutex); |
2f8a835c | 577 | dbs_enable++; |
914f7c31 JG |
578 | |
579 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
580 | if (rc) { | |
914f7c31 JG |
581 | dbs_enable--; |
582 | mutex_unlock(&dbs_mutex); | |
583 | return rc; | |
584 | } | |
585 | ||
835481d9 | 586 | for_each_cpu(j, policy->cpus) { |
1da177e4 LT |
587 | struct cpu_dbs_info_s *j_dbs_info; |
588 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
589 | j_dbs_info->cur_policy = policy; | |
32ee8c3e | 590 | |
3430502d | 591 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
592 | &j_dbs_info->prev_cpu_wall); | |
1ca3abdb VP |
593 | if (dbs_tuners_ins.ignore_nice) { |
594 | j_dbs_info->prev_cpu_nice = | |
595 | kstat_cpu(j).cpustat.nice; | |
596 | } | |
1da177e4 | 597 | } |
529af7a1 | 598 | this_dbs_info->cpu = cpu; |
1da177e4 LT |
599 | /* |
600 | * Start the timerschedule work, when this governor | |
601 | * is used for first time | |
602 | */ | |
603 | if (dbs_enable == 1) { | |
604 | unsigned int latency; | |
605 | /* policy latency is in nS. Convert it to uS first */ | |
df8b59be DJ |
606 | latency = policy->cpuinfo.transition_latency / 1000; |
607 | if (latency == 0) | |
608 | latency = 1; | |
1da177e4 | 609 | |
df8b59be | 610 | def_sampling_rate = latency * |
1da177e4 | 611 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
df8b59be DJ |
612 | |
613 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
614 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
615 | ||
1da177e4 | 616 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
1da177e4 | 617 | } |
529af7a1 | 618 | dbs_timer_init(this_dbs_info); |
32ee8c3e | 619 | |
3fc54d37 | 620 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
621 | break; |
622 | ||
623 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 624 | mutex_lock(&dbs_mutex); |
2cd7cbdf | 625 | dbs_timer_exit(this_dbs_info); |
1da177e4 LT |
626 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
627 | dbs_enable--; | |
3fc54d37 | 628 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
629 | |
630 | break; | |
631 | ||
632 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 633 | mutex_lock(&dbs_mutex); |
1da177e4 | 634 | if (policy->max < this_dbs_info->cur_policy->cur) |
ffac80e9 | 635 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 636 | policy->max, CPUFREQ_RELATION_H); |
1da177e4 | 637 | else if (policy->min > this_dbs_info->cur_policy->cur) |
ffac80e9 | 638 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 639 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 640 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
641 | break; |
642 | } | |
643 | return 0; | |
644 | } | |
645 | ||
c4d14bc0 SW |
646 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
647 | static | |
648 | #endif | |
1c256245 TR |
649 | struct cpufreq_governor cpufreq_gov_ondemand = { |
650 | .name = "ondemand", | |
651 | .governor = cpufreq_governor_dbs, | |
652 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
653 | .owner = THIS_MODULE, | |
1da177e4 | 654 | }; |
1da177e4 LT |
655 | |
656 | static int __init cpufreq_gov_dbs_init(void) | |
657 | { | |
888a794c | 658 | int err; |
80800913 | 659 | cputime64_t wall; |
4f6e6b9f AR |
660 | u64 idle_time; |
661 | int cpu = get_cpu(); | |
80800913 | 662 | |
4f6e6b9f AR |
663 | idle_time = get_cpu_idle_time_us(cpu, &wall); |
664 | put_cpu(); | |
80800913 | 665 | if (idle_time != -1ULL) { |
666 | /* Idle micro accounting is supported. Use finer thresholds */ | |
667 | dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; | |
668 | dbs_tuners_ins.down_differential = | |
669 | MICRO_FREQUENCY_DOWN_DIFFERENTIAL; | |
670 | } | |
888a794c | 671 | |
56463b78 VP |
672 | kondemand_wq = create_workqueue("kondemand"); |
673 | if (!kondemand_wq) { | |
674 | printk(KERN_ERR "Creation of kondemand failed\n"); | |
675 | return -EFAULT; | |
676 | } | |
888a794c AM |
677 | err = cpufreq_register_governor(&cpufreq_gov_ondemand); |
678 | if (err) | |
679 | destroy_workqueue(kondemand_wq); | |
680 | ||
681 | return err; | |
1da177e4 LT |
682 | } |
683 | ||
684 | static void __exit cpufreq_gov_dbs_exit(void) | |
685 | { | |
1c256245 | 686 | cpufreq_unregister_governor(&cpufreq_gov_ondemand); |
56463b78 | 687 | destroy_workqueue(kondemand_wq); |
1da177e4 LT |
688 | } |
689 | ||
690 | ||
ffac80e9 VP |
691 | MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
692 | MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>"); | |
693 | MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
2b03f891 | 694 | "Low Latency Frequency Transition capable processors"); |
ffac80e9 | 695 | MODULE_LICENSE("GPL"); |
1da177e4 | 696 | |
6915719b JW |
697 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
698 | fs_initcall(cpufreq_gov_dbs_init); | |
699 | #else | |
1da177e4 | 700 | module_init(cpufreq_gov_dbs_init); |
6915719b | 701 | #endif |
1da177e4 | 702 | module_exit(cpufreq_gov_dbs_exit); |