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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) | |
112124ab TR |
55 | /* Above MIN_SAMPLING_RATE will vanish with its sysfs file soon |
56 | * Define the minimal settable sampling rate to the greater of: | |
57 | * - "HW transition latency" * 100 (same as default sampling / 10) | |
58 | * - MIN_STAT_SAMPLING_RATE | |
59 | * To avoid that userspace shoots itself. | |
60 | */ | |
61 | static unsigned int minimum_sampling_rate(void) | |
62 | { | |
63 | return max(def_sampling_rate / 10, MIN_STAT_SAMPLING_RATE); | |
64 | } | |
65 | ||
66 | /* This will also vanish soon with removing sampling_rate_max */ | |
1da177e4 | 67 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
112124ab | 68 | #define LATENCY_MULTIPLIER (1000) |
1c256245 | 69 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
1da177e4 | 70 | |
c4028958 DH |
71 | static void do_dbs_timer(struct work_struct *work); |
72 | ||
73 | /* Sampling types */ | |
529af7a1 | 74 | enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; |
1da177e4 LT |
75 | |
76 | struct cpu_dbs_info_s { | |
ccb2fe20 VP |
77 | cputime64_t prev_cpu_idle; |
78 | cputime64_t prev_cpu_wall; | |
80800913 | 79 | cputime64_t prev_cpu_nice; |
32ee8c3e | 80 | struct cpufreq_policy *cur_policy; |
2b03f891 | 81 | struct delayed_work work; |
05ca0350 AS |
82 | struct cpufreq_frequency_table *freq_table; |
83 | unsigned int freq_lo; | |
84 | unsigned int freq_lo_jiffies; | |
85 | unsigned int freq_hi_jiffies; | |
529af7a1 VP |
86 | int cpu; |
87 | unsigned int enable:1, | |
2b03f891 | 88 | sample_type:1; |
1da177e4 LT |
89 | }; |
90 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
91 | ||
92 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
93 | ||
4ec223d0 VP |
94 | /* |
95 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug | |
96 | * lock and dbs_mutex. cpu_hotplug lock should always be held before | |
97 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock | |
98 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then | |
99 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock | |
100 | * is recursive for the same process. -Venki | |
b14893a6 MD |
101 | * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, because it |
102 | * would deadlock with cancel_delayed_work_sync(), which is needed for proper | |
103 | * raceless workqueue teardown. | |
4ec223d0 | 104 | */ |
ffac80e9 | 105 | static DEFINE_MUTEX(dbs_mutex); |
1da177e4 | 106 | |
2f8a835c | 107 | static struct workqueue_struct *kondemand_wq; |
6810b548 | 108 | |
05ca0350 | 109 | static struct dbs_tuners { |
32ee8c3e | 110 | unsigned int sampling_rate; |
32ee8c3e | 111 | unsigned int up_threshold; |
e9d95bf7 | 112 | unsigned int down_differential; |
32ee8c3e | 113 | unsigned int ignore_nice; |
05ca0350 AS |
114 | unsigned int powersave_bias; |
115 | } dbs_tuners_ins = { | |
32ee8c3e | 116 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
e9d95bf7 | 117 | .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, |
9cbad61b | 118 | .ignore_nice = 0, |
05ca0350 | 119 | .powersave_bias = 0, |
1da177e4 LT |
120 | }; |
121 | ||
80800913 | 122 | static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, |
123 | cputime64_t *wall) | |
dac1c1a5 | 124 | { |
ea487615 | 125 | cputime64_t idle_time; |
3430502d | 126 | cputime64_t cur_wall_time; |
ea487615 | 127 | cputime64_t busy_time; |
ccb2fe20 | 128 | |
3430502d | 129 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); |
ea487615 VP |
130 | busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user, |
131 | kstat_cpu(cpu).cpustat.system); | |
ccb2fe20 | 132 | |
ea487615 VP |
133 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq); |
134 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq); | |
135 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal); | |
1ca3abdb | 136 | busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice); |
ea487615 | 137 | |
3430502d | 138 | idle_time = cputime64_sub(cur_wall_time, busy_time); |
139 | if (wall) | |
140 | *wall = cur_wall_time; | |
141 | ||
ea487615 | 142 | return idle_time; |
dac1c1a5 DJ |
143 | } |
144 | ||
80800913 | 145 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) |
146 | { | |
147 | u64 idle_time = get_cpu_idle_time_us(cpu, wall); | |
148 | ||
149 | if (idle_time == -1ULL) | |
150 | return get_cpu_idle_time_jiffy(cpu, wall); | |
151 | ||
80800913 | 152 | return idle_time; |
153 | } | |
154 | ||
05ca0350 AS |
155 | /* |
156 | * Find right freq to be set now with powersave_bias on. | |
157 | * Returns the freq_hi to be used right now and will set freq_hi_jiffies, | |
158 | * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. | |
159 | */ | |
b5ecf60f AB |
160 | static unsigned int powersave_bias_target(struct cpufreq_policy *policy, |
161 | unsigned int freq_next, | |
162 | unsigned int relation) | |
05ca0350 AS |
163 | { |
164 | unsigned int freq_req, freq_reduc, freq_avg; | |
165 | unsigned int freq_hi, freq_lo; | |
166 | unsigned int index = 0; | |
167 | unsigned int jiffies_total, jiffies_hi, jiffies_lo; | |
168 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu); | |
169 | ||
170 | if (!dbs_info->freq_table) { | |
171 | dbs_info->freq_lo = 0; | |
172 | dbs_info->freq_lo_jiffies = 0; | |
173 | return freq_next; | |
174 | } | |
175 | ||
176 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, | |
177 | relation, &index); | |
178 | freq_req = dbs_info->freq_table[index].frequency; | |
179 | freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; | |
180 | freq_avg = freq_req - freq_reduc; | |
181 | ||
182 | /* Find freq bounds for freq_avg in freq_table */ | |
183 | index = 0; | |
184 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
185 | CPUFREQ_RELATION_H, &index); | |
186 | freq_lo = dbs_info->freq_table[index].frequency; | |
187 | index = 0; | |
188 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
189 | CPUFREQ_RELATION_L, &index); | |
190 | freq_hi = dbs_info->freq_table[index].frequency; | |
191 | ||
192 | /* Find out how long we have to be in hi and lo freqs */ | |
193 | if (freq_hi == freq_lo) { | |
194 | dbs_info->freq_lo = 0; | |
195 | dbs_info->freq_lo_jiffies = 0; | |
196 | return freq_lo; | |
197 | } | |
198 | jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
199 | jiffies_hi = (freq_avg - freq_lo) * jiffies_total; | |
200 | jiffies_hi += ((freq_hi - freq_lo) / 2); | |
201 | jiffies_hi /= (freq_hi - freq_lo); | |
202 | jiffies_lo = jiffies_total - jiffies_hi; | |
203 | dbs_info->freq_lo = freq_lo; | |
204 | dbs_info->freq_lo_jiffies = jiffies_lo; | |
205 | dbs_info->freq_hi_jiffies = jiffies_hi; | |
206 | return freq_hi; | |
207 | } | |
208 | ||
209 | static void ondemand_powersave_bias_init(void) | |
210 | { | |
211 | int i; | |
212 | for_each_online_cpu(i) { | |
213 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i); | |
214 | dbs_info->freq_table = cpufreq_frequency_get_table(i); | |
215 | dbs_info->freq_lo = 0; | |
216 | } | |
217 | } | |
218 | ||
1da177e4 LT |
219 | /************************** sysfs interface ************************/ |
220 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
221 | { | |
9411b4ef TR |
222 | static int print_once; |
223 | ||
224 | if (!print_once) { | |
225 | printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_max " | |
226 | "sysfs file is deprecated - used by: %s\n", | |
227 | current->comm); | |
228 | print_once = 1; | |
229 | } | |
2b03f891 | 230 | return sprintf(buf, "%u\n", MAX_SAMPLING_RATE); |
1da177e4 LT |
231 | } |
232 | ||
233 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
234 | { | |
9411b4ef TR |
235 | static int print_once; |
236 | ||
237 | if (!print_once) { | |
238 | printk(KERN_INFO "CPUFREQ: ondemand sampling_rate_min " | |
239 | "sysfs file is deprecated - used by: %s\n", | |
240 | current->comm); | |
241 | print_once = 1; | |
242 | } | |
2b03f891 | 243 | return sprintf(buf, "%u\n", MIN_SAMPLING_RATE); |
1da177e4 LT |
244 | } |
245 | ||
32ee8c3e DJ |
246 | #define define_one_ro(_name) \ |
247 | static struct freq_attr _name = \ | |
1da177e4 LT |
248 | __ATTR(_name, 0444, show_##_name, NULL) |
249 | ||
250 | define_one_ro(sampling_rate_max); | |
251 | define_one_ro(sampling_rate_min); | |
252 | ||
253 | /* cpufreq_ondemand Governor Tunables */ | |
254 | #define show_one(file_name, object) \ | |
255 | static ssize_t show_##file_name \ | |
256 | (struct cpufreq_policy *unused, char *buf) \ | |
257 | { \ | |
258 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
259 | } | |
260 | show_one(sampling_rate, sampling_rate); | |
1da177e4 | 261 | show_one(up_threshold, up_threshold); |
001893cd | 262 | show_one(ignore_nice_load, ignore_nice); |
05ca0350 | 263 | show_one(powersave_bias, powersave_bias); |
1da177e4 | 264 | |
32ee8c3e | 265 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
1da177e4 LT |
266 | const char *buf, size_t count) |
267 | { | |
268 | unsigned int input; | |
269 | int ret; | |
ffac80e9 | 270 | ret = sscanf(buf, "%u", &input); |
1da177e4 | 271 | |
3fc54d37 | 272 | mutex_lock(&dbs_mutex); |
112124ab | 273 | if (ret != 1) { |
3fc54d37 | 274 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
275 | return -EINVAL; |
276 | } | |
112124ab | 277 | dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate()); |
3fc54d37 | 278 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
279 | |
280 | return count; | |
281 | } | |
282 | ||
32ee8c3e | 283 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
1da177e4 LT |
284 | const char *buf, size_t count) |
285 | { | |
286 | unsigned int input; | |
287 | int ret; | |
ffac80e9 | 288 | ret = sscanf(buf, "%u", &input); |
1da177e4 | 289 | |
3fc54d37 | 290 | mutex_lock(&dbs_mutex); |
32ee8c3e | 291 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
c29f1403 | 292 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
3fc54d37 | 293 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
294 | return -EINVAL; |
295 | } | |
296 | ||
297 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 298 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
299 | |
300 | return count; | |
301 | } | |
302 | ||
001893cd | 303 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
3d5ee9e5 DJ |
304 | const char *buf, size_t count) |
305 | { | |
306 | unsigned int input; | |
307 | int ret; | |
308 | ||
309 | unsigned int j; | |
32ee8c3e | 310 | |
ffac80e9 | 311 | ret = sscanf(buf, "%u", &input); |
2b03f891 | 312 | if (ret != 1) |
3d5ee9e5 DJ |
313 | return -EINVAL; |
314 | ||
2b03f891 | 315 | if (input > 1) |
3d5ee9e5 | 316 | input = 1; |
32ee8c3e | 317 | |
3fc54d37 | 318 | mutex_lock(&dbs_mutex); |
2b03f891 | 319 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
3fc54d37 | 320 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
321 | return count; |
322 | } | |
323 | dbs_tuners_ins.ignore_nice = input; | |
324 | ||
ccb2fe20 | 325 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 326 | for_each_online_cpu(j) { |
ccb2fe20 VP |
327 | struct cpu_dbs_info_s *dbs_info; |
328 | dbs_info = &per_cpu(cpu_dbs_info, j); | |
3430502d | 329 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
330 | &dbs_info->prev_cpu_wall); | |
1ca3abdb VP |
331 | if (dbs_tuners_ins.ignore_nice) |
332 | dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
333 | ||
3d5ee9e5 | 334 | } |
3fc54d37 | 335 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
336 | |
337 | return count; | |
338 | } | |
339 | ||
05ca0350 AS |
340 | static ssize_t store_powersave_bias(struct cpufreq_policy *unused, |
341 | const char *buf, size_t count) | |
342 | { | |
343 | unsigned int input; | |
344 | int ret; | |
345 | ret = sscanf(buf, "%u", &input); | |
346 | ||
347 | if (ret != 1) | |
348 | return -EINVAL; | |
349 | ||
350 | if (input > 1000) | |
351 | input = 1000; | |
352 | ||
353 | mutex_lock(&dbs_mutex); | |
354 | dbs_tuners_ins.powersave_bias = input; | |
355 | ondemand_powersave_bias_init(); | |
356 | mutex_unlock(&dbs_mutex); | |
357 | ||
358 | return count; | |
359 | } | |
360 | ||
1da177e4 LT |
361 | #define define_one_rw(_name) \ |
362 | static struct freq_attr _name = \ | |
363 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
364 | ||
365 | define_one_rw(sampling_rate); | |
1da177e4 | 366 | define_one_rw(up_threshold); |
001893cd | 367 | define_one_rw(ignore_nice_load); |
05ca0350 | 368 | define_one_rw(powersave_bias); |
1da177e4 | 369 | |
2b03f891 | 370 | static struct attribute *dbs_attributes[] = { |
1da177e4 LT |
371 | &sampling_rate_max.attr, |
372 | &sampling_rate_min.attr, | |
373 | &sampling_rate.attr, | |
1da177e4 | 374 | &up_threshold.attr, |
001893cd | 375 | &ignore_nice_load.attr, |
05ca0350 | 376 | &powersave_bias.attr, |
1da177e4 LT |
377 | NULL |
378 | }; | |
379 | ||
380 | static struct attribute_group dbs_attr_group = { | |
381 | .attrs = dbs_attributes, | |
382 | .name = "ondemand", | |
383 | }; | |
384 | ||
385 | /************************** sysfs end ************************/ | |
386 | ||
2f8a835c | 387 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
1da177e4 | 388 | { |
c43aa3bd | 389 | unsigned int max_load_freq; |
1da177e4 LT |
390 | |
391 | struct cpufreq_policy *policy; | |
392 | unsigned int j; | |
393 | ||
1da177e4 LT |
394 | if (!this_dbs_info->enable) |
395 | return; | |
396 | ||
05ca0350 | 397 | this_dbs_info->freq_lo = 0; |
1da177e4 | 398 | policy = this_dbs_info->cur_policy; |
ea487615 | 399 | |
32ee8c3e | 400 | /* |
c29f1403 DJ |
401 | * Every sampling_rate, we check, if current idle time is less |
402 | * than 20% (default), then we try to increase frequency | |
ccb2fe20 | 403 | * Every sampling_rate, we look for a the lowest |
c29f1403 DJ |
404 | * frequency which can sustain the load while keeping idle time over |
405 | * 30%. If such a frequency exist, we try to decrease to this frequency. | |
1da177e4 | 406 | * |
32ee8c3e DJ |
407 | * Any frequency increase takes it to the maximum frequency. |
408 | * Frequency reduction happens at minimum steps of | |
409 | * 5% (default) of current frequency | |
1da177e4 LT |
410 | */ |
411 | ||
c43aa3bd | 412 | /* Get Absolute Load - in terms of freq */ |
413 | max_load_freq = 0; | |
414 | ||
835481d9 | 415 | for_each_cpu(j, policy->cpus) { |
1da177e4 | 416 | struct cpu_dbs_info_s *j_dbs_info; |
c43aa3bd | 417 | cputime64_t cur_wall_time, cur_idle_time; |
418 | unsigned int idle_time, wall_time; | |
419 | unsigned int load, load_freq; | |
420 | int freq_avg; | |
1da177e4 | 421 | |
1da177e4 | 422 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
3430502d | 423 | |
424 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
425 | ||
c43aa3bd | 426 | wall_time = (unsigned int) cputime64_sub(cur_wall_time, |
427 | j_dbs_info->prev_cpu_wall); | |
428 | j_dbs_info->prev_cpu_wall = cur_wall_time; | |
429 | ||
c43aa3bd | 430 | idle_time = (unsigned int) cputime64_sub(cur_idle_time, |
ccb2fe20 | 431 | j_dbs_info->prev_cpu_idle); |
c43aa3bd | 432 | j_dbs_info->prev_cpu_idle = cur_idle_time; |
1da177e4 | 433 | |
1ca3abdb VP |
434 | if (dbs_tuners_ins.ignore_nice) { |
435 | cputime64_t cur_nice; | |
436 | unsigned long cur_nice_jiffies; | |
437 | ||
438 | cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice, | |
439 | j_dbs_info->prev_cpu_nice); | |
440 | /* | |
441 | * Assumption: nice time between sampling periods will | |
442 | * be less than 2^32 jiffies for 32 bit sys | |
443 | */ | |
444 | cur_nice_jiffies = (unsigned long) | |
445 | cputime64_to_jiffies64(cur_nice); | |
446 | ||
447 | j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; | |
448 | idle_time += jiffies_to_usecs(cur_nice_jiffies); | |
449 | } | |
450 | ||
3430502d | 451 | if (unlikely(!wall_time || wall_time < idle_time)) |
c43aa3bd | 452 | continue; |
c43aa3bd | 453 | |
454 | load = 100 * (wall_time - idle_time) / wall_time; | |
455 | ||
456 | freq_avg = __cpufreq_driver_getavg(policy, j); | |
457 | if (freq_avg <= 0) | |
458 | freq_avg = policy->cur; | |
459 | ||
460 | load_freq = load * freq_avg; | |
461 | if (load_freq > max_load_freq) | |
462 | max_load_freq = load_freq; | |
1da177e4 LT |
463 | } |
464 | ||
ccb2fe20 | 465 | /* Check for frequency increase */ |
c43aa3bd | 466 | if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { |
c11420a6 | 467 | /* if we are already at full speed then break out early */ |
05ca0350 AS |
468 | if (!dbs_tuners_ins.powersave_bias) { |
469 | if (policy->cur == policy->max) | |
470 | return; | |
471 | ||
472 | __cpufreq_driver_target(policy, policy->max, | |
473 | CPUFREQ_RELATION_H); | |
474 | } else { | |
475 | int freq = powersave_bias_target(policy, policy->max, | |
476 | CPUFREQ_RELATION_H); | |
477 | __cpufreq_driver_target(policy, freq, | |
478 | CPUFREQ_RELATION_L); | |
479 | } | |
1da177e4 LT |
480 | return; |
481 | } | |
482 | ||
483 | /* Check for frequency decrease */ | |
c29f1403 DJ |
484 | /* if we cannot reduce the frequency anymore, break out early */ |
485 | if (policy->cur == policy->min) | |
486 | return; | |
1da177e4 | 487 | |
c29f1403 DJ |
488 | /* |
489 | * The optimal frequency is the frequency that is the lowest that | |
490 | * can support the current CPU usage without triggering the up | |
491 | * policy. To be safe, we focus 10 points under the threshold. | |
492 | */ | |
e9d95bf7 | 493 | if (max_load_freq < |
494 | (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) * | |
495 | policy->cur) { | |
c43aa3bd | 496 | unsigned int freq_next; |
e9d95bf7 | 497 | freq_next = max_load_freq / |
498 | (dbs_tuners_ins.up_threshold - | |
499 | dbs_tuners_ins.down_differential); | |
dfde5d62 | 500 | |
05ca0350 AS |
501 | if (!dbs_tuners_ins.powersave_bias) { |
502 | __cpufreq_driver_target(policy, freq_next, | |
503 | CPUFREQ_RELATION_L); | |
504 | } else { | |
505 | int freq = powersave_bias_target(policy, freq_next, | |
506 | CPUFREQ_RELATION_L); | |
507 | __cpufreq_driver_target(policy, freq, | |
508 | CPUFREQ_RELATION_L); | |
509 | } | |
ccb2fe20 | 510 | } |
1da177e4 LT |
511 | } |
512 | ||
c4028958 | 513 | static void do_dbs_timer(struct work_struct *work) |
32ee8c3e | 514 | { |
529af7a1 VP |
515 | struct cpu_dbs_info_s *dbs_info = |
516 | container_of(work, struct cpu_dbs_info_s, work.work); | |
517 | unsigned int cpu = dbs_info->cpu; | |
518 | int sample_type = dbs_info->sample_type; | |
519 | ||
1ce28d6b AS |
520 | /* We want all CPUs to do sampling nearly on same jiffy */ |
521 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
c4028958 | 522 | |
1ce28d6b | 523 | delay -= jiffies % delay; |
2f8a835c | 524 | |
56463b78 | 525 | if (lock_policy_rwsem_write(cpu) < 0) |
2cd7cbdf | 526 | return; |
56463b78 VP |
527 | |
528 | if (!dbs_info->enable) { | |
529 | unlock_policy_rwsem_write(cpu); | |
530 | return; | |
531 | } | |
532 | ||
05ca0350 | 533 | /* Common NORMAL_SAMPLE setup */ |
c4028958 | 534 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
05ca0350 | 535 | if (!dbs_tuners_ins.powersave_bias || |
c4028958 | 536 | sample_type == DBS_NORMAL_SAMPLE) { |
05ca0350 | 537 | dbs_check_cpu(dbs_info); |
05ca0350 AS |
538 | if (dbs_info->freq_lo) { |
539 | /* Setup timer for SUB_SAMPLE */ | |
c4028958 | 540 | dbs_info->sample_type = DBS_SUB_SAMPLE; |
05ca0350 AS |
541 | delay = dbs_info->freq_hi_jiffies; |
542 | } | |
543 | } else { | |
544 | __cpufreq_driver_target(dbs_info->cur_policy, | |
2b03f891 | 545 | dbs_info->freq_lo, CPUFREQ_RELATION_H); |
05ca0350 | 546 | } |
1ce28d6b | 547 | queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay); |
56463b78 | 548 | unlock_policy_rwsem_write(cpu); |
32ee8c3e | 549 | } |
1da177e4 | 550 | |
529af7a1 | 551 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 552 | { |
1ce28d6b AS |
553 | /* We want all CPUs to do sampling nearly on same jiffy */ |
554 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
555 | delay -= jiffies % delay; | |
2f8a835c | 556 | |
c18a1483 | 557 | dbs_info->enable = 1; |
05ca0350 | 558 | ondemand_powersave_bias_init(); |
c4028958 | 559 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
28287033 | 560 | INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); |
529af7a1 | 561 | queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work, |
2b03f891 | 562 | delay); |
1da177e4 LT |
563 | } |
564 | ||
2cd7cbdf | 565 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 566 | { |
2cd7cbdf | 567 | dbs_info->enable = 0; |
b14893a6 | 568 | cancel_delayed_work_sync(&dbs_info->work); |
1da177e4 LT |
569 | } |
570 | ||
571 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
572 | unsigned int event) | |
573 | { | |
574 | unsigned int cpu = policy->cpu; | |
575 | struct cpu_dbs_info_s *this_dbs_info; | |
576 | unsigned int j; | |
914f7c31 | 577 | int rc; |
1da177e4 LT |
578 | |
579 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
580 | ||
581 | switch (event) { | |
582 | case CPUFREQ_GOV_START: | |
ffac80e9 | 583 | if ((!cpu_online(cpu)) || (!policy->cur)) |
1da177e4 LT |
584 | return -EINVAL; |
585 | ||
1da177e4 LT |
586 | if (this_dbs_info->enable) /* Already enabled */ |
587 | break; | |
32ee8c3e | 588 | |
3fc54d37 | 589 | mutex_lock(&dbs_mutex); |
2f8a835c | 590 | dbs_enable++; |
914f7c31 JG |
591 | |
592 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
593 | if (rc) { | |
914f7c31 JG |
594 | dbs_enable--; |
595 | mutex_unlock(&dbs_mutex); | |
596 | return rc; | |
597 | } | |
598 | ||
835481d9 | 599 | for_each_cpu(j, policy->cpus) { |
1da177e4 LT |
600 | struct cpu_dbs_info_s *j_dbs_info; |
601 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
602 | j_dbs_info->cur_policy = policy; | |
32ee8c3e | 603 | |
3430502d | 604 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
605 | &j_dbs_info->prev_cpu_wall); | |
1ca3abdb VP |
606 | if (dbs_tuners_ins.ignore_nice) { |
607 | j_dbs_info->prev_cpu_nice = | |
608 | kstat_cpu(j).cpustat.nice; | |
609 | } | |
1da177e4 | 610 | } |
529af7a1 | 611 | this_dbs_info->cpu = cpu; |
1da177e4 LT |
612 | /* |
613 | * Start the timerschedule work, when this governor | |
614 | * is used for first time | |
615 | */ | |
616 | if (dbs_enable == 1) { | |
617 | unsigned int latency; | |
618 | /* policy latency is in nS. Convert it to uS first */ | |
df8b59be DJ |
619 | latency = policy->cpuinfo.transition_latency / 1000; |
620 | if (latency == 0) | |
621 | latency = 1; | |
1da177e4 | 622 | |
112124ab TR |
623 | def_sampling_rate = |
624 | max(latency * LATENCY_MULTIPLIER, | |
625 | MIN_STAT_SAMPLING_RATE); | |
df8b59be | 626 | |
1da177e4 | 627 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
1da177e4 | 628 | } |
529af7a1 | 629 | dbs_timer_init(this_dbs_info); |
32ee8c3e | 630 | |
3fc54d37 | 631 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
632 | break; |
633 | ||
634 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 635 | mutex_lock(&dbs_mutex); |
2cd7cbdf | 636 | dbs_timer_exit(this_dbs_info); |
1da177e4 LT |
637 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
638 | dbs_enable--; | |
3fc54d37 | 639 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
640 | |
641 | break; | |
642 | ||
643 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 644 | mutex_lock(&dbs_mutex); |
1da177e4 | 645 | if (policy->max < this_dbs_info->cur_policy->cur) |
ffac80e9 | 646 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 647 | policy->max, CPUFREQ_RELATION_H); |
1da177e4 | 648 | else if (policy->min > this_dbs_info->cur_policy->cur) |
ffac80e9 | 649 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 650 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 651 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
652 | break; |
653 | } | |
654 | return 0; | |
655 | } | |
656 | ||
c4d14bc0 SW |
657 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
658 | static | |
659 | #endif | |
1c256245 TR |
660 | struct cpufreq_governor cpufreq_gov_ondemand = { |
661 | .name = "ondemand", | |
662 | .governor = cpufreq_governor_dbs, | |
663 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
664 | .owner = THIS_MODULE, | |
1da177e4 | 665 | }; |
1da177e4 LT |
666 | |
667 | static int __init cpufreq_gov_dbs_init(void) | |
668 | { | |
888a794c | 669 | int err; |
80800913 | 670 | cputime64_t wall; |
4f6e6b9f AR |
671 | u64 idle_time; |
672 | int cpu = get_cpu(); | |
80800913 | 673 | |
4f6e6b9f AR |
674 | idle_time = get_cpu_idle_time_us(cpu, &wall); |
675 | put_cpu(); | |
80800913 | 676 | if (idle_time != -1ULL) { |
677 | /* Idle micro accounting is supported. Use finer thresholds */ | |
678 | dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; | |
679 | dbs_tuners_ins.down_differential = | |
680 | MICRO_FREQUENCY_DOWN_DIFFERENTIAL; | |
681 | } | |
888a794c | 682 | |
56463b78 VP |
683 | kondemand_wq = create_workqueue("kondemand"); |
684 | if (!kondemand_wq) { | |
685 | printk(KERN_ERR "Creation of kondemand failed\n"); | |
686 | return -EFAULT; | |
687 | } | |
888a794c AM |
688 | err = cpufreq_register_governor(&cpufreq_gov_ondemand); |
689 | if (err) | |
690 | destroy_workqueue(kondemand_wq); | |
691 | ||
692 | return err; | |
1da177e4 LT |
693 | } |
694 | ||
695 | static void __exit cpufreq_gov_dbs_exit(void) | |
696 | { | |
1c256245 | 697 | cpufreq_unregister_governor(&cpufreq_gov_ondemand); |
56463b78 | 698 | destroy_workqueue(kondemand_wq); |
1da177e4 LT |
699 | } |
700 | ||
701 | ||
ffac80e9 VP |
702 | MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
703 | MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>"); | |
704 | MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
2b03f891 | 705 | "Low Latency Frequency Transition capable processors"); |
ffac80e9 | 706 | MODULE_LICENSE("GPL"); |
1da177e4 | 707 | |
6915719b JW |
708 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
709 | fs_initcall(cpufreq_gov_dbs_init); | |
710 | #else | |
1da177e4 | 711 | module_init(cpufreq_gov_dbs_init); |
6915719b | 712 | #endif |
1da177e4 | 713 | module_exit(cpufreq_gov_dbs_exit); |