Commit | Line | Data |
---|---|---|
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) |
3f78a9f7 DN |
33 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
34 | #define MAX_SAMPLING_DOWN_FACTOR (100000) | |
80800913 | 35 | #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) |
36 | #define MICRO_FREQUENCY_UP_THRESHOLD (95) | |
cef9615a | 37 | #define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000) |
c29f1403 | 38 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
1da177e4 LT |
39 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
40 | ||
32ee8c3e DJ |
41 | /* |
42 | * The polling frequency of this governor depends on the capability of | |
1da177e4 | 43 | * the processor. Default polling frequency is 1000 times the transition |
32ee8c3e DJ |
44 | * latency of the processor. The governor will work on any processor with |
45 | * transition latency <= 10mS, using appropriate sampling | |
1da177e4 LT |
46 | * rate. |
47 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
48 | * this governor will not work. | |
49 | * All times here are in uS. | |
50 | */ | |
df8b59be | 51 | #define MIN_SAMPLING_RATE_RATIO (2) |
112124ab | 52 | |
cef9615a TR |
53 | static unsigned int min_sampling_rate; |
54 | ||
112124ab | 55 | #define LATENCY_MULTIPLIER (1000) |
cef9615a | 56 | #define MIN_LATENCY_MULTIPLIER (100) |
1c256245 | 57 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
1da177e4 | 58 | |
c4028958 | 59 | static void do_dbs_timer(struct work_struct *work); |
0e625ac1 TR |
60 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
61 | unsigned int event); | |
62 | ||
63 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND | |
64 | static | |
65 | #endif | |
66 | struct cpufreq_governor cpufreq_gov_ondemand = { | |
67 | .name = "ondemand", | |
68 | .governor = cpufreq_governor_dbs, | |
69 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
70 | .owner = THIS_MODULE, | |
71 | }; | |
c4028958 DH |
72 | |
73 | /* Sampling types */ | |
529af7a1 | 74 | enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; |
1da177e4 LT |
75 | |
76 | struct cpu_dbs_info_s { | |
ccb2fe20 | 77 | cputime64_t prev_cpu_idle; |
6b8fcd90 | 78 | cputime64_t prev_cpu_iowait; |
ccb2fe20 | 79 | cputime64_t prev_cpu_wall; |
80800913 | 80 | cputime64_t prev_cpu_nice; |
32ee8c3e | 81 | struct cpufreq_policy *cur_policy; |
2b03f891 | 82 | struct delayed_work work; |
05ca0350 AS |
83 | struct cpufreq_frequency_table *freq_table; |
84 | unsigned int freq_lo; | |
85 | unsigned int freq_lo_jiffies; | |
86 | unsigned int freq_hi_jiffies; | |
3f78a9f7 | 87 | unsigned int rate_mult; |
529af7a1 | 88 | int cpu; |
5a75c828 | 89 | unsigned int sample_type:1; |
90 | /* | |
91 | * percpu mutex that serializes governor limit change with | |
92 | * do_dbs_timer invocation. We do not want do_dbs_timer to run | |
93 | * when user is changing the governor or limits. | |
94 | */ | |
95 | struct mutex timer_mutex; | |
1da177e4 | 96 | }; |
245b2e70 | 97 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info); |
1da177e4 LT |
98 | |
99 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
100 | ||
4ec223d0 | 101 | /* |
326c86de | 102 | * dbs_mutex protects dbs_enable in governor start/stop. |
4ec223d0 | 103 | */ |
ffac80e9 | 104 | static DEFINE_MUTEX(dbs_mutex); |
1da177e4 | 105 | |
05ca0350 | 106 | static struct dbs_tuners { |
32ee8c3e | 107 | unsigned int sampling_rate; |
32ee8c3e | 108 | unsigned int up_threshold; |
e9d95bf7 | 109 | unsigned int down_differential; |
32ee8c3e | 110 | unsigned int ignore_nice; |
3f78a9f7 | 111 | unsigned int sampling_down_factor; |
05ca0350 | 112 | unsigned int powersave_bias; |
19379b11 | 113 | unsigned int io_is_busy; |
05ca0350 | 114 | } dbs_tuners_ins = { |
32ee8c3e | 115 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
3f78a9f7 | 116 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, |
e9d95bf7 | 117 | .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, |
9cbad61b | 118 | .ignore_nice = 0, |
05ca0350 | 119 | .powersave_bias = 0, |
1da177e4 LT |
120 | }; |
121 | ||
3292beb3 | 122 | static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) |
dac1c1a5 | 123 | { |
3292beb3 | 124 | u64 idle_time; |
612ef28a | 125 | u64 cur_wall_time; |
3292beb3 | 126 | u64 busy_time; |
ccb2fe20 | 127 | |
3430502d | 128 | cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); |
ccb2fe20 | 129 | |
612ef28a MS |
130 | busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; |
131 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; | |
3292beb3 GC |
132 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; |
133 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; | |
134 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; | |
135 | busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; | |
64861634 MS |
136 | |
137 | idle_time = cur_wall_time - busy_time; | |
3430502d | 138 | if (wall) |
3292beb3 | 139 | *wall = jiffies_to_usecs(cur_wall_time); |
3430502d | 140 | |
3292beb3 | 141 | return jiffies_to_usecs(idle_time); |
dac1c1a5 DJ |
142 | } |
143 | ||
80800913 | 144 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) |
145 | { | |
6beea0cd | 146 | u64 idle_time = get_cpu_idle_time_us(cpu, NULL); |
80800913 | 147 | |
148 | if (idle_time == -1ULL) | |
149 | return get_cpu_idle_time_jiffy(cpu, wall); | |
6beea0cd MH |
150 | else |
151 | idle_time += get_cpu_iowait_time_us(cpu, wall); | |
80800913 | 152 | |
80800913 | 153 | return idle_time; |
154 | } | |
155 | ||
6b8fcd90 AV |
156 | static inline cputime64_t get_cpu_iowait_time(unsigned int cpu, cputime64_t *wall) |
157 | { | |
158 | u64 iowait_time = get_cpu_iowait_time_us(cpu, wall); | |
159 | ||
160 | if (iowait_time == -1ULL) | |
161 | return 0; | |
162 | ||
163 | return iowait_time; | |
164 | } | |
165 | ||
05ca0350 AS |
166 | /* |
167 | * Find right freq to be set now with powersave_bias on. | |
168 | * Returns the freq_hi to be used right now and will set freq_hi_jiffies, | |
169 | * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. | |
170 | */ | |
b5ecf60f AB |
171 | static unsigned int powersave_bias_target(struct cpufreq_policy *policy, |
172 | unsigned int freq_next, | |
173 | unsigned int relation) | |
05ca0350 AS |
174 | { |
175 | unsigned int freq_req, freq_reduc, freq_avg; | |
176 | unsigned int freq_hi, freq_lo; | |
177 | unsigned int index = 0; | |
178 | unsigned int jiffies_total, jiffies_hi, jiffies_lo; | |
245b2e70 TH |
179 | struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, |
180 | policy->cpu); | |
05ca0350 AS |
181 | |
182 | if (!dbs_info->freq_table) { | |
183 | dbs_info->freq_lo = 0; | |
184 | dbs_info->freq_lo_jiffies = 0; | |
185 | return freq_next; | |
186 | } | |
187 | ||
188 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, | |
189 | relation, &index); | |
190 | freq_req = dbs_info->freq_table[index].frequency; | |
191 | freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; | |
192 | freq_avg = freq_req - freq_reduc; | |
193 | ||
194 | /* Find freq bounds for freq_avg in freq_table */ | |
195 | index = 0; | |
196 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
197 | CPUFREQ_RELATION_H, &index); | |
198 | freq_lo = dbs_info->freq_table[index].frequency; | |
199 | index = 0; | |
200 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, | |
201 | CPUFREQ_RELATION_L, &index); | |
202 | freq_hi = dbs_info->freq_table[index].frequency; | |
203 | ||
204 | /* Find out how long we have to be in hi and lo freqs */ | |
205 | if (freq_hi == freq_lo) { | |
206 | dbs_info->freq_lo = 0; | |
207 | dbs_info->freq_lo_jiffies = 0; | |
208 | return freq_lo; | |
209 | } | |
210 | jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
211 | jiffies_hi = (freq_avg - freq_lo) * jiffies_total; | |
212 | jiffies_hi += ((freq_hi - freq_lo) / 2); | |
213 | jiffies_hi /= (freq_hi - freq_lo); | |
214 | jiffies_lo = jiffies_total - jiffies_hi; | |
215 | dbs_info->freq_lo = freq_lo; | |
216 | dbs_info->freq_lo_jiffies = jiffies_lo; | |
217 | dbs_info->freq_hi_jiffies = jiffies_hi; | |
218 | return freq_hi; | |
219 | } | |
220 | ||
5a75c828 | 221 | static void ondemand_powersave_bias_init_cpu(int cpu) |
222 | { | |
384be2b1 | 223 | struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu); |
5a75c828 | 224 | dbs_info->freq_table = cpufreq_frequency_get_table(cpu); |
225 | dbs_info->freq_lo = 0; | |
226 | } | |
227 | ||
05ca0350 AS |
228 | static void ondemand_powersave_bias_init(void) |
229 | { | |
230 | int i; | |
231 | for_each_online_cpu(i) { | |
5a75c828 | 232 | ondemand_powersave_bias_init_cpu(i); |
05ca0350 AS |
233 | } |
234 | } | |
235 | ||
1da177e4 | 236 | /************************** sysfs interface ************************/ |
0e625ac1 | 237 | |
0e625ac1 TR |
238 | static ssize_t show_sampling_rate_min(struct kobject *kobj, |
239 | struct attribute *attr, char *buf) | |
1da177e4 | 240 | { |
cef9615a | 241 | return sprintf(buf, "%u\n", min_sampling_rate); |
1da177e4 LT |
242 | } |
243 | ||
6dad2a29 | 244 | define_one_global_ro(sampling_rate_min); |
1da177e4 LT |
245 | |
246 | /* cpufreq_ondemand Governor Tunables */ | |
247 | #define show_one(file_name, object) \ | |
248 | static ssize_t show_##file_name \ | |
0e625ac1 | 249 | (struct kobject *kobj, struct attribute *attr, char *buf) \ |
1da177e4 LT |
250 | { \ |
251 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
252 | } | |
253 | show_one(sampling_rate, sampling_rate); | |
19379b11 | 254 | show_one(io_is_busy, io_is_busy); |
1da177e4 | 255 | show_one(up_threshold, up_threshold); |
3f78a9f7 | 256 | show_one(sampling_down_factor, sampling_down_factor); |
001893cd | 257 | show_one(ignore_nice_load, ignore_nice); |
05ca0350 | 258 | show_one(powersave_bias, powersave_bias); |
1da177e4 | 259 | |
fd0ef7a0 MH |
260 | /** |
261 | * update_sampling_rate - update sampling rate effective immediately if needed. | |
262 | * @new_rate: new sampling rate | |
263 | * | |
264 | * If new rate is smaller than the old, simply updaing | |
265 | * dbs_tuners_int.sampling_rate might not be appropriate. For example, | |
266 | * if the original sampling_rate was 1 second and the requested new sampling | |
267 | * rate is 10 ms because the user needs immediate reaction from ondemand | |
268 | * governor, but not sure if higher frequency will be required or not, | |
269 | * then, the governor may change the sampling rate too late; up to 1 second | |
270 | * later. Thus, if we are reducing the sampling rate, we need to make the | |
271 | * new value effective immediately. | |
272 | */ | |
273 | static void update_sampling_rate(unsigned int new_rate) | |
274 | { | |
275 | int cpu; | |
276 | ||
277 | dbs_tuners_ins.sampling_rate = new_rate | |
278 | = max(new_rate, min_sampling_rate); | |
279 | ||
280 | for_each_online_cpu(cpu) { | |
281 | struct cpufreq_policy *policy; | |
282 | struct cpu_dbs_info_s *dbs_info; | |
283 | unsigned long next_sampling, appointed_at; | |
284 | ||
285 | policy = cpufreq_cpu_get(cpu); | |
286 | if (!policy) | |
287 | continue; | |
288 | dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu); | |
289 | cpufreq_cpu_put(policy); | |
290 | ||
291 | mutex_lock(&dbs_info->timer_mutex); | |
292 | ||
293 | if (!delayed_work_pending(&dbs_info->work)) { | |
294 | mutex_unlock(&dbs_info->timer_mutex); | |
295 | continue; | |
296 | } | |
297 | ||
298 | next_sampling = jiffies + usecs_to_jiffies(new_rate); | |
299 | appointed_at = dbs_info->work.timer.expires; | |
300 | ||
301 | ||
302 | if (time_before(next_sampling, appointed_at)) { | |
303 | ||
304 | mutex_unlock(&dbs_info->timer_mutex); | |
305 | cancel_delayed_work_sync(&dbs_info->work); | |
306 | mutex_lock(&dbs_info->timer_mutex); | |
307 | ||
308 | schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, | |
309 | usecs_to_jiffies(new_rate)); | |
310 | ||
311 | } | |
312 | mutex_unlock(&dbs_info->timer_mutex); | |
313 | } | |
314 | } | |
315 | ||
0e625ac1 TR |
316 | static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, |
317 | const char *buf, size_t count) | |
1da177e4 LT |
318 | { |
319 | unsigned int input; | |
320 | int ret; | |
ffac80e9 | 321 | ret = sscanf(buf, "%u", &input); |
5a75c828 | 322 | if (ret != 1) |
323 | return -EINVAL; | |
fd0ef7a0 | 324 | update_sampling_rate(input); |
1da177e4 LT |
325 | return count; |
326 | } | |
327 | ||
19379b11 AV |
328 | static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b, |
329 | const char *buf, size_t count) | |
330 | { | |
331 | unsigned int input; | |
332 | int ret; | |
333 | ||
334 | ret = sscanf(buf, "%u", &input); | |
335 | if (ret != 1) | |
336 | return -EINVAL; | |
19379b11 | 337 | dbs_tuners_ins.io_is_busy = !!input; |
19379b11 AV |
338 | return count; |
339 | } | |
340 | ||
0e625ac1 TR |
341 | static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, |
342 | const char *buf, size_t count) | |
1da177e4 LT |
343 | { |
344 | unsigned int input; | |
345 | int ret; | |
ffac80e9 | 346 | ret = sscanf(buf, "%u", &input); |
1da177e4 | 347 | |
32ee8c3e | 348 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
c29f1403 | 349 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
1da177e4 LT |
350 | return -EINVAL; |
351 | } | |
1da177e4 | 352 | dbs_tuners_ins.up_threshold = input; |
1da177e4 LT |
353 | return count; |
354 | } | |
355 | ||
3f78a9f7 DN |
356 | static ssize_t store_sampling_down_factor(struct kobject *a, |
357 | struct attribute *b, const char *buf, size_t count) | |
358 | { | |
359 | unsigned int input, j; | |
360 | int ret; | |
361 | ret = sscanf(buf, "%u", &input); | |
362 | ||
363 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) | |
364 | return -EINVAL; | |
3f78a9f7 DN |
365 | dbs_tuners_ins.sampling_down_factor = input; |
366 | ||
367 | /* Reset down sampling multiplier in case it was active */ | |
368 | for_each_online_cpu(j) { | |
369 | struct cpu_dbs_info_s *dbs_info; | |
370 | dbs_info = &per_cpu(od_cpu_dbs_info, j); | |
371 | dbs_info->rate_mult = 1; | |
372 | } | |
3f78a9f7 DN |
373 | return count; |
374 | } | |
375 | ||
0e625ac1 TR |
376 | static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, |
377 | const char *buf, size_t count) | |
3d5ee9e5 DJ |
378 | { |
379 | unsigned int input; | |
380 | int ret; | |
381 | ||
382 | unsigned int j; | |
32ee8c3e | 383 | |
ffac80e9 | 384 | ret = sscanf(buf, "%u", &input); |
2b03f891 | 385 | if (ret != 1) |
3d5ee9e5 DJ |
386 | return -EINVAL; |
387 | ||
2b03f891 | 388 | if (input > 1) |
3d5ee9e5 | 389 | input = 1; |
32ee8c3e | 390 | |
2b03f891 | 391 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
3d5ee9e5 DJ |
392 | return count; |
393 | } | |
394 | dbs_tuners_ins.ignore_nice = input; | |
395 | ||
ccb2fe20 | 396 | /* we need to re-evaluate prev_cpu_idle */ |
dac1c1a5 | 397 | for_each_online_cpu(j) { |
ccb2fe20 | 398 | struct cpu_dbs_info_s *dbs_info; |
245b2e70 | 399 | dbs_info = &per_cpu(od_cpu_dbs_info, j); |
3430502d | 400 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
401 | &dbs_info->prev_cpu_wall); | |
1ca3abdb | 402 | if (dbs_tuners_ins.ignore_nice) |
3292beb3 | 403 | dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
1ca3abdb | 404 | |
3d5ee9e5 | 405 | } |
3d5ee9e5 DJ |
406 | return count; |
407 | } | |
408 | ||
0e625ac1 TR |
409 | static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b, |
410 | const char *buf, size_t count) | |
05ca0350 AS |
411 | { |
412 | unsigned int input; | |
413 | int ret; | |
414 | ret = sscanf(buf, "%u", &input); | |
415 | ||
416 | if (ret != 1) | |
417 | return -EINVAL; | |
418 | ||
419 | if (input > 1000) | |
420 | input = 1000; | |
421 | ||
05ca0350 AS |
422 | dbs_tuners_ins.powersave_bias = input; |
423 | ondemand_powersave_bias_init(); | |
05ca0350 AS |
424 | return count; |
425 | } | |
426 | ||
6dad2a29 | 427 | define_one_global_rw(sampling_rate); |
07d77759 | 428 | define_one_global_rw(io_is_busy); |
6dad2a29 | 429 | define_one_global_rw(up_threshold); |
3f78a9f7 | 430 | define_one_global_rw(sampling_down_factor); |
6dad2a29 BP |
431 | define_one_global_rw(ignore_nice_load); |
432 | define_one_global_rw(powersave_bias); | |
1da177e4 | 433 | |
2b03f891 | 434 | static struct attribute *dbs_attributes[] = { |
1da177e4 LT |
435 | &sampling_rate_min.attr, |
436 | &sampling_rate.attr, | |
1da177e4 | 437 | &up_threshold.attr, |
3f78a9f7 | 438 | &sampling_down_factor.attr, |
001893cd | 439 | &ignore_nice_load.attr, |
05ca0350 | 440 | &powersave_bias.attr, |
19379b11 | 441 | &io_is_busy.attr, |
1da177e4 LT |
442 | NULL |
443 | }; | |
444 | ||
445 | static struct attribute_group dbs_attr_group = { | |
446 | .attrs = dbs_attributes, | |
447 | .name = "ondemand", | |
448 | }; | |
449 | ||
450 | /************************** sysfs end ************************/ | |
451 | ||
00e299ff MC |
452 | static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq) |
453 | { | |
454 | if (dbs_tuners_ins.powersave_bias) | |
455 | freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H); | |
456 | else if (p->cur == p->max) | |
457 | return; | |
458 | ||
459 | __cpufreq_driver_target(p, freq, dbs_tuners_ins.powersave_bias ? | |
460 | CPUFREQ_RELATION_L : CPUFREQ_RELATION_H); | |
461 | } | |
462 | ||
2f8a835c | 463 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
1da177e4 | 464 | { |
c43aa3bd | 465 | unsigned int max_load_freq; |
1da177e4 LT |
466 | |
467 | struct cpufreq_policy *policy; | |
468 | unsigned int j; | |
469 | ||
05ca0350 | 470 | this_dbs_info->freq_lo = 0; |
1da177e4 | 471 | policy = this_dbs_info->cur_policy; |
ea487615 | 472 | |
32ee8c3e | 473 | /* |
c29f1403 DJ |
474 | * Every sampling_rate, we check, if current idle time is less |
475 | * than 20% (default), then we try to increase frequency | |
ccb2fe20 | 476 | * Every sampling_rate, we look for a the lowest |
c29f1403 DJ |
477 | * frequency which can sustain the load while keeping idle time over |
478 | * 30%. If such a frequency exist, we try to decrease to this frequency. | |
1da177e4 | 479 | * |
32ee8c3e DJ |
480 | * Any frequency increase takes it to the maximum frequency. |
481 | * Frequency reduction happens at minimum steps of | |
482 | * 5% (default) of current frequency | |
1da177e4 LT |
483 | */ |
484 | ||
c43aa3bd | 485 | /* Get Absolute Load - in terms of freq */ |
486 | max_load_freq = 0; | |
487 | ||
835481d9 | 488 | for_each_cpu(j, policy->cpus) { |
1da177e4 | 489 | struct cpu_dbs_info_s *j_dbs_info; |
6b8fcd90 AV |
490 | cputime64_t cur_wall_time, cur_idle_time, cur_iowait_time; |
491 | unsigned int idle_time, wall_time, iowait_time; | |
c43aa3bd | 492 | unsigned int load, load_freq; |
493 | int freq_avg; | |
1da177e4 | 494 | |
245b2e70 | 495 | j_dbs_info = &per_cpu(od_cpu_dbs_info, j); |
3430502d | 496 | |
497 | cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); | |
6b8fcd90 | 498 | cur_iowait_time = get_cpu_iowait_time(j, &cur_wall_time); |
3430502d | 499 | |
64861634 MS |
500 | wall_time = (unsigned int) |
501 | (cur_wall_time - j_dbs_info->prev_cpu_wall); | |
c43aa3bd | 502 | j_dbs_info->prev_cpu_wall = cur_wall_time; |
503 | ||
64861634 MS |
504 | idle_time = (unsigned int) |
505 | (cur_idle_time - j_dbs_info->prev_cpu_idle); | |
c43aa3bd | 506 | j_dbs_info->prev_cpu_idle = cur_idle_time; |
1da177e4 | 507 | |
64861634 MS |
508 | iowait_time = (unsigned int) |
509 | (cur_iowait_time - j_dbs_info->prev_cpu_iowait); | |
6b8fcd90 AV |
510 | j_dbs_info->prev_cpu_iowait = cur_iowait_time; |
511 | ||
1ca3abdb | 512 | if (dbs_tuners_ins.ignore_nice) { |
3292beb3 | 513 | u64 cur_nice; |
1ca3abdb VP |
514 | unsigned long cur_nice_jiffies; |
515 | ||
3292beb3 GC |
516 | cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - |
517 | j_dbs_info->prev_cpu_nice; | |
1ca3abdb VP |
518 | /* |
519 | * Assumption: nice time between sampling periods will | |
520 | * be less than 2^32 jiffies for 32 bit sys | |
521 | */ | |
522 | cur_nice_jiffies = (unsigned long) | |
523 | cputime64_to_jiffies64(cur_nice); | |
524 | ||
3292beb3 | 525 | j_dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
1ca3abdb VP |
526 | idle_time += jiffies_to_usecs(cur_nice_jiffies); |
527 | } | |
528 | ||
6b8fcd90 AV |
529 | /* |
530 | * For the purpose of ondemand, waiting for disk IO is an | |
531 | * indication that you're performance critical, and not that | |
532 | * the system is actually idle. So subtract the iowait time | |
533 | * from the cpu idle time. | |
534 | */ | |
535 | ||
19379b11 | 536 | if (dbs_tuners_ins.io_is_busy && idle_time >= iowait_time) |
6b8fcd90 AV |
537 | idle_time -= iowait_time; |
538 | ||
3430502d | 539 | if (unlikely(!wall_time || wall_time < idle_time)) |
c43aa3bd | 540 | continue; |
c43aa3bd | 541 | |
542 | load = 100 * (wall_time - idle_time) / wall_time; | |
543 | ||
544 | freq_avg = __cpufreq_driver_getavg(policy, j); | |
545 | if (freq_avg <= 0) | |
546 | freq_avg = policy->cur; | |
547 | ||
548 | load_freq = load * freq_avg; | |
549 | if (load_freq > max_load_freq) | |
550 | max_load_freq = load_freq; | |
1da177e4 LT |
551 | } |
552 | ||
ccb2fe20 | 553 | /* Check for frequency increase */ |
c43aa3bd | 554 | if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { |
3f78a9f7 DN |
555 | /* If switching to max speed, apply sampling_down_factor */ |
556 | if (policy->cur < policy->max) | |
557 | this_dbs_info->rate_mult = | |
558 | dbs_tuners_ins.sampling_down_factor; | |
00e299ff | 559 | dbs_freq_increase(policy, policy->max); |
1da177e4 LT |
560 | return; |
561 | } | |
562 | ||
563 | /* Check for frequency decrease */ | |
c29f1403 DJ |
564 | /* if we cannot reduce the frequency anymore, break out early */ |
565 | if (policy->cur == policy->min) | |
566 | return; | |
1da177e4 | 567 | |
c29f1403 DJ |
568 | /* |
569 | * The optimal frequency is the frequency that is the lowest that | |
570 | * can support the current CPU usage without triggering the up | |
571 | * policy. To be safe, we focus 10 points under the threshold. | |
572 | */ | |
e9d95bf7 | 573 | if (max_load_freq < |
574 | (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) * | |
575 | policy->cur) { | |
c43aa3bd | 576 | unsigned int freq_next; |
e9d95bf7 | 577 | freq_next = max_load_freq / |
578 | (dbs_tuners_ins.up_threshold - | |
579 | dbs_tuners_ins.down_differential); | |
dfde5d62 | 580 | |
3f78a9f7 DN |
581 | /* No longer fully busy, reset rate_mult */ |
582 | this_dbs_info->rate_mult = 1; | |
583 | ||
1dbf5888 NC |
584 | if (freq_next < policy->min) |
585 | freq_next = policy->min; | |
586 | ||
05ca0350 AS |
587 | if (!dbs_tuners_ins.powersave_bias) { |
588 | __cpufreq_driver_target(policy, freq_next, | |
589 | CPUFREQ_RELATION_L); | |
590 | } else { | |
591 | int freq = powersave_bias_target(policy, freq_next, | |
592 | CPUFREQ_RELATION_L); | |
593 | __cpufreq_driver_target(policy, freq, | |
594 | CPUFREQ_RELATION_L); | |
595 | } | |
ccb2fe20 | 596 | } |
1da177e4 LT |
597 | } |
598 | ||
c4028958 | 599 | static void do_dbs_timer(struct work_struct *work) |
32ee8c3e | 600 | { |
529af7a1 VP |
601 | struct cpu_dbs_info_s *dbs_info = |
602 | container_of(work, struct cpu_dbs_info_s, work.work); | |
603 | unsigned int cpu = dbs_info->cpu; | |
604 | int sample_type = dbs_info->sample_type; | |
605 | ||
5cb2c3bd | 606 | int delay; |
a665df9d | 607 | |
5a75c828 | 608 | mutex_lock(&dbs_info->timer_mutex); |
56463b78 | 609 | |
05ca0350 | 610 | /* Common NORMAL_SAMPLE setup */ |
c4028958 | 611 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
05ca0350 | 612 | if (!dbs_tuners_ins.powersave_bias || |
c4028958 | 613 | sample_type == DBS_NORMAL_SAMPLE) { |
05ca0350 | 614 | dbs_check_cpu(dbs_info); |
05ca0350 AS |
615 | if (dbs_info->freq_lo) { |
616 | /* Setup timer for SUB_SAMPLE */ | |
c4028958 | 617 | dbs_info->sample_type = DBS_SUB_SAMPLE; |
05ca0350 | 618 | delay = dbs_info->freq_hi_jiffies; |
5cb2c3bd VG |
619 | } else { |
620 | /* We want all CPUs to do sampling nearly on | |
621 | * same jiffy | |
622 | */ | |
623 | delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate | |
624 | * dbs_info->rate_mult); | |
625 | ||
626 | if (num_online_cpus() > 1) | |
627 | delay -= jiffies % delay; | |
05ca0350 AS |
628 | } |
629 | } else { | |
630 | __cpufreq_driver_target(dbs_info->cur_policy, | |
2b03f891 | 631 | dbs_info->freq_lo, CPUFREQ_RELATION_H); |
5cb2c3bd | 632 | delay = dbs_info->freq_lo_jiffies; |
05ca0350 | 633 | } |
57df5573 | 634 | schedule_delayed_work_on(cpu, &dbs_info->work, delay); |
5a75c828 | 635 | mutex_unlock(&dbs_info->timer_mutex); |
32ee8c3e | 636 | } |
1da177e4 | 637 | |
529af7a1 | 638 | static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 639 | { |
1ce28d6b AS |
640 | /* We want all CPUs to do sampling nearly on same jiffy */ |
641 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); | |
a665df9d JF |
642 | |
643 | if (num_online_cpus() > 1) | |
644 | delay -= jiffies % delay; | |
2f8a835c | 645 | |
c4028958 | 646 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
28287033 | 647 | INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); |
57df5573 | 648 | schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay); |
1da177e4 LT |
649 | } |
650 | ||
2cd7cbdf | 651 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
1da177e4 | 652 | { |
b14893a6 | 653 | cancel_delayed_work_sync(&dbs_info->work); |
1da177e4 LT |
654 | } |
655 | ||
19379b11 AV |
656 | /* |
657 | * Not all CPUs want IO time to be accounted as busy; this dependson how | |
658 | * efficient idling at a higher frequency/voltage is. | |
659 | * Pavel Machek says this is not so for various generations of AMD and old | |
660 | * Intel systems. | |
661 | * Mike Chan (androidlcom) calis this is also not true for ARM. | |
662 | * Because of this, whitelist specific known (series) of CPUs by default, and | |
663 | * leave all others up to the user. | |
664 | */ | |
665 | static int should_io_be_busy(void) | |
666 | { | |
667 | #if defined(CONFIG_X86) | |
668 | /* | |
669 | * For Intel, Core 2 (model 15) andl later have an efficient idle. | |
670 | */ | |
671 | if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && | |
672 | boot_cpu_data.x86 == 6 && | |
673 | boot_cpu_data.x86_model >= 15) | |
674 | return 1; | |
675 | #endif | |
676 | return 0; | |
677 | } | |
678 | ||
1da177e4 LT |
679 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
680 | unsigned int event) | |
681 | { | |
682 | unsigned int cpu = policy->cpu; | |
683 | struct cpu_dbs_info_s *this_dbs_info; | |
684 | unsigned int j; | |
914f7c31 | 685 | int rc; |
1da177e4 | 686 | |
245b2e70 | 687 | this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu); |
1da177e4 LT |
688 | |
689 | switch (event) { | |
690 | case CPUFREQ_GOV_START: | |
ffac80e9 | 691 | if ((!cpu_online(cpu)) || (!policy->cur)) |
1da177e4 LT |
692 | return -EINVAL; |
693 | ||
3fc54d37 | 694 | mutex_lock(&dbs_mutex); |
914f7c31 | 695 | |
5a75c828 | 696 | dbs_enable++; |
835481d9 | 697 | for_each_cpu(j, policy->cpus) { |
1da177e4 | 698 | struct cpu_dbs_info_s *j_dbs_info; |
245b2e70 | 699 | j_dbs_info = &per_cpu(od_cpu_dbs_info, j); |
1da177e4 | 700 | j_dbs_info->cur_policy = policy; |
32ee8c3e | 701 | |
3430502d | 702 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, |
703 | &j_dbs_info->prev_cpu_wall); | |
3292beb3 | 704 | if (dbs_tuners_ins.ignore_nice) |
1ca3abdb | 705 | j_dbs_info->prev_cpu_nice = |
3292beb3 | 706 | kcpustat_cpu(j).cpustat[CPUTIME_NICE]; |
1da177e4 | 707 | } |
529af7a1 | 708 | this_dbs_info->cpu = cpu; |
3f78a9f7 | 709 | this_dbs_info->rate_mult = 1; |
5a75c828 | 710 | ondemand_powersave_bias_init_cpu(cpu); |
1da177e4 LT |
711 | /* |
712 | * Start the timerschedule work, when this governor | |
713 | * is used for first time | |
714 | */ | |
715 | if (dbs_enable == 1) { | |
716 | unsigned int latency; | |
0e625ac1 TR |
717 | |
718 | rc = sysfs_create_group(cpufreq_global_kobject, | |
719 | &dbs_attr_group); | |
720 | if (rc) { | |
721 | mutex_unlock(&dbs_mutex); | |
722 | return rc; | |
723 | } | |
724 | ||
1da177e4 | 725 | /* policy latency is in nS. Convert it to uS first */ |
df8b59be DJ |
726 | latency = policy->cpuinfo.transition_latency / 1000; |
727 | if (latency == 0) | |
728 | latency = 1; | |
cef9615a TR |
729 | /* Bring kernel and HW constraints together */ |
730 | min_sampling_rate = max(min_sampling_rate, | |
731 | MIN_LATENCY_MULTIPLIER * latency); | |
732 | dbs_tuners_ins.sampling_rate = | |
733 | max(min_sampling_rate, | |
734 | latency * LATENCY_MULTIPLIER); | |
19379b11 | 735 | dbs_tuners_ins.io_is_busy = should_io_be_busy(); |
1da177e4 | 736 | } |
3fc54d37 | 737 | mutex_unlock(&dbs_mutex); |
7d26e2d5 | 738 | |
0e625ac1 | 739 | mutex_init(&this_dbs_info->timer_mutex); |
7d26e2d5 | 740 | dbs_timer_init(this_dbs_info); |
1da177e4 LT |
741 | break; |
742 | ||
743 | case CPUFREQ_GOV_STOP: | |
2cd7cbdf | 744 | dbs_timer_exit(this_dbs_info); |
7d26e2d5 | 745 | |
746 | mutex_lock(&dbs_mutex); | |
5a75c828 | 747 | mutex_destroy(&this_dbs_info->timer_mutex); |
1da177e4 | 748 | dbs_enable--; |
3fc54d37 | 749 | mutex_unlock(&dbs_mutex); |
0e625ac1 TR |
750 | if (!dbs_enable) |
751 | sysfs_remove_group(cpufreq_global_kobject, | |
752 | &dbs_attr_group); | |
1da177e4 LT |
753 | |
754 | break; | |
755 | ||
756 | case CPUFREQ_GOV_LIMITS: | |
5a75c828 | 757 | mutex_lock(&this_dbs_info->timer_mutex); |
1da177e4 | 758 | if (policy->max < this_dbs_info->cur_policy->cur) |
ffac80e9 | 759 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 760 | policy->max, CPUFREQ_RELATION_H); |
1da177e4 | 761 | else if (policy->min > this_dbs_info->cur_policy->cur) |
ffac80e9 | 762 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
2b03f891 | 763 | policy->min, CPUFREQ_RELATION_L); |
5a75c828 | 764 | mutex_unlock(&this_dbs_info->timer_mutex); |
1da177e4 LT |
765 | break; |
766 | } | |
767 | return 0; | |
768 | } | |
769 | ||
1da177e4 LT |
770 | static int __init cpufreq_gov_dbs_init(void) |
771 | { | |
4f6e6b9f AR |
772 | u64 idle_time; |
773 | int cpu = get_cpu(); | |
80800913 | 774 | |
21f2e3c8 | 775 | idle_time = get_cpu_idle_time_us(cpu, NULL); |
4f6e6b9f | 776 | put_cpu(); |
80800913 | 777 | if (idle_time != -1ULL) { |
778 | /* Idle micro accounting is supported. Use finer thresholds */ | |
779 | dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; | |
780 | dbs_tuners_ins.down_differential = | |
781 | MICRO_FREQUENCY_DOWN_DIFFERENTIAL; | |
cef9615a | 782 | /* |
bd74b32b | 783 | * In nohz/micro accounting case we set the minimum frequency |
cef9615a TR |
784 | * not depending on HZ, but fixed (very low). The deferred |
785 | * timer might skip some samples if idle/sleeping as needed. | |
786 | */ | |
787 | min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE; | |
788 | } else { | |
789 | /* For correct statistics, we need 10 ticks for each measure */ | |
790 | min_sampling_rate = | |
791 | MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); | |
80800913 | 792 | } |
888a794c | 793 | |
57df5573 | 794 | return cpufreq_register_governor(&cpufreq_gov_ondemand); |
1da177e4 LT |
795 | } |
796 | ||
797 | static void __exit cpufreq_gov_dbs_exit(void) | |
798 | { | |
1c256245 | 799 | cpufreq_unregister_governor(&cpufreq_gov_ondemand); |
1da177e4 LT |
800 | } |
801 | ||
802 | ||
ffac80e9 VP |
803 | MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
804 | MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>"); | |
805 | MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
2b03f891 | 806 | "Low Latency Frequency Transition capable processors"); |
ffac80e9 | 807 | MODULE_LICENSE("GPL"); |
1da177e4 | 808 | |
6915719b JW |
809 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
810 | fs_initcall(cpufreq_gov_dbs_init); | |
811 | #else | |
1da177e4 | 812 | module_init(cpufreq_gov_dbs_init); |
6915719b | 813 | #endif |
1da177e4 | 814 | module_exit(cpufreq_gov_dbs_exit); |