| 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> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/cpufreq.h> |
| 17 | #include <linux/cpu.h> |
| 18 | #include <linux/jiffies.h> |
| 19 | #include <linux/kernel_stat.h> |
| 20 | #include <linux/mutex.h> |
| 21 | |
| 22 | /* |
| 23 | * dbs is used in this file as a shortform for demandbased switching |
| 24 | * It helps to keep variable names smaller, simpler |
| 25 | */ |
| 26 | |
| 27 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
| 28 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
| 29 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
| 30 | |
| 31 | /* |
| 32 | * The polling frequency of this governor depends on the capability of |
| 33 | * the processor. Default polling frequency is 1000 times the transition |
| 34 | * latency of the processor. The governor will work on any processor with |
| 35 | * transition latency <= 10mS, using appropriate sampling |
| 36 | * rate. |
| 37 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) |
| 38 | * this governor will not work. |
| 39 | * All times here are in uS. |
| 40 | */ |
| 41 | static unsigned int def_sampling_rate; |
| 42 | #define MIN_SAMPLING_RATE_RATIO (2) |
| 43 | /* for correct statistics, we need at least 10 ticks between each measure */ |
| 44 | #define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) |
| 45 | #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) |
| 46 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
| 47 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
| 48 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
| 49 | |
| 50 | static void do_dbs_timer(struct work_struct *work); |
| 51 | |
| 52 | /* Sampling types */ |
| 53 | enum dbs_sample {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; |
| 54 | |
| 55 | struct cpu_dbs_info_s { |
| 56 | cputime64_t prev_cpu_idle; |
| 57 | cputime64_t prev_cpu_wall; |
| 58 | struct cpufreq_policy *cur_policy; |
| 59 | struct delayed_work work; |
| 60 | enum dbs_sample sample_type; |
| 61 | unsigned int enable; |
| 62 | struct cpufreq_frequency_table *freq_table; |
| 63 | unsigned int freq_lo; |
| 64 | unsigned int freq_lo_jiffies; |
| 65 | unsigned int freq_hi_jiffies; |
| 66 | }; |
| 67 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); |
| 68 | |
| 69 | static unsigned int dbs_enable; /* number of CPUs using this policy */ |
| 70 | |
| 71 | /* |
| 72 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug |
| 73 | * lock and dbs_mutex. cpu_hotplug lock should always be held before |
| 74 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock |
| 75 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then |
| 76 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock |
| 77 | * is recursive for the same process. -Venki |
| 78 | */ |
| 79 | static DEFINE_MUTEX(dbs_mutex); |
| 80 | |
| 81 | static struct workqueue_struct *kondemand_wq; |
| 82 | |
| 83 | static struct dbs_tuners { |
| 84 | unsigned int sampling_rate; |
| 85 | unsigned int up_threshold; |
| 86 | unsigned int ignore_nice; |
| 87 | unsigned int powersave_bias; |
| 88 | } dbs_tuners_ins = { |
| 89 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
| 90 | .ignore_nice = 0, |
| 91 | .powersave_bias = 0, |
| 92 | }; |
| 93 | |
| 94 | static inline cputime64_t get_cpu_idle_time(unsigned int cpu) |
| 95 | { |
| 96 | cputime64_t retval; |
| 97 | |
| 98 | retval = cputime64_add(kstat_cpu(cpu).cpustat.idle, |
| 99 | kstat_cpu(cpu).cpustat.iowait); |
| 100 | |
| 101 | if (dbs_tuners_ins.ignore_nice) |
| 102 | retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice); |
| 103 | |
| 104 | return retval; |
| 105 | } |
| 106 | |
| 107 | /* |
| 108 | * Find right freq to be set now with powersave_bias on. |
| 109 | * Returns the freq_hi to be used right now and will set freq_hi_jiffies, |
| 110 | * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. |
| 111 | */ |
| 112 | static unsigned int powersave_bias_target(struct cpufreq_policy *policy, |
| 113 | unsigned int freq_next, |
| 114 | unsigned int relation) |
| 115 | { |
| 116 | unsigned int freq_req, freq_reduc, freq_avg; |
| 117 | unsigned int freq_hi, freq_lo; |
| 118 | unsigned int index = 0; |
| 119 | unsigned int jiffies_total, jiffies_hi, jiffies_lo; |
| 120 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu); |
| 121 | |
| 122 | if (!dbs_info->freq_table) { |
| 123 | dbs_info->freq_lo = 0; |
| 124 | dbs_info->freq_lo_jiffies = 0; |
| 125 | return freq_next; |
| 126 | } |
| 127 | |
| 128 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, |
| 129 | relation, &index); |
| 130 | freq_req = dbs_info->freq_table[index].frequency; |
| 131 | freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; |
| 132 | freq_avg = freq_req - freq_reduc; |
| 133 | |
| 134 | /* Find freq bounds for freq_avg in freq_table */ |
| 135 | index = 0; |
| 136 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, |
| 137 | CPUFREQ_RELATION_H, &index); |
| 138 | freq_lo = dbs_info->freq_table[index].frequency; |
| 139 | index = 0; |
| 140 | cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, |
| 141 | CPUFREQ_RELATION_L, &index); |
| 142 | freq_hi = dbs_info->freq_table[index].frequency; |
| 143 | |
| 144 | /* Find out how long we have to be in hi and lo freqs */ |
| 145 | if (freq_hi == freq_lo) { |
| 146 | dbs_info->freq_lo = 0; |
| 147 | dbs_info->freq_lo_jiffies = 0; |
| 148 | return freq_lo; |
| 149 | } |
| 150 | jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| 151 | jiffies_hi = (freq_avg - freq_lo) * jiffies_total; |
| 152 | jiffies_hi += ((freq_hi - freq_lo) / 2); |
| 153 | jiffies_hi /= (freq_hi - freq_lo); |
| 154 | jiffies_lo = jiffies_total - jiffies_hi; |
| 155 | dbs_info->freq_lo = freq_lo; |
| 156 | dbs_info->freq_lo_jiffies = jiffies_lo; |
| 157 | dbs_info->freq_hi_jiffies = jiffies_hi; |
| 158 | return freq_hi; |
| 159 | } |
| 160 | |
| 161 | static void ondemand_powersave_bias_init(void) |
| 162 | { |
| 163 | int i; |
| 164 | for_each_online_cpu(i) { |
| 165 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i); |
| 166 | dbs_info->freq_table = cpufreq_frequency_get_table(i); |
| 167 | dbs_info->freq_lo = 0; |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | /************************** sysfs interface ************************/ |
| 172 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) |
| 173 | { |
| 174 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); |
| 175 | } |
| 176 | |
| 177 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) |
| 178 | { |
| 179 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); |
| 180 | } |
| 181 | |
| 182 | #define define_one_ro(_name) \ |
| 183 | static struct freq_attr _name = \ |
| 184 | __ATTR(_name, 0444, show_##_name, NULL) |
| 185 | |
| 186 | define_one_ro(sampling_rate_max); |
| 187 | define_one_ro(sampling_rate_min); |
| 188 | |
| 189 | /* cpufreq_ondemand Governor Tunables */ |
| 190 | #define show_one(file_name, object) \ |
| 191 | static ssize_t show_##file_name \ |
| 192 | (struct cpufreq_policy *unused, char *buf) \ |
| 193 | { \ |
| 194 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ |
| 195 | } |
| 196 | show_one(sampling_rate, sampling_rate); |
| 197 | show_one(up_threshold, up_threshold); |
| 198 | show_one(ignore_nice_load, ignore_nice); |
| 199 | show_one(powersave_bias, powersave_bias); |
| 200 | |
| 201 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
| 202 | const char *buf, size_t count) |
| 203 | { |
| 204 | unsigned int input; |
| 205 | int ret; |
| 206 | ret = sscanf(buf, "%u", &input); |
| 207 | |
| 208 | mutex_lock(&dbs_mutex); |
| 209 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
| 210 | mutex_unlock(&dbs_mutex); |
| 211 | return -EINVAL; |
| 212 | } |
| 213 | |
| 214 | dbs_tuners_ins.sampling_rate = input; |
| 215 | mutex_unlock(&dbs_mutex); |
| 216 | |
| 217 | return count; |
| 218 | } |
| 219 | |
| 220 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
| 221 | const char *buf, size_t count) |
| 222 | { |
| 223 | unsigned int input; |
| 224 | int ret; |
| 225 | ret = sscanf(buf, "%u", &input); |
| 226 | |
| 227 | mutex_lock(&dbs_mutex); |
| 228 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
| 229 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
| 230 | mutex_unlock(&dbs_mutex); |
| 231 | return -EINVAL; |
| 232 | } |
| 233 | |
| 234 | dbs_tuners_ins.up_threshold = input; |
| 235 | mutex_unlock(&dbs_mutex); |
| 236 | |
| 237 | return count; |
| 238 | } |
| 239 | |
| 240 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
| 241 | const char *buf, size_t count) |
| 242 | { |
| 243 | unsigned int input; |
| 244 | int ret; |
| 245 | |
| 246 | unsigned int j; |
| 247 | |
| 248 | ret = sscanf(buf, "%u", &input); |
| 249 | if ( ret != 1 ) |
| 250 | return -EINVAL; |
| 251 | |
| 252 | if ( input > 1 ) |
| 253 | input = 1; |
| 254 | |
| 255 | mutex_lock(&dbs_mutex); |
| 256 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
| 257 | mutex_unlock(&dbs_mutex); |
| 258 | return count; |
| 259 | } |
| 260 | dbs_tuners_ins.ignore_nice = input; |
| 261 | |
| 262 | /* we need to re-evaluate prev_cpu_idle */ |
| 263 | for_each_online_cpu(j) { |
| 264 | struct cpu_dbs_info_s *dbs_info; |
| 265 | dbs_info = &per_cpu(cpu_dbs_info, j); |
| 266 | dbs_info->prev_cpu_idle = get_cpu_idle_time(j); |
| 267 | dbs_info->prev_cpu_wall = get_jiffies_64(); |
| 268 | } |
| 269 | mutex_unlock(&dbs_mutex); |
| 270 | |
| 271 | return count; |
| 272 | } |
| 273 | |
| 274 | static ssize_t store_powersave_bias(struct cpufreq_policy *unused, |
| 275 | const char *buf, size_t count) |
| 276 | { |
| 277 | unsigned int input; |
| 278 | int ret; |
| 279 | ret = sscanf(buf, "%u", &input); |
| 280 | |
| 281 | if (ret != 1) |
| 282 | return -EINVAL; |
| 283 | |
| 284 | if (input > 1000) |
| 285 | input = 1000; |
| 286 | |
| 287 | mutex_lock(&dbs_mutex); |
| 288 | dbs_tuners_ins.powersave_bias = input; |
| 289 | ondemand_powersave_bias_init(); |
| 290 | mutex_unlock(&dbs_mutex); |
| 291 | |
| 292 | return count; |
| 293 | } |
| 294 | |
| 295 | #define define_one_rw(_name) \ |
| 296 | static struct freq_attr _name = \ |
| 297 | __ATTR(_name, 0644, show_##_name, store_##_name) |
| 298 | |
| 299 | define_one_rw(sampling_rate); |
| 300 | define_one_rw(up_threshold); |
| 301 | define_one_rw(ignore_nice_load); |
| 302 | define_one_rw(powersave_bias); |
| 303 | |
| 304 | static struct attribute * dbs_attributes[] = { |
| 305 | &sampling_rate_max.attr, |
| 306 | &sampling_rate_min.attr, |
| 307 | &sampling_rate.attr, |
| 308 | &up_threshold.attr, |
| 309 | &ignore_nice_load.attr, |
| 310 | &powersave_bias.attr, |
| 311 | NULL |
| 312 | }; |
| 313 | |
| 314 | static struct attribute_group dbs_attr_group = { |
| 315 | .attrs = dbs_attributes, |
| 316 | .name = "ondemand", |
| 317 | }; |
| 318 | |
| 319 | /************************** sysfs end ************************/ |
| 320 | |
| 321 | static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) |
| 322 | { |
| 323 | unsigned int idle_ticks, total_ticks; |
| 324 | unsigned int load; |
| 325 | cputime64_t cur_jiffies; |
| 326 | |
| 327 | struct cpufreq_policy *policy; |
| 328 | unsigned int j; |
| 329 | |
| 330 | if (!this_dbs_info->enable) |
| 331 | return; |
| 332 | |
| 333 | this_dbs_info->freq_lo = 0; |
| 334 | policy = this_dbs_info->cur_policy; |
| 335 | cur_jiffies = jiffies64_to_cputime64(get_jiffies_64()); |
| 336 | total_ticks = (unsigned int) cputime64_sub(cur_jiffies, |
| 337 | this_dbs_info->prev_cpu_wall); |
| 338 | this_dbs_info->prev_cpu_wall = cur_jiffies; |
| 339 | if (!total_ticks) |
| 340 | return; |
| 341 | /* |
| 342 | * Every sampling_rate, we check, if current idle time is less |
| 343 | * than 20% (default), then we try to increase frequency |
| 344 | * Every sampling_rate, we look for a the lowest |
| 345 | * frequency which can sustain the load while keeping idle time over |
| 346 | * 30%. If such a frequency exist, we try to decrease to this frequency. |
| 347 | * |
| 348 | * Any frequency increase takes it to the maximum frequency. |
| 349 | * Frequency reduction happens at minimum steps of |
| 350 | * 5% (default) of current frequency |
| 351 | */ |
| 352 | |
| 353 | /* Get Idle Time */ |
| 354 | idle_ticks = UINT_MAX; |
| 355 | for_each_cpu_mask(j, policy->cpus) { |
| 356 | cputime64_t total_idle_ticks; |
| 357 | unsigned int tmp_idle_ticks; |
| 358 | struct cpu_dbs_info_s *j_dbs_info; |
| 359 | |
| 360 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 361 | total_idle_ticks = get_cpu_idle_time(j); |
| 362 | tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks, |
| 363 | j_dbs_info->prev_cpu_idle); |
| 364 | j_dbs_info->prev_cpu_idle = total_idle_ticks; |
| 365 | |
| 366 | if (tmp_idle_ticks < idle_ticks) |
| 367 | idle_ticks = tmp_idle_ticks; |
| 368 | } |
| 369 | load = (100 * (total_ticks - idle_ticks)) / total_ticks; |
| 370 | |
| 371 | /* Check for frequency increase */ |
| 372 | if (load > dbs_tuners_ins.up_threshold) { |
| 373 | /* if we are already at full speed then break out early */ |
| 374 | if (!dbs_tuners_ins.powersave_bias) { |
| 375 | if (policy->cur == policy->max) |
| 376 | return; |
| 377 | |
| 378 | __cpufreq_driver_target(policy, policy->max, |
| 379 | CPUFREQ_RELATION_H); |
| 380 | } else { |
| 381 | int freq = powersave_bias_target(policy, policy->max, |
| 382 | CPUFREQ_RELATION_H); |
| 383 | __cpufreq_driver_target(policy, freq, |
| 384 | CPUFREQ_RELATION_L); |
| 385 | } |
| 386 | return; |
| 387 | } |
| 388 | |
| 389 | /* Check for frequency decrease */ |
| 390 | /* if we cannot reduce the frequency anymore, break out early */ |
| 391 | if (policy->cur == policy->min) |
| 392 | return; |
| 393 | |
| 394 | /* |
| 395 | * The optimal frequency is the frequency that is the lowest that |
| 396 | * can support the current CPU usage without triggering the up |
| 397 | * policy. To be safe, we focus 10 points under the threshold. |
| 398 | */ |
| 399 | if (load < (dbs_tuners_ins.up_threshold - 10)) { |
| 400 | unsigned int freq_next = (policy->cur * load) / |
| 401 | (dbs_tuners_ins.up_threshold - 10); |
| 402 | if (!dbs_tuners_ins.powersave_bias) { |
| 403 | __cpufreq_driver_target(policy, freq_next, |
| 404 | CPUFREQ_RELATION_L); |
| 405 | } else { |
| 406 | int freq = powersave_bias_target(policy, freq_next, |
| 407 | CPUFREQ_RELATION_L); |
| 408 | __cpufreq_driver_target(policy, freq, |
| 409 | CPUFREQ_RELATION_L); |
| 410 | } |
| 411 | } |
| 412 | } |
| 413 | |
| 414 | static void do_dbs_timer(struct work_struct *work) |
| 415 | { |
| 416 | unsigned int cpu = smp_processor_id(); |
| 417 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 418 | enum dbs_sample sample_type = dbs_info->sample_type; |
| 419 | /* We want all CPUs to do sampling nearly on same jiffy */ |
| 420 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| 421 | |
| 422 | /* Permit rescheduling of this work item */ |
| 423 | work_release(work); |
| 424 | |
| 425 | delay -= jiffies % delay; |
| 426 | |
| 427 | if (!dbs_info->enable) |
| 428 | return; |
| 429 | /* Common NORMAL_SAMPLE setup */ |
| 430 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
| 431 | if (!dbs_tuners_ins.powersave_bias || |
| 432 | sample_type == DBS_NORMAL_SAMPLE) { |
| 433 | lock_cpu_hotplug(); |
| 434 | dbs_check_cpu(dbs_info); |
| 435 | unlock_cpu_hotplug(); |
| 436 | if (dbs_info->freq_lo) { |
| 437 | /* Setup timer for SUB_SAMPLE */ |
| 438 | dbs_info->sample_type = DBS_SUB_SAMPLE; |
| 439 | delay = dbs_info->freq_hi_jiffies; |
| 440 | } |
| 441 | } else { |
| 442 | __cpufreq_driver_target(dbs_info->cur_policy, |
| 443 | dbs_info->freq_lo, |
| 444 | CPUFREQ_RELATION_H); |
| 445 | } |
| 446 | queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay); |
| 447 | } |
| 448 | |
| 449 | static inline void dbs_timer_init(unsigned int cpu) |
| 450 | { |
| 451 | struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 452 | /* We want all CPUs to do sampling nearly on same jiffy */ |
| 453 | int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| 454 | delay -= jiffies % delay; |
| 455 | |
| 456 | ondemand_powersave_bias_init(); |
| 457 | INIT_DELAYED_WORK_NAR(&dbs_info->work, do_dbs_timer); |
| 458 | dbs_info->sample_type = DBS_NORMAL_SAMPLE; |
| 459 | queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay); |
| 460 | } |
| 461 | |
| 462 | static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) |
| 463 | { |
| 464 | dbs_info->enable = 0; |
| 465 | cancel_delayed_work(&dbs_info->work); |
| 466 | flush_workqueue(kondemand_wq); |
| 467 | } |
| 468 | |
| 469 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| 470 | unsigned int event) |
| 471 | { |
| 472 | unsigned int cpu = policy->cpu; |
| 473 | struct cpu_dbs_info_s *this_dbs_info; |
| 474 | unsigned int j; |
| 475 | |
| 476 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 477 | |
| 478 | switch (event) { |
| 479 | case CPUFREQ_GOV_START: |
| 480 | if ((!cpu_online(cpu)) || (!policy->cur)) |
| 481 | return -EINVAL; |
| 482 | |
| 483 | if (policy->cpuinfo.transition_latency > |
| 484 | (TRANSITION_LATENCY_LIMIT * 1000)) { |
| 485 | printk(KERN_WARNING "ondemand governor failed to load " |
| 486 | "due to too long transition latency\n"); |
| 487 | return -EINVAL; |
| 488 | } |
| 489 | if (this_dbs_info->enable) /* Already enabled */ |
| 490 | break; |
| 491 | |
| 492 | mutex_lock(&dbs_mutex); |
| 493 | dbs_enable++; |
| 494 | if (dbs_enable == 1) { |
| 495 | kondemand_wq = create_workqueue("kondemand"); |
| 496 | if (!kondemand_wq) { |
| 497 | printk(KERN_ERR "Creation of kondemand failed\n"); |
| 498 | dbs_enable--; |
| 499 | mutex_unlock(&dbs_mutex); |
| 500 | return -ENOSPC; |
| 501 | } |
| 502 | } |
| 503 | for_each_cpu_mask(j, policy->cpus) { |
| 504 | struct cpu_dbs_info_s *j_dbs_info; |
| 505 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 506 | j_dbs_info->cur_policy = policy; |
| 507 | |
| 508 | j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j); |
| 509 | j_dbs_info->prev_cpu_wall = get_jiffies_64(); |
| 510 | } |
| 511 | this_dbs_info->enable = 1; |
| 512 | sysfs_create_group(&policy->kobj, &dbs_attr_group); |
| 513 | /* |
| 514 | * Start the timerschedule work, when this governor |
| 515 | * is used for first time |
| 516 | */ |
| 517 | if (dbs_enable == 1) { |
| 518 | unsigned int latency; |
| 519 | /* policy latency is in nS. Convert it to uS first */ |
| 520 | latency = policy->cpuinfo.transition_latency / 1000; |
| 521 | if (latency == 0) |
| 522 | latency = 1; |
| 523 | |
| 524 | def_sampling_rate = latency * |
| 525 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
| 526 | |
| 527 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) |
| 528 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; |
| 529 | |
| 530 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
| 531 | } |
| 532 | dbs_timer_init(policy->cpu); |
| 533 | |
| 534 | mutex_unlock(&dbs_mutex); |
| 535 | break; |
| 536 | |
| 537 | case CPUFREQ_GOV_STOP: |
| 538 | mutex_lock(&dbs_mutex); |
| 539 | dbs_timer_exit(this_dbs_info); |
| 540 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
| 541 | dbs_enable--; |
| 542 | if (dbs_enable == 0) |
| 543 | destroy_workqueue(kondemand_wq); |
| 544 | |
| 545 | mutex_unlock(&dbs_mutex); |
| 546 | |
| 547 | break; |
| 548 | |
| 549 | case CPUFREQ_GOV_LIMITS: |
| 550 | mutex_lock(&dbs_mutex); |
| 551 | if (policy->max < this_dbs_info->cur_policy->cur) |
| 552 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
| 553 | policy->max, |
| 554 | CPUFREQ_RELATION_H); |
| 555 | else if (policy->min > this_dbs_info->cur_policy->cur) |
| 556 | __cpufreq_driver_target(this_dbs_info->cur_policy, |
| 557 | policy->min, |
| 558 | CPUFREQ_RELATION_L); |
| 559 | mutex_unlock(&dbs_mutex); |
| 560 | break; |
| 561 | } |
| 562 | return 0; |
| 563 | } |
| 564 | |
| 565 | static struct cpufreq_governor cpufreq_gov_dbs = { |
| 566 | .name = "ondemand", |
| 567 | .governor = cpufreq_governor_dbs, |
| 568 | .owner = THIS_MODULE, |
| 569 | }; |
| 570 | |
| 571 | static int __init cpufreq_gov_dbs_init(void) |
| 572 | { |
| 573 | return cpufreq_register_governor(&cpufreq_gov_dbs); |
| 574 | } |
| 575 | |
| 576 | static void __exit cpufreq_gov_dbs_exit(void) |
| 577 | { |
| 578 | cpufreq_unregister_governor(&cpufreq_gov_dbs); |
| 579 | } |
| 580 | |
| 581 | |
| 582 | MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
| 583 | MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>"); |
| 584 | MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " |
| 585 | "Low Latency Frequency Transition capable processors"); |
| 586 | MODULE_LICENSE("GPL"); |
| 587 | |
| 588 | module_init(cpufreq_gov_dbs_init); |
| 589 | module_exit(cpufreq_gov_dbs_exit); |