err.no Git - linux-2.6/blob - drivers/cpufreq/cpufreq_ondemand.c

   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                  \
  45                         (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
  46 #define MIN_SAMPLING_RATE                       \
  47                         (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
  48 #define MAX_SAMPLING_RATE                       (500 * def_sampling_rate)
  49 #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER    (1000)
  50 #define TRANSITION_LATENCY_LIMIT                (10 * 1000)
  51
  52 static void do_dbs_timer(void *data);
  53
  54 struct cpu_dbs_info_s {
  55         cputime64_t prev_cpu_idle;
  56         cputime64_t prev_cpu_wall;
  57         struct cpufreq_policy *cur_policy;
  58         struct work_struct work;
  59         unsigned int enable;
  60         struct cpufreq_frequency_table *freq_table;
  61         unsigned int freq_lo;
  62         unsigned int freq_lo_jiffies;
  63         unsigned int freq_hi_jiffies;
  64 };
  65 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
  66
  67 static unsigned int dbs_enable; /* number of CPUs using this policy */
  68
  69 /*
  70  * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
  71  * lock and dbs_mutex. cpu_hotplug lock should always be held before
  72  * dbs_mutex. If any function that can potentially take cpu_hotplug lock
  73  * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
  74  * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
  75  * is recursive for the same process. -Venki
  76  */
  77 static DEFINE_MUTEX(dbs_mutex);
  78
  79 static struct workqueue_struct  *kondemand_wq;
  80
  81 static struct dbs_tuners {
  82         unsigned int sampling_rate;
  83         unsigned int up_threshold;
  84         unsigned int ignore_nice;
  85         unsigned int powersave_bias;
  86 } dbs_tuners_ins = {
  87         .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
  88         .ignore_nice = 0,
  89         .powersave_bias = 0,
  90 };
  91
  92 static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
  93 {
  94         cputime64_t retval;
  95
  96         retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
  97                         kstat_cpu(cpu).cpustat.iowait);
  98
  99         if (dbs_tuners_ins.ignore_nice)
 100                 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
 101
 102         return retval;
 103 }
 104
 105 /*
 106  * Find right freq to be set now with powersave_bias on.
 107  * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
 108  * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
 109  */
 110 static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
 111                                           unsigned int freq_next,
 112                                           unsigned int relation)
 113 {
 114         unsigned int freq_req, freq_reduc, freq_avg;
 115         unsigned int freq_hi, freq_lo;
 116         unsigned int index = 0;
 117         unsigned int jiffies_total, jiffies_hi, jiffies_lo;
 118         struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu);
 119
 120         if (!dbs_info->freq_table) {
 121                 dbs_info->freq_lo = 0;
 122                 dbs_info->freq_lo_jiffies = 0;
 123                 return freq_next;
 124         }
 125
 126         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
 127                         relation, &index);
 128         freq_req = dbs_info->freq_table[index].frequency;
 129         freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000;
 130         freq_avg = freq_req - freq_reduc;
 131
 132         /* Find freq bounds for freq_avg in freq_table */
 133         index = 0;
 134         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
 135                         CPUFREQ_RELATION_H, &index);
 136         freq_lo = dbs_info->freq_table[index].frequency;
 137         index = 0;
 138         cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
 139                         CPUFREQ_RELATION_L, &index);
 140         freq_hi = dbs_info->freq_table[index].frequency;
 141
 142         /* Find out how long we have to be in hi and lo freqs */
 143         if (freq_hi == freq_lo) {
 144                 dbs_info->freq_lo = 0;
 145                 dbs_info->freq_lo_jiffies = 0;
 146                 return freq_lo;
 147         }
 148         jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 149         jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
 150         jiffies_hi += ((freq_hi - freq_lo) / 2);
 151         jiffies_hi /= (freq_hi - freq_lo);
 152         jiffies_lo = jiffies_total - jiffies_hi;
 153         dbs_info->freq_lo = freq_lo;
 154         dbs_info->freq_lo_jiffies = jiffies_lo;
 155         dbs_info->freq_hi_jiffies = jiffies_hi;
 156         return freq_hi;
 157 }
 158
 159 static void ondemand_powersave_bias_init(void)
 160 {
 161         int i;
 162         for_each_online_cpu(i) {
 163                 struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i);
 164                 dbs_info->freq_table = cpufreq_frequency_get_table(i);
 165                 dbs_info->freq_lo = 0;
 166         }
 167 }
 168
 169 /************************** sysfs interface ************************/
 170 static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
 171 {
 172         return sprintf (buf, "%u\n", MAX_SAMPLING_RATE);
 173 }
 174
 175 static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
 176 {
 177         return sprintf (buf, "%u\n", MIN_SAMPLING_RATE);
 178 }
 179
 180 #define define_one_ro(_name)            \
 181 static struct freq_attr _name =         \
 182 __ATTR(_name, 0444, show_##_name, NULL)
 183
 184 define_one_ro(sampling_rate_max);
 185 define_one_ro(sampling_rate_min);
 186
 187 /* cpufreq_ondemand Governor Tunables */
 188 #define show_one(file_name, object)                                     \
 189 static ssize_t show_##file_name                                         \
 190 (struct cpufreq_policy *unused, char *buf)                              \
 191 {                                                                       \
 192         return sprintf(buf, "%u\n", dbs_tuners_ins.object);             \
 193 }
 194 show_one(sampling_rate, sampling_rate);
 195 show_one(up_threshold, up_threshold);
 196 show_one(ignore_nice_load, ignore_nice);
 197 show_one(powersave_bias, powersave_bias);
 198
 199 static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
 200                 const char *buf, size_t count)
 201 {
 202         unsigned int input;
 203         int ret;
 204         ret = sscanf(buf, "%u", &input);
 205
 206         mutex_lock(&dbs_mutex);
 207         if (ret != 1 || input > MAX_SAMPLING_RATE
 208                      || input < MIN_SAMPLING_RATE) {
 209                 mutex_unlock(&dbs_mutex);
 210                 return -EINVAL;
 211         }
 212
 213         dbs_tuners_ins.sampling_rate = input;
 214         mutex_unlock(&dbs_mutex);
 215
 216         return count;
 217 }
 218
 219 static ssize_t store_up_threshold(struct cpufreq_policy *unused,
 220                 const char *buf, size_t count)
 221 {
 222         unsigned int input;
 223         int ret;
 224         ret = sscanf(buf, "%u", &input);
 225
 226         mutex_lock(&dbs_mutex);
 227         if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
 228                         input < MIN_FREQUENCY_UP_THRESHOLD) {
 229                 mutex_unlock(&dbs_mutex);
 230                 return -EINVAL;
 231         }
 232
 233         dbs_tuners_ins.up_threshold = input;
 234         mutex_unlock(&dbs_mutex);
 235
 236         return count;
 237 }
 238
 239 static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
 240                 const char *buf, size_t count)
 241 {
 242         unsigned int input;
 243         int ret;
 244
 245         unsigned int j;
 246
 247         ret = sscanf(buf, "%u", &input);
 248         if ( ret != 1 )
 249                 return -EINVAL;
 250
 251         if ( input > 1 )
 252                 input = 1;
 253
 254         mutex_lock(&dbs_mutex);
 255         if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
 256                 mutex_unlock(&dbs_mutex);
 257                 return count;
 258         }
 259         dbs_tuners_ins.ignore_nice = input;
 260
 261         /* we need to re-evaluate prev_cpu_idle */
 262         for_each_online_cpu(j) {
 263                 struct cpu_dbs_info_s *dbs_info;
 264                 dbs_info = &per_cpu(cpu_dbs_info, j);
 265                 dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
 266                 dbs_info->prev_cpu_wall = get_jiffies_64();
 267         }
 268         mutex_unlock(&dbs_mutex);
 269
 270         return count;
 271 }
 272
 273 static ssize_t store_powersave_bias(struct cpufreq_policy *unused,
 274                 const char *buf, size_t count)
 275 {
 276         unsigned int input;
 277         int ret;
 278         ret = sscanf(buf, "%u", &input);
 279
 280         if (ret != 1)
 281                 return -EINVAL;
 282
 283         if (input > 1000)
 284                 input = 1000;
 285
 286         mutex_lock(&dbs_mutex);
 287         dbs_tuners_ins.powersave_bias = input;
 288         ondemand_powersave_bias_init();
 289         mutex_unlock(&dbs_mutex);
 290
 291         return count;
 292 }
 293
 294 #define define_one_rw(_name) \
 295 static struct freq_attr _name = \
 296 __ATTR(_name, 0644, show_##_name, store_##_name)
 297
 298 define_one_rw(sampling_rate);
 299 define_one_rw(up_threshold);
 300 define_one_rw(ignore_nice_load);
 301 define_one_rw(powersave_bias);
 302
 303 static struct attribute * dbs_attributes[] = {
 304         &sampling_rate_max.attr,
 305         &sampling_rate_min.attr,
 306         &sampling_rate.attr,
 307         &up_threshold.attr,
 308         &ignore_nice_load.attr,
 309         &powersave_bias.attr,
 310         NULL
 311 };
 312
 313 static struct attribute_group dbs_attr_group = {
 314         .attrs = dbs_attributes,
 315         .name = "ondemand",
 316 };
 317
 318 /************************** sysfs end ************************/
 319
 320 static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
 321 {
 322         unsigned int idle_ticks, total_ticks;
 323         unsigned int load;
 324         cputime64_t cur_jiffies;
 325
 326         struct cpufreq_policy *policy;
 327         unsigned int j;
 328
 329         if (!this_dbs_info->enable)
 330                 return;
 331
 332         this_dbs_info->freq_lo = 0;
 333         policy = this_dbs_info->cur_policy;
 334         cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
 335         total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
 336                         this_dbs_info->prev_cpu_wall);
 337         this_dbs_info->prev_cpu_wall = cur_jiffies;
 338         if (!total_ticks)
 339                 return;
 340         /*
 341          * Every sampling_rate, we check, if current idle time is less
 342          * than 20% (default), then we try to increase frequency
 343          * Every sampling_rate, we look for a the lowest
 344          * frequency which can sustain the load while keeping idle time over
 345          * 30%. If such a frequency exist, we try to decrease to this frequency.
 346          *
 347          * Any frequency increase takes it to the maximum frequency.
 348          * Frequency reduction happens at minimum steps of
 349          * 5% (default) of current frequency
 350          */
 351
 352         /* Get Idle Time */
 353         idle_ticks = UINT_MAX;
 354         for_each_cpu_mask(j, policy->cpus) {
 355                 cputime64_t total_idle_ticks;
 356                 unsigned int tmp_idle_ticks;
 357                 struct cpu_dbs_info_s *j_dbs_info;
 358
 359                 j_dbs_info = &per_cpu(cpu_dbs_info, j);
 360                 total_idle_ticks = get_cpu_idle_time(j);
 361                 tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
 362                                 j_dbs_info->prev_cpu_idle);
 363                 j_dbs_info->prev_cpu_idle = total_idle_ticks;
 364
 365                 if (tmp_idle_ticks < idle_ticks)
 366                         idle_ticks = tmp_idle_ticks;
 367         }
 368         load = (100 * (total_ticks - idle_ticks)) / total_ticks;
 369
 370         /* Check for frequency increase */
 371         if (load > dbs_tuners_ins.up_threshold) {
 372                 /* if we are already at full speed then break out early */
 373                 if (!dbs_tuners_ins.powersave_bias) {
 374                         if (policy->cur == policy->max)
 375                                 return;
 376
 377                         __cpufreq_driver_target(policy, policy->max,
 378                                 CPUFREQ_RELATION_H);
 379                 } else {
 380                         int freq = powersave_bias_target(policy, policy->max,
 381                                         CPUFREQ_RELATION_H);
 382                         __cpufreq_driver_target(policy, freq,
 383                                 CPUFREQ_RELATION_L);
 384                 }
 385                 return;
 386         }
 387
 388         /* Check for frequency decrease */
 389         /* if we cannot reduce the frequency anymore, break out early */
 390         if (policy->cur == policy->min)
 391                 return;
 392
 393         /*
 394          * The optimal frequency is the frequency that is the lowest that
 395          * can support the current CPU usage without triggering the up
 396          * policy. To be safe, we focus 10 points under the threshold.
 397          */
 398         if (load < (dbs_tuners_ins.up_threshold - 10)) {
 399                 unsigned int freq_next, freq_cur;
 400
 401                 freq_cur = cpufreq_driver_getavg(policy);
 402                 if (!freq_cur)
 403                         freq_cur = policy->cur;
 404
 405                 freq_next = (freq_cur * load) /
 406                         (dbs_tuners_ins.up_threshold - 10);
 407
 408                 if (!dbs_tuners_ins.powersave_bias) {
 409                         __cpufreq_driver_target(policy, freq_next,
 410                                         CPUFREQ_RELATION_L);
 411                 } else {
 412                         int freq = powersave_bias_target(policy, freq_next,
 413                                         CPUFREQ_RELATION_L);
 414                         __cpufreq_driver_target(policy, freq,
 415                                 CPUFREQ_RELATION_L);
 416                 }
 417         }
 418 }
 419
 420 /* Sampling types */
 421 enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
 422
 423 static void do_dbs_timer(void *data)
 424 {
 425         unsigned int cpu = smp_processor_id();
 426         struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
 427         /* We want all CPUs to do sampling nearly on same jiffy */
 428         int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 429         delay -= jiffies % delay;
 430
 431         if (!dbs_info->enable)
 432                 return;
 433         /* Common NORMAL_SAMPLE setup */
 434         INIT_WORK(&dbs_info->work, do_dbs_timer, (void *)DBS_NORMAL_SAMPLE);
 435         if (!dbs_tuners_ins.powersave_bias ||
 436             (unsigned long) data == DBS_NORMAL_SAMPLE) {
 437                 lock_cpu_hotplug();
 438                 dbs_check_cpu(dbs_info);
 439                 unlock_cpu_hotplug();
 440                 if (dbs_info->freq_lo) {
 441                         /* Setup timer for SUB_SAMPLE */
 442                         INIT_WORK(&dbs_info->work, do_dbs_timer,
 443                                         (void *)DBS_SUB_SAMPLE);
 444                         delay = dbs_info->freq_hi_jiffies;
 445                 }
 446         } else {
 447                 __cpufreq_driver_target(dbs_info->cur_policy,
 448                                         dbs_info->freq_lo,
 449                                         CPUFREQ_RELATION_H);
 450         }
 451         queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
 452 }
 453
 454 static inline void dbs_timer_init(unsigned int cpu)
 455 {
 456         struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
 457         /* We want all CPUs to do sampling nearly on same jiffy */
 458         int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
 459         delay -= jiffies % delay;
 460
 461         ondemand_powersave_bias_init();
 462         INIT_WORK(&dbs_info->work, do_dbs_timer, NULL);
 463         queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
 464 }
 465
 466 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
 467 {
 468         dbs_info->enable = 0;
 469         cancel_delayed_work(&dbs_info->work);
 470         flush_workqueue(kondemand_wq);
 471 }
 472
 473 static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 474                                    unsigned int event)
 475 {
 476         unsigned int cpu = policy->cpu;
 477         struct cpu_dbs_info_s *this_dbs_info;
 478         unsigned int j;
 479         int rc;
 480
 481         this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
 482
 483         switch (event) {
 484         case CPUFREQ_GOV_START:
 485                 if ((!cpu_online(cpu)) || (!policy->cur))
 486                         return -EINVAL;
 487
 488                 if (policy->cpuinfo.transition_latency >
 489                                 (TRANSITION_LATENCY_LIMIT * 1000)) {
 490                         printk(KERN_WARNING "ondemand governor failed to load "
 491                                "due to too long transition latency\n");
 492                         return -EINVAL;
 493                 }
 494                 if (this_dbs_info->enable) /* Already enabled */
 495                         break;
 496
 497                 mutex_lock(&dbs_mutex);
 498                 dbs_enable++;
 499                 if (dbs_enable == 1) {
 500                         kondemand_wq = create_workqueue("kondemand");
 501                         if (!kondemand_wq) {
 502                                 printk(KERN_ERR
 503                                          "Creation of kondemand failed\n");
 504                                 dbs_enable--;
 505                                 mutex_unlock(&dbs_mutex);
 506                                 return -ENOSPC;
 507                         }
 508                 }
 509
 510                 rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
 511                 if (rc) {
 512                         if (dbs_enable == 1)
 513                                 destroy_workqueue(kondemand_wq);
 514                         dbs_enable--;
 515                         mutex_unlock(&dbs_mutex);
 516                         return rc;
 517                 }
 518
 519                 for_each_cpu_mask(j, policy->cpus) {
 520                         struct cpu_dbs_info_s *j_dbs_info;
 521                         j_dbs_info = &per_cpu(cpu_dbs_info, j);
 522                         j_dbs_info->cur_policy = policy;
 523
 524                         j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
 525                         j_dbs_info->prev_cpu_wall = get_jiffies_64();
 526                 }
 527                 this_dbs_info->enable = 1;
 528                 /*
 529                  * Start the timerschedule work, when this governor
 530                  * is used for first time
 531                  */
 532                 if (dbs_enable == 1) {
 533                         unsigned int latency;
 534                         /* policy latency is in nS. Convert it to uS first */
 535                         latency = policy->cpuinfo.transition_latency / 1000;
 536                         if (latency == 0)
 537                                 latency = 1;
 538
 539                         def_sampling_rate = latency *
 540                                         DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
 541
 542                         if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
 543                                 def_sampling_rate = MIN_STAT_SAMPLING_RATE;
 544
 545                         dbs_tuners_ins.sampling_rate = def_sampling_rate;
 546                 }
 547                 dbs_timer_init(policy->cpu);
 548
 549                 mutex_unlock(&dbs_mutex);
 550                 break;
 551
 552         case CPUFREQ_GOV_STOP:
 553                 mutex_lock(&dbs_mutex);
 554                 dbs_timer_exit(this_dbs_info);
 555                 sysfs_remove_group(&policy->kobj, &dbs_attr_group);
 556                 dbs_enable--;
 557                 if (dbs_enable == 0)
 558                         destroy_workqueue(kondemand_wq);
 559
 560                 mutex_unlock(&dbs_mutex);
 561
 562                 break;
 563
 564         case CPUFREQ_GOV_LIMITS:
 565                 mutex_lock(&dbs_mutex);
 566                 if (policy->max < this_dbs_info->cur_policy->cur)
 567                         __cpufreq_driver_target(this_dbs_info->cur_policy,
 568                                                 policy->max,
 569                                                 CPUFREQ_RELATION_H);
 570                 else if (policy->min > this_dbs_info->cur_policy->cur)
 571                         __cpufreq_driver_target(this_dbs_info->cur_policy,
 572                                                 policy->min,
 573                                                 CPUFREQ_RELATION_L);
 574                 mutex_unlock(&dbs_mutex);
 575                 break;
 576         }
 577         return 0;
 578 }
 579
 580 static struct cpufreq_governor cpufreq_gov_dbs = {
 581         .name = "ondemand",
 582         .governor = cpufreq_governor_dbs,
 583         .owner = THIS_MODULE,
 584 };
 585
 586 static int __init cpufreq_gov_dbs_init(void)
 587 {
 588         return cpufreq_register_governor(&cpufreq_gov_dbs);
 589 }
 590
 591 static void __exit cpufreq_gov_dbs_exit(void)
 592 {
 593         cpufreq_unregister_governor(&cpufreq_gov_dbs);
 594 }
 595
 596
 597 MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
 598 MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
 599 MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
 600                    "Low Latency Frequency Transition capable processors");
 601 MODULE_LICENSE("GPL");
 602
 603 module_init(cpufreq_gov_dbs_init);
 604 module_exit(cpufreq_gov_dbs_exit);