1 /* 2 * drivers/cpufreq/cpufreq_conservative.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 * (C) 2009 Alexander Clouter <alex@digriz.org.uk> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/cpufreq.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/kernel_stat.h> 18 #include <linux/kobject.h> 19 #include <linux/module.h> 20 #include <linux/mutex.h> 21 #include <linux/notifier.h> 22 #include <linux/percpu-defs.h> 23 #include <linux/slab.h> 24 #include <linux/sysfs.h> 25 #include <linux/types.h> 26 27 #include "cpufreq_governor.h" 28 29 /* Conservative governor macros */ 30 #define DEF_FREQUENCY_UP_THRESHOLD (80) 31 #define DEF_FREQUENCY_DOWN_THRESHOLD (20) 32 #define DEF_SAMPLING_DOWN_FACTOR (1) 33 #define MAX_SAMPLING_DOWN_FACTOR (10) 34 35 static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); 36 37 /* 38 * Every sampling_rate, we check, if current idle time is less than 20% 39 * (default), then we try to increase frequency. Every sampling_rate * 40 * sampling_down_factor, we check, if current idle time is more than 80% 41 * (default), then we try to decrease frequency 42 * 43 * Any frequency increase takes it to the maximum frequency. Frequency reduction 44 * happens at minimum steps of 5% (default) of maximum frequency 45 */ 46 static void cs_check_cpu(int cpu, unsigned int load) 47 { 48 struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); 49 struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy; 50 struct dbs_data *dbs_data = policy->governor_data; 51 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 52 unsigned int freq_target; 53 54 /* 55 * break out if we 'cannot' reduce the speed as the user might 56 * want freq_step to be zero 57 */ 58 if (cs_tuners->freq_step == 0) 59 return; 60 61 /* Check for frequency increase */ 62 if (load > cs_tuners->up_threshold) { 63 dbs_info->down_skip = 0; 64 65 /* if we are already at full speed then break out early */ 66 if (dbs_info->requested_freq == policy->max) 67 return; 68 69 freq_target = (cs_tuners->freq_step * policy->max) / 100; 70 71 /* max freq cannot be less than 100. But who knows.... */ 72 if (unlikely(freq_target == 0)) 73 freq_target = 5; 74 75 dbs_info->requested_freq += freq_target; 76 if (dbs_info->requested_freq > policy->max) 77 dbs_info->requested_freq = policy->max; 78 79 __cpufreq_driver_target(policy, dbs_info->requested_freq, 80 CPUFREQ_RELATION_H); 81 return; 82 } 83 84 /* if sampling_down_factor is active break out early */ 85 if (++dbs_info->down_skip < cs_tuners->sampling_down_factor) 86 return; 87 dbs_info->down_skip = 0; 88 89 /* Check for frequency decrease */ 90 if (load < cs_tuners->down_threshold) { 91 /* 92 * if we cannot reduce the frequency anymore, break out early 93 */ 94 if (policy->cur == policy->min) 95 return; 96 97 freq_target = (cs_tuners->freq_step * policy->max) / 100; 98 99 dbs_info->requested_freq -= freq_target; 100 if (dbs_info->requested_freq < policy->min) 101 dbs_info->requested_freq = policy->min; 102 103 __cpufreq_driver_target(policy, dbs_info->requested_freq, 104 CPUFREQ_RELATION_L); 105 return; 106 } 107 } 108 109 static void cs_dbs_timer(struct work_struct *work) 110 { 111 struct cs_cpu_dbs_info_s *dbs_info = container_of(work, 112 struct cs_cpu_dbs_info_s, cdbs.work.work); 113 unsigned int cpu = dbs_info->cdbs.cur_policy->cpu; 114 struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info, 115 cpu); 116 struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data; 117 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 118 int delay = delay_for_sampling_rate(cs_tuners->sampling_rate); 119 bool modify_all = true; 120 121 mutex_lock(&core_dbs_info->cdbs.timer_mutex); 122 if (!need_load_eval(&core_dbs_info->cdbs, cs_tuners->sampling_rate)) 123 modify_all = false; 124 else 125 dbs_check_cpu(dbs_data, cpu); 126 127 gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all); 128 mutex_unlock(&core_dbs_info->cdbs.timer_mutex); 129 } 130 131 static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, 132 void *data) 133 { 134 struct cpufreq_freqs *freq = data; 135 struct cs_cpu_dbs_info_s *dbs_info = 136 &per_cpu(cs_cpu_dbs_info, freq->cpu); 137 struct cpufreq_policy *policy; 138 139 if (!dbs_info->enable) 140 return 0; 141 142 policy = dbs_info->cdbs.cur_policy; 143 144 /* 145 * we only care if our internally tracked freq moves outside the 'valid' 146 * ranges of frequency available to us otherwise we do not change it 147 */ 148 if (dbs_info->requested_freq > policy->max 149 || dbs_info->requested_freq < policy->min) 150 dbs_info->requested_freq = freq->new; 151 152 return 0; 153 } 154 155 /************************** sysfs interface ************************/ 156 static struct common_dbs_data cs_dbs_cdata; 157 158 static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, 159 const char *buf, size_t count) 160 { 161 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 162 unsigned int input; 163 int ret; 164 ret = sscanf(buf, "%u", &input); 165 166 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) 167 return -EINVAL; 168 169 cs_tuners->sampling_down_factor = input; 170 return count; 171 } 172 173 static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf, 174 size_t count) 175 { 176 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 177 unsigned int input; 178 int ret; 179 ret = sscanf(buf, "%u", &input); 180 181 if (ret != 1) 182 return -EINVAL; 183 184 cs_tuners->sampling_rate = max(input, dbs_data->min_sampling_rate); 185 return count; 186 } 187 188 static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf, 189 size_t count) 190 { 191 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 192 unsigned int input; 193 int ret; 194 ret = sscanf(buf, "%u", &input); 195 196 if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) 197 return -EINVAL; 198 199 cs_tuners->up_threshold = input; 200 return count; 201 } 202 203 static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf, 204 size_t count) 205 { 206 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 207 unsigned int input; 208 int ret; 209 ret = sscanf(buf, "%u", &input); 210 211 /* cannot be lower than 11 otherwise freq will not fall */ 212 if (ret != 1 || input < 11 || input > 100 || 213 input >= cs_tuners->up_threshold) 214 return -EINVAL; 215 216 cs_tuners->down_threshold = input; 217 return count; 218 } 219 220 static ssize_t store_ignore_nice(struct dbs_data *dbs_data, const char *buf, 221 size_t count) 222 { 223 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 224 unsigned int input, j; 225 int ret; 226 227 ret = sscanf(buf, "%u", &input); 228 if (ret != 1) 229 return -EINVAL; 230 231 if (input > 1) 232 input = 1; 233 234 if (input == cs_tuners->ignore_nice) /* nothing to do */ 235 return count; 236 237 cs_tuners->ignore_nice = input; 238 239 /* we need to re-evaluate prev_cpu_idle */ 240 for_each_online_cpu(j) { 241 struct cs_cpu_dbs_info_s *dbs_info; 242 dbs_info = &per_cpu(cs_cpu_dbs_info, j); 243 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j, 244 &dbs_info->cdbs.prev_cpu_wall, 0); 245 if (cs_tuners->ignore_nice) 246 dbs_info->cdbs.prev_cpu_nice = 247 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 248 } 249 return count; 250 } 251 252 static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf, 253 size_t count) 254 { 255 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 256 unsigned int input; 257 int ret; 258 ret = sscanf(buf, "%u", &input); 259 260 if (ret != 1) 261 return -EINVAL; 262 263 if (input > 100) 264 input = 100; 265 266 /* 267 * no need to test here if freq_step is zero as the user might actually 268 * want this, they would be crazy though :) 269 */ 270 cs_tuners->freq_step = input; 271 return count; 272 } 273 274 show_store_one(cs, sampling_rate); 275 show_store_one(cs, sampling_down_factor); 276 show_store_one(cs, up_threshold); 277 show_store_one(cs, down_threshold); 278 show_store_one(cs, ignore_nice); 279 show_store_one(cs, freq_step); 280 declare_show_sampling_rate_min(cs); 281 282 gov_sys_pol_attr_rw(sampling_rate); 283 gov_sys_pol_attr_rw(sampling_down_factor); 284 gov_sys_pol_attr_rw(up_threshold); 285 gov_sys_pol_attr_rw(down_threshold); 286 gov_sys_pol_attr_rw(ignore_nice); 287 gov_sys_pol_attr_rw(freq_step); 288 gov_sys_pol_attr_ro(sampling_rate_min); 289 290 static struct attribute *dbs_attributes_gov_sys[] = { 291 &sampling_rate_min_gov_sys.attr, 292 &sampling_rate_gov_sys.attr, 293 &sampling_down_factor_gov_sys.attr, 294 &up_threshold_gov_sys.attr, 295 &down_threshold_gov_sys.attr, 296 &ignore_nice_gov_sys.attr, 297 &freq_step_gov_sys.attr, 298 NULL 299 }; 300 301 static struct attribute_group cs_attr_group_gov_sys = { 302 .attrs = dbs_attributes_gov_sys, 303 .name = "conservative", 304 }; 305 306 static struct attribute *dbs_attributes_gov_pol[] = { 307 &sampling_rate_min_gov_pol.attr, 308 &sampling_rate_gov_pol.attr, 309 &sampling_down_factor_gov_pol.attr, 310 &up_threshold_gov_pol.attr, 311 &down_threshold_gov_pol.attr, 312 &ignore_nice_gov_pol.attr, 313 &freq_step_gov_pol.attr, 314 NULL 315 }; 316 317 static struct attribute_group cs_attr_group_gov_pol = { 318 .attrs = dbs_attributes_gov_pol, 319 .name = "conservative", 320 }; 321 322 /************************** sysfs end ************************/ 323 324 static int cs_init(struct dbs_data *dbs_data) 325 { 326 struct cs_dbs_tuners *tuners; 327 328 tuners = kzalloc(sizeof(struct cs_dbs_tuners), GFP_KERNEL); 329 if (!tuners) { 330 pr_err("%s: kzalloc failed\n", __func__); 331 return -ENOMEM; 332 } 333 334 tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; 335 tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; 336 tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; 337 tuners->ignore_nice = 0; 338 tuners->freq_step = 5; 339 340 dbs_data->tuners = tuners; 341 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * 342 jiffies_to_usecs(10); 343 mutex_init(&dbs_data->mutex); 344 return 0; 345 } 346 347 static void cs_exit(struct dbs_data *dbs_data) 348 { 349 kfree(dbs_data->tuners); 350 } 351 352 define_get_cpu_dbs_routines(cs_cpu_dbs_info); 353 354 static struct notifier_block cs_cpufreq_notifier_block = { 355 .notifier_call = dbs_cpufreq_notifier, 356 }; 357 358 static struct cs_ops cs_ops = { 359 .notifier_block = &cs_cpufreq_notifier_block, 360 }; 361 362 static struct common_dbs_data cs_dbs_cdata = { 363 .governor = GOV_CONSERVATIVE, 364 .attr_group_gov_sys = &cs_attr_group_gov_sys, 365 .attr_group_gov_pol = &cs_attr_group_gov_pol, 366 .get_cpu_cdbs = get_cpu_cdbs, 367 .get_cpu_dbs_info_s = get_cpu_dbs_info_s, 368 .gov_dbs_timer = cs_dbs_timer, 369 .gov_check_cpu = cs_check_cpu, 370 .gov_ops = &cs_ops, 371 .init = cs_init, 372 .exit = cs_exit, 373 }; 374 375 static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, 376 unsigned int event) 377 { 378 return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event); 379 } 380 381 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 382 static 383 #endif 384 struct cpufreq_governor cpufreq_gov_conservative = { 385 .name = "conservative", 386 .governor = cs_cpufreq_governor_dbs, 387 .max_transition_latency = TRANSITION_LATENCY_LIMIT, 388 .owner = THIS_MODULE, 389 }; 390 391 static int __init cpufreq_gov_dbs_init(void) 392 { 393 return cpufreq_register_governor(&cpufreq_gov_conservative); 394 } 395 396 static void __exit cpufreq_gov_dbs_exit(void) 397 { 398 cpufreq_unregister_governor(&cpufreq_gov_conservative); 399 } 400 401 MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); 402 MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " 403 "Low Latency Frequency Transition capable processors " 404 "optimised for use in a battery environment"); 405 MODULE_LICENSE("GPL"); 406 407 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 408 fs_initcall(cpufreq_gov_dbs_init); 409 #else 410 module_init(cpufreq_gov_dbs_init); 411 #endif 412 module_exit(cpufreq_gov_dbs_exit); 413