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