Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/smp.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/ctype.h> |
| 19 | #include <linux/cpufreq.h> |
| 20 | #include <linux/sysctl.h> |
| 21 | #include <linux/types.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/sysfs.h> |
| 24 | #include <linux/sched.h> |
| 25 | #include <linux/kmod.h> |
| 26 | #include <linux/workqueue.h> |
| 27 | #include <linux/jiffies.h> |
| 28 | #include <linux/kernel_stat.h> |
| 29 | #include <linux/percpu.h> |
| 30 | |
| 31 | /* |
| 32 | * dbs is used in this file as a shortform for demandbased switching |
| 33 | * It helps to keep variable names smaller, simpler |
| 34 | */ |
| 35 | |
| 36 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 37 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
| 39 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | /* |
| 41 | * The polling frequency of this governor depends on the capability of |
| 42 | * the processor. Default polling frequency is 1000 times the transition |
| 43 | * latency of the processor. The governor will work on any processor with |
| 44 | * transition latency <= 10mS, using appropriate sampling |
| 45 | * rate. |
| 46 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) |
| 47 | * this governor will not work. |
| 48 | * All times here are in uS. |
| 49 | */ |
| 50 | static unsigned int def_sampling_rate; |
| 51 | #define MIN_SAMPLING_RATE (def_sampling_rate / 2) |
| 52 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
| 53 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
Dave Jones | e131832 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 54 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
| 55 | #define MAX_SAMPLING_DOWN_FACTOR (10) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | |
| 58 | static void do_dbs_timer(void *data); |
| 59 | |
| 60 | struct cpu_dbs_info_s { |
| 61 | struct cpufreq_policy *cur_policy; |
| 62 | unsigned int prev_cpu_idle_up; |
| 63 | unsigned int prev_cpu_idle_down; |
| 64 | unsigned int enable; |
| 65 | }; |
| 66 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); |
| 67 | |
| 68 | static unsigned int dbs_enable; /* number of CPUs using this policy */ |
| 69 | |
| 70 | static DECLARE_MUTEX (dbs_sem); |
| 71 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
| 72 | |
| 73 | struct dbs_tuners { |
| 74 | unsigned int sampling_rate; |
| 75 | unsigned int sampling_down_factor; |
| 76 | unsigned int up_threshold; |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 77 | unsigned int ignore_nice; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | }; |
| 79 | |
| 80 | static struct dbs_tuners dbs_tuners_ins = { |
| 81 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, |
| 83 | }; |
| 84 | |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 85 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
| 86 | { |
| 87 | return kstat_cpu(cpu).cpustat.idle + |
| 88 | kstat_cpu(cpu).cpustat.iowait + |
| 89 | ( !dbs_tuners_ins.ignore_nice ? |
| 90 | kstat_cpu(cpu).cpustat.nice : |
| 91 | 0); |
| 92 | } |
| 93 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | /************************** sysfs interface ************************/ |
| 95 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) |
| 96 | { |
| 97 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); |
| 98 | } |
| 99 | |
| 100 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) |
| 101 | { |
| 102 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); |
| 103 | } |
| 104 | |
| 105 | #define define_one_ro(_name) \ |
| 106 | static struct freq_attr _name = \ |
| 107 | __ATTR(_name, 0444, show_##_name, NULL) |
| 108 | |
| 109 | define_one_ro(sampling_rate_max); |
| 110 | define_one_ro(sampling_rate_min); |
| 111 | |
| 112 | /* cpufreq_ondemand Governor Tunables */ |
| 113 | #define show_one(file_name, object) \ |
| 114 | static ssize_t show_##file_name \ |
| 115 | (struct cpufreq_policy *unused, char *buf) \ |
| 116 | { \ |
| 117 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ |
| 118 | } |
| 119 | show_one(sampling_rate, sampling_rate); |
| 120 | show_one(sampling_down_factor, sampling_down_factor); |
| 121 | show_one(up_threshold, up_threshold); |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 122 | show_one(ignore_nice, ignore_nice); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | |
| 124 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
| 125 | const char *buf, size_t count) |
| 126 | { |
| 127 | unsigned int input; |
| 128 | int ret; |
| 129 | ret = sscanf (buf, "%u", &input); |
| 130 | if (ret != 1 ) |
| 131 | return -EINVAL; |
| 132 | |
Dave Jones | e131832 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 133 | if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
| 134 | return -EINVAL; |
| 135 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | down(&dbs_sem); |
| 137 | dbs_tuners_ins.sampling_down_factor = input; |
| 138 | up(&dbs_sem); |
| 139 | |
| 140 | return count; |
| 141 | } |
| 142 | |
| 143 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
| 144 | const char *buf, size_t count) |
| 145 | { |
| 146 | unsigned int input; |
| 147 | int ret; |
| 148 | ret = sscanf (buf, "%u", &input); |
| 149 | |
| 150 | down(&dbs_sem); |
| 151 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
| 152 | up(&dbs_sem); |
| 153 | return -EINVAL; |
| 154 | } |
| 155 | |
| 156 | dbs_tuners_ins.sampling_rate = input; |
| 157 | up(&dbs_sem); |
| 158 | |
| 159 | return count; |
| 160 | } |
| 161 | |
| 162 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
| 163 | const char *buf, size_t count) |
| 164 | { |
| 165 | unsigned int input; |
| 166 | int ret; |
| 167 | ret = sscanf (buf, "%u", &input); |
| 168 | |
| 169 | down(&dbs_sem); |
| 170 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 171 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | up(&dbs_sem); |
| 173 | return -EINVAL; |
| 174 | } |
| 175 | |
| 176 | dbs_tuners_ins.up_threshold = input; |
| 177 | up(&dbs_sem); |
| 178 | |
| 179 | return count; |
| 180 | } |
| 181 | |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 182 | static ssize_t store_ignore_nice(struct cpufreq_policy *policy, |
| 183 | const char *buf, size_t count) |
| 184 | { |
| 185 | unsigned int input; |
| 186 | int ret; |
| 187 | |
| 188 | unsigned int j; |
| 189 | |
| 190 | ret = sscanf (buf, "%u", &input); |
| 191 | if ( ret != 1 ) |
| 192 | return -EINVAL; |
| 193 | |
| 194 | if ( input > 1 ) |
| 195 | input = 1; |
| 196 | |
| 197 | down(&dbs_sem); |
| 198 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
| 199 | up(&dbs_sem); |
| 200 | return count; |
| 201 | } |
| 202 | dbs_tuners_ins.ignore_nice = input; |
| 203 | |
| 204 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 205 | for_each_online_cpu(j) { |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 206 | struct cpu_dbs_info_s *j_dbs_info; |
| 207 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 208 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 209 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
| 210 | } |
| 211 | up(&dbs_sem); |
| 212 | |
| 213 | return count; |
| 214 | } |
| 215 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | #define define_one_rw(_name) \ |
| 217 | static struct freq_attr _name = \ |
| 218 | __ATTR(_name, 0644, show_##_name, store_##_name) |
| 219 | |
| 220 | define_one_rw(sampling_rate); |
| 221 | define_one_rw(sampling_down_factor); |
| 222 | define_one_rw(up_threshold); |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 223 | define_one_rw(ignore_nice); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | |
| 225 | static struct attribute * dbs_attributes[] = { |
| 226 | &sampling_rate_max.attr, |
| 227 | &sampling_rate_min.attr, |
| 228 | &sampling_rate.attr, |
| 229 | &sampling_down_factor.attr, |
| 230 | &up_threshold.attr, |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 231 | &ignore_nice.attr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | NULL |
| 233 | }; |
| 234 | |
| 235 | static struct attribute_group dbs_attr_group = { |
| 236 | .attrs = dbs_attributes, |
| 237 | .name = "ondemand", |
| 238 | }; |
| 239 | |
| 240 | /************************** sysfs end ************************/ |
| 241 | |
| 242 | static void dbs_check_cpu(int cpu) |
| 243 | { |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 244 | unsigned int idle_ticks, up_idle_ticks, total_ticks; |
| 245 | unsigned int freq_next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | unsigned int freq_down_sampling_rate; |
| 247 | static int down_skip[NR_CPUS]; |
| 248 | struct cpu_dbs_info_s *this_dbs_info; |
| 249 | |
| 250 | struct cpufreq_policy *policy; |
| 251 | unsigned int j; |
| 252 | |
| 253 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 254 | if (!this_dbs_info->enable) |
| 255 | return; |
| 256 | |
| 257 | policy = this_dbs_info->cur_policy; |
| 258 | /* |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 259 | * Every sampling_rate, we check, if current idle time is less |
| 260 | * than 20% (default), then we try to increase frequency |
| 261 | * Every sampling_rate*sampling_down_factor, we look for a the lowest |
| 262 | * frequency which can sustain the load while keeping idle time over |
| 263 | * 30%. If such a frequency exist, we try to decrease to this frequency. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | * |
| 265 | * Any frequency increase takes it to the maximum frequency. |
| 266 | * Frequency reduction happens at minimum steps of |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 267 | * 5% (default) of current frequency |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 268 | */ |
| 269 | |
| 270 | /* Check for frequency increase */ |
Dave Jones | 9c7d269 | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 271 | idle_ticks = UINT_MAX; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | for_each_cpu_mask(j, policy->cpus) { |
Dave Jones | 9c7d269 | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 273 | unsigned int tmp_idle_ticks, total_idle_ticks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | struct cpu_dbs_info_s *j_dbs_info; |
| 275 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 277 | total_idle_ticks = get_cpu_idle_time(j); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | tmp_idle_ticks = total_idle_ticks - |
| 279 | j_dbs_info->prev_cpu_idle_up; |
| 280 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; |
| 281 | |
| 282 | if (tmp_idle_ticks < idle_ticks) |
| 283 | idle_ticks = tmp_idle_ticks; |
| 284 | } |
| 285 | |
| 286 | /* Scale idle ticks by 100 and compare with up and down ticks */ |
| 287 | idle_ticks *= 100; |
| 288 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * |
Dave Jones | 6fe7116 | 2005-05-31 19:03:44 -0700 | [diff] [blame] | 289 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | |
| 291 | if (idle_ticks < up_idle_ticks) { |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 292 | down_skip[cpu] = 0; |
Dave Jones | 790d76f | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 293 | for_each_cpu_mask(j, policy->cpus) { |
| 294 | struct cpu_dbs_info_s *j_dbs_info; |
| 295 | |
| 296 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 297 | j_dbs_info->prev_cpu_idle_down = |
| 298 | j_dbs_info->prev_cpu_idle_up; |
| 299 | } |
Dave Jones | c11420a | 2005-05-31 19:03:48 -0700 | [diff] [blame] | 300 | /* if we are already at full speed then break out early */ |
| 301 | if (policy->cur == policy->max) |
| 302 | return; |
| 303 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | __cpufreq_driver_target(policy, policy->max, |
| 305 | CPUFREQ_RELATION_H); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | return; |
| 307 | } |
| 308 | |
| 309 | /* Check for frequency decrease */ |
| 310 | down_skip[cpu]++; |
| 311 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) |
| 312 | return; |
| 313 | |
Dave Jones | 9c7d269 | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 314 | idle_ticks = UINT_MAX; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | for_each_cpu_mask(j, policy->cpus) { |
Dave Jones | 9c7d269 | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 316 | unsigned int tmp_idle_ticks, total_idle_ticks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | struct cpu_dbs_info_s *j_dbs_info; |
| 318 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 320 | /* Check for frequency decrease */ |
| 321 | total_idle_ticks = j_dbs_info->prev_cpu_idle_up; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | tmp_idle_ticks = total_idle_ticks - |
| 323 | j_dbs_info->prev_cpu_idle_down; |
| 324 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; |
| 325 | |
| 326 | if (tmp_idle_ticks < idle_ticks) |
| 327 | idle_ticks = tmp_idle_ticks; |
| 328 | } |
| 329 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 330 | down_skip[cpu] = 0; |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 331 | /* if we cannot reduce the frequency anymore, break out early */ |
| 332 | if (policy->cur == policy->min) |
| 333 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 335 | /* Compute how many ticks there are between two measurements */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * |
| 337 | dbs_tuners_ins.sampling_down_factor; |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 338 | total_ticks = usecs_to_jiffies(freq_down_sampling_rate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 340 | /* |
| 341 | * The optimal frequency is the frequency that is the lowest that |
| 342 | * can support the current CPU usage without triggering the up |
| 343 | * policy. To be safe, we focus 10 points under the threshold. |
| 344 | */ |
| 345 | freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; |
| 346 | freq_next = (freq_next * policy->cur) / |
| 347 | (dbs_tuners_ins.up_threshold - 10); |
Dave Jones | 1206aaa | 2005-05-31 19:03:48 -0700 | [diff] [blame] | 348 | |
Dave Jones | c29f140 | 2005-05-31 19:03:50 -0700 | [diff] [blame] | 349 | if (freq_next <= ((policy->cur * 95) / 100)) |
| 350 | __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | } |
| 352 | |
| 353 | static void do_dbs_timer(void *data) |
| 354 | { |
| 355 | int i; |
| 356 | down(&dbs_sem); |
Dave Jones | 6fe7116 | 2005-05-31 19:03:44 -0700 | [diff] [blame] | 357 | for_each_online_cpu(i) |
| 358 | dbs_check_cpu(i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | schedule_delayed_work(&dbs_work, |
Dave Jones | 6fe7116 | 2005-05-31 19:03:44 -0700 | [diff] [blame] | 360 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | up(&dbs_sem); |
| 362 | } |
| 363 | |
| 364 | static inline void dbs_timer_init(void) |
| 365 | { |
| 366 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); |
| 367 | schedule_delayed_work(&dbs_work, |
Dave Jones | 6fe7116 | 2005-05-31 19:03:44 -0700 | [diff] [blame] | 368 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | return; |
| 370 | } |
| 371 | |
| 372 | static inline void dbs_timer_exit(void) |
| 373 | { |
| 374 | cancel_delayed_work(&dbs_work); |
| 375 | return; |
| 376 | } |
| 377 | |
| 378 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| 379 | unsigned int event) |
| 380 | { |
| 381 | unsigned int cpu = policy->cpu; |
| 382 | struct cpu_dbs_info_s *this_dbs_info; |
| 383 | unsigned int j; |
| 384 | |
| 385 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 386 | |
| 387 | switch (event) { |
| 388 | case CPUFREQ_GOV_START: |
| 389 | if ((!cpu_online(cpu)) || |
| 390 | (!policy->cur)) |
| 391 | return -EINVAL; |
| 392 | |
| 393 | if (policy->cpuinfo.transition_latency > |
| 394 | (TRANSITION_LATENCY_LIMIT * 1000)) |
| 395 | return -EINVAL; |
| 396 | if (this_dbs_info->enable) /* Already enabled */ |
| 397 | break; |
| 398 | |
| 399 | down(&dbs_sem); |
| 400 | for_each_cpu_mask(j, policy->cpus) { |
| 401 | struct cpu_dbs_info_s *j_dbs_info; |
| 402 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 403 | j_dbs_info->cur_policy = policy; |
| 404 | |
Dave Jones | dac1c1a | 2005-05-31 19:03:49 -0700 | [diff] [blame] | 405 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 406 | j_dbs_info->prev_cpu_idle_down |
| 407 | = j_dbs_info->prev_cpu_idle_up; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | } |
| 409 | this_dbs_info->enable = 1; |
| 410 | sysfs_create_group(&policy->kobj, &dbs_attr_group); |
| 411 | dbs_enable++; |
| 412 | /* |
| 413 | * Start the timerschedule work, when this governor |
| 414 | * is used for first time |
| 415 | */ |
| 416 | if (dbs_enable == 1) { |
| 417 | unsigned int latency; |
| 418 | /* policy latency is in nS. Convert it to uS first */ |
| 419 | |
| 420 | latency = policy->cpuinfo.transition_latency; |
| 421 | if (latency < 1000) |
| 422 | latency = 1000; |
| 423 | |
| 424 | def_sampling_rate = (latency / 1000) * |
| 425 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
| 426 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
Dave Jones | 3d5ee9e | 2005-05-31 19:03:47 -0700 | [diff] [blame] | 427 | dbs_tuners_ins.ignore_nice = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | |
| 429 | dbs_timer_init(); |
| 430 | } |
| 431 | |
| 432 | up(&dbs_sem); |
| 433 | break; |
| 434 | |
| 435 | case CPUFREQ_GOV_STOP: |
| 436 | down(&dbs_sem); |
| 437 | this_dbs_info->enable = 0; |
| 438 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
| 439 | dbs_enable--; |
| 440 | /* |
| 441 | * Stop the timerschedule work, when this governor |
| 442 | * is used for first time |
| 443 | */ |
| 444 | if (dbs_enable == 0) |
| 445 | dbs_timer_exit(); |
| 446 | |
| 447 | up(&dbs_sem); |
| 448 | |
| 449 | break; |
| 450 | |
| 451 | case CPUFREQ_GOV_LIMITS: |
| 452 | down(&dbs_sem); |
| 453 | if (policy->max < this_dbs_info->cur_policy->cur) |
| 454 | __cpufreq_driver_target( |
| 455 | this_dbs_info->cur_policy, |
| 456 | policy->max, CPUFREQ_RELATION_H); |
| 457 | else if (policy->min > this_dbs_info->cur_policy->cur) |
| 458 | __cpufreq_driver_target( |
| 459 | this_dbs_info->cur_policy, |
| 460 | policy->min, CPUFREQ_RELATION_L); |
| 461 | up(&dbs_sem); |
| 462 | break; |
| 463 | } |
| 464 | return 0; |
| 465 | } |
| 466 | |
Dave Jones | 7f335d4 | 2005-05-31 19:03:46 -0700 | [diff] [blame] | 467 | static struct cpufreq_governor cpufreq_gov_dbs = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | .name = "ondemand", |
| 469 | .governor = cpufreq_governor_dbs, |
| 470 | .owner = THIS_MODULE, |
| 471 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | |
| 473 | static int __init cpufreq_gov_dbs_init(void) |
| 474 | { |
| 475 | return cpufreq_register_governor(&cpufreq_gov_dbs); |
| 476 | } |
| 477 | |
| 478 | static void __exit cpufreq_gov_dbs_exit(void) |
| 479 | { |
| 480 | /* Make sure that the scheduled work is indeed not running */ |
| 481 | flush_scheduled_work(); |
| 482 | |
| 483 | cpufreq_unregister_governor(&cpufreq_gov_dbs); |
| 484 | } |
| 485 | |
| 486 | |
| 487 | MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); |
| 488 | MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " |
| 489 | "Low Latency Frequency Transition capable processors"); |
| 490 | MODULE_LICENSE ("GPL"); |
| 491 | |
| 492 | module_init(cpufreq_gov_dbs_init); |
| 493 | module_exit(cpufreq_gov_dbs_exit); |