drivers/cpufreq/cpufreq_stats.c

   1 /*
   2  *  drivers/cpufreq/cpufreq_stats.c
   3  *
   4  *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
   5  *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysdev.h>
  15 #include <linux/cpu.h>
  16 #include <linux/sysfs.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/percpu.h>
  20 #include <linux/kobject.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/notifier.h>
  23 #include <asm/cputime.h>
  24
  25 static spinlock_t cpufreq_stats_lock;
  26
  27 #define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
  28 static struct freq_attr _attr_##_name = {\
  29         .attr = {.name = __stringify(_name), .mode = _mode, }, \
  30         .show = _show,\
  31 };
  32
  33 struct cpufreq_stats {
  34         unsigned int cpu;
  35         unsigned int total_trans;
  36         unsigned long long  last_time;
  37         unsigned int max_state;
  38         unsigned int state_num;
  39         unsigned int last_index;
  40         cputime64_t *time_in_state;
  41         unsigned int *freq_table;
  42 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  43         unsigned int *trans_table;
  44 #endif
  45 };
  46
  47 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  48
  49 struct cpufreq_stats_attribute {
  50         struct attribute attr;
  51         ssize_t(*show) (struct cpufreq_stats *, char *);
  52 };
  53
  54 static int cpufreq_stats_update(unsigned int cpu)
  55 {
  56         struct cpufreq_stats *stat;
  57         unsigned long long cur_time;
  58
  59         cur_time = get_jiffies_64();
  60         spin_lock(&cpufreq_stats_lock);
  61         stat = per_cpu(cpufreq_stats_table, cpu);
  62         if (stat->time_in_state)
  63                 stat->time_in_state[stat->last_index] =
  64                         cputime64_add(stat->time_in_state[stat->last_index],
  65                                       cputime_sub(cur_time, stat->last_time));
  66         stat->last_time = cur_time;
  67         spin_unlock(&cpufreq_stats_lock);
  68         return 0;
  69 }
  70
  71 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  72 {
  73         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  74         if (!stat)
  75                 return 0;
  76         return sprintf(buf, "%d\n",
  77                         per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  78 }
  79
  80 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  81 {
  82         ssize_t len = 0;
  83         int i;
  84         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  85         if (!stat)
  86                 return 0;
  87         cpufreq_stats_update(stat->cpu);
  88         for (i = 0; i < stat->state_num; i++) {
  89                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  90                         (unsigned long long)
  91                         cputime64_to_clock_t(stat->time_in_state[i]));
  92         }
  93         return len;
  94 }
  95
  96 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  97 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  98 {
  99         ssize_t len = 0;
 100         int i, j;
 101
 102         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 103         if (!stat)
 104                 return 0;
 105         cpufreq_stats_update(stat->cpu);
 106         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 107         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 108         for (i = 0; i < stat->state_num; i++) {
 109                 if (len >= PAGE_SIZE)
 110                         break;
 111                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 112                                 stat->freq_table[i]);
 113         }
 114         if (len >= PAGE_SIZE)
 115                 return PAGE_SIZE;
 116
 117         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 118
 119         for (i = 0; i < stat->state_num; i++) {
 120                 if (len >= PAGE_SIZE)
 121                         break;
 122
 123                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 124                                 stat->freq_table[i]);
 125
 126                 for (j = 0; j < stat->state_num; j++)   {
 127                         if (len >= PAGE_SIZE)
 128                                 break;
 129                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 130                                         stat->trans_table[i*stat->max_state+j]);
 131                 }
 132                 if (len >= PAGE_SIZE)
 133                         break;
 134                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 135         }
 136         if (len >= PAGE_SIZE)
 137                 return PAGE_SIZE;
 138         return len;
 139 }
 140 CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
 141 #endif
 142
 143 CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
 144 CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
 145
 146 static struct attribute *default_attrs[] = {
 147         &_attr_total_trans.attr,
 148         &_attr_time_in_state.attr,
 149 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 150         &_attr_trans_table.attr,
 151 #endif
 152         NULL
 153 };
 154 static struct attribute_group stats_attr_group = {
 155         .attrs = default_attrs,
 156         .name = "stats"
 157 };
 158
 159 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 160 {
 161         int index;
 162         for (index = 0; index < stat->max_state; index++)
 163                 if (stat->freq_table[index] == freq)
 164                         return index;
 165         return -1;
 166 }
 167
 168 /* should be called late in the CPU removal sequence so that the stats
 169  * memory is still available in case someone tries to use it.
 170  */
 171 static void cpufreq_stats_free_table(unsigned int cpu)
 172 {
 173         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 174         if (stat) {
 175                 kfree(stat->time_in_state);
 176                 kfree(stat);
 177         }
 178         per_cpu(cpufreq_stats_table, cpu) = NULL;
 179 }
 180
 181 /* must be called early in the CPU removal sequence (before
 182  * cpufreq_remove_dev) so that policy is still valid.
 183  */
 184 static void cpufreq_stats_free_sysfs(unsigned int cpu)
 185 {
 186         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 187         if (policy && policy->cpu == cpu)
 188                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 189         if (policy)
 190                 cpufreq_cpu_put(policy);
 191 }
 192
 193 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
 194                 struct cpufreq_frequency_table *table)
 195 {
 196         unsigned int i, j, count = 0, ret = 0;
 197         struct cpufreq_stats *stat;
 198         struct cpufreq_policy *data;
 199         unsigned int alloc_size;
 200         unsigned int cpu = policy->cpu;
 201         if (per_cpu(cpufreq_stats_table, cpu))
 202                 return -EBUSY;
 203         stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
 204         if ((stat) == NULL)
 205                 return -ENOMEM;
 206
 207         data = cpufreq_cpu_get(cpu);
 208         if (data == NULL) {
 209                 ret = -EINVAL;
 210                 goto error_get_fail;
 211         }
 212
 213         ret = sysfs_create_group(&data->kobj, &stats_attr_group);
 214         if (ret)
 215                 goto error_out;
 216
 217         stat->cpu = cpu;
 218         per_cpu(cpufreq_stats_table, cpu) = stat;
 219
 220         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 221                 unsigned int freq = table[i].frequency;
 222                 if (freq == CPUFREQ_ENTRY_INVALID)
 223                         continue;
 224                 count++;
 225         }
 226
 227         alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
 228
 229 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 230         alloc_size += count * count * sizeof(int);
 231 #endif
 232         stat->max_state = count;
 233         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 234         if (!stat->time_in_state) {
 235                 ret = -ENOMEM;
 236                 goto error_out;
 237         }
 238         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 239
 240 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 241         stat->trans_table = stat->freq_table + count;
 242 #endif
 243         j = 0;
 244         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 245                 unsigned int freq = table[i].frequency;
 246                 if (freq == CPUFREQ_ENTRY_INVALID)
 247                         continue;
 248                 if (freq_table_get_index(stat, freq) == -1)
 249                         stat->freq_table[j++] = freq;
 250         }
 251         stat->state_num = j;
 252         spin_lock(&cpufreq_stats_lock);
 253         stat->last_time = get_jiffies_64();
 254         stat->last_index = freq_table_get_index(stat, policy->cur);
 255         spin_unlock(&cpufreq_stats_lock);
 256         cpufreq_cpu_put(data);
 257         return 0;
 258 error_out:
 259         cpufreq_cpu_put(data);
 260 error_get_fail:
 261         kfree(stat);
 262         per_cpu(cpufreq_stats_table, cpu) = NULL;
 263         return ret;
 264 }
 265
 266 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 267                 unsigned long val, void *data)
 268 {
 269         int ret;
 270         struct cpufreq_policy *policy = data;
 271         struct cpufreq_frequency_table *table;
 272         unsigned int cpu = policy->cpu;
 273         if (val != CPUFREQ_NOTIFY)
 274                 return 0;
 275         table = cpufreq_frequency_get_table(cpu);
 276         if (!table)
 277                 return 0;
 278         ret = cpufreq_stats_create_table(policy, table);
 279         if (ret)
 280                 return ret;
 281         return 0;
 282 }
 283
 284 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 285                 unsigned long val, void *data)
 286 {
 287         struct cpufreq_freqs *freq = data;
 288         struct cpufreq_stats *stat;
 289         int old_index, new_index;
 290
 291         if (val != CPUFREQ_POSTCHANGE)
 292                 return 0;
 293
 294         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 295         if (!stat)
 296                 return 0;
 297
 298         old_index = stat->last_index;
 299         new_index = freq_table_get_index(stat, freq->new);
 300
 301         /* We can't do stat->time_in_state[-1]= .. */
 302         if (old_index == -1 || new_index == -1)
 303                 return 0;
 304
 305         cpufreq_stats_update(freq->cpu);
 306
 307         if (old_index == new_index)
 308                 return 0;
 309
 310         spin_lock(&cpufreq_stats_lock);
 311         stat->last_index = new_index;
 312 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 313         stat->trans_table[old_index * stat->max_state + new_index]++;
 314 #endif
 315         stat->total_trans++;
 316         spin_unlock(&cpufreq_stats_lock);
 317         return 0;
 318 }
 319
 320 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 321                                                unsigned long action,
 322                                                void *hcpu)
 323 {
 324         unsigned int cpu = (unsigned long)hcpu;
 325
 326         switch (action) {
 327         case CPU_ONLINE:
 328         case CPU_ONLINE_FROZEN:
 329                 cpufreq_update_policy(cpu);
 330                 break;
 331         case CPU_DOWN_PREPARE:
 332                 cpufreq_stats_free_sysfs(cpu);
 333                 break;
 334         case CPU_DEAD:
 335         case CPU_DEAD_FROZEN:
 336                 cpufreq_stats_free_table(cpu);
 337                 break;
 338         }
 339         return NOTIFY_OK;
 340 }
 341
 342 /* priority=1 so this will get called before cpufreq_remove_dev */
 343 static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
 344         .notifier_call = cpufreq_stat_cpu_callback,
 345         .priority = 1,
 346 };
 347
 348 static struct notifier_block notifier_policy_block = {
 349         .notifier_call = cpufreq_stat_notifier_policy
 350 };
 351
 352 static struct notifier_block notifier_trans_block = {
 353         .notifier_call = cpufreq_stat_notifier_trans
 354 };
 355
 356 static int __init cpufreq_stats_init(void)
 357 {
 358         int ret;
 359         unsigned int cpu;
 360
 361         spin_lock_init(&cpufreq_stats_lock);
 362         ret = cpufreq_register_notifier(&notifier_policy_block,
 363                                 CPUFREQ_POLICY_NOTIFIER);
 364         if (ret)
 365                 return ret;
 366
 367         ret = cpufreq_register_notifier(&notifier_trans_block,
 368                                 CPUFREQ_TRANSITION_NOTIFIER);
 369         if (ret) {
 370                 cpufreq_unregister_notifier(&notifier_policy_block,
 371                                 CPUFREQ_POLICY_NOTIFIER);
 372                 return ret;
 373         }
 374
 375         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 376         for_each_online_cpu(cpu) {
 377                 cpufreq_update_policy(cpu);
 378         }
 379         return 0;
 380 }
 381 static void __exit cpufreq_stats_exit(void)
 382 {
 383         unsigned int cpu;
 384
 385         cpufreq_unregister_notifier(&notifier_policy_block,
 386                         CPUFREQ_POLICY_NOTIFIER);
 387         cpufreq_unregister_notifier(&notifier_trans_block,
 388                         CPUFREQ_TRANSITION_NOTIFIER);
 389         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 390         for_each_online_cpu(cpu) {
 391                 cpufreq_stats_free_table(cpu);
 392                 cpufreq_stats_free_sysfs(cpu);
 393         }
 394 }
 395
 396 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 397 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 398                                 "through sysfs filesystem");
 399 MODULE_LICENSE("GPL");
 400
 401 module_init(cpufreq_stats_init);
 402 module_exit(cpufreq_stats_exit);