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