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