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/cpu.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/module.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 struct cpufreq_stats {
  28         unsigned int cpu;
  29         unsigned int total_trans;
  30         unsigned long long  last_time;
  31         unsigned int max_state;
  32         unsigned int state_num;
  33         unsigned int last_index;
  34         u64 *time_in_state;
  35         unsigned int *freq_table;
  36 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  37         unsigned int *trans_table;
  38 #endif
  39 };
  40
  41 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  42
  43 struct cpufreq_stats_attribute {
  44         struct attribute attr;
  45         ssize_t(*show) (struct cpufreq_stats *, char *);
  46 };
  47
  48 static int cpufreq_stats_update(unsigned int cpu)
  49 {
  50         struct cpufreq_stats *stat;
  51         unsigned long long cur_time;
  52
  53         cur_time = get_jiffies_64();
  54         spin_lock(&cpufreq_stats_lock);
  55         stat = per_cpu(cpufreq_stats_table, cpu);
  56         if (stat->time_in_state)
  57                 stat->time_in_state[stat->last_index] +=
  58                         cur_time - stat->last_time;
  59         stat->last_time = cur_time;
  60         spin_unlock(&cpufreq_stats_lock);
  61         return 0;
  62 }
  63
  64 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  65 {
  66         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  67         if (!stat)
  68                 return 0;
  69         return sprintf(buf, "%d\n",
  70                         per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  71 }
  72
  73 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  74 {
  75         ssize_t len = 0;
  76         int i;
  77         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  78         if (!stat)
  79                 return 0;
  80         cpufreq_stats_update(stat->cpu);
  81         for (i = 0; i < stat->state_num; i++) {
  82                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  83                         (unsigned long long)
  84                         cputime64_to_clock_t(stat->time_in_state[i]));
  85         }
  86         return len;
  87 }
  88
  89 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  90 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  91 {
  92         ssize_t len = 0;
  93         int i, j;
  94
  95         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  96         if (!stat)
  97                 return 0;
  98         cpufreq_stats_update(stat->cpu);
  99         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 100         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 101         for (i = 0; i < stat->state_num; i++) {
 102                 if (len >= PAGE_SIZE)
 103                         break;
 104                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 105                                 stat->freq_table[i]);
 106         }
 107         if (len >= PAGE_SIZE)
 108                 return PAGE_SIZE;
 109
 110         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 111
 112         for (i = 0; i < stat->state_num; i++) {
 113                 if (len >= PAGE_SIZE)
 114                         break;
 115
 116                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 117                                 stat->freq_table[i]);
 118
 119                 for (j = 0; j < stat->state_num; j++)   {
 120                         if (len >= PAGE_SIZE)
 121                                 break;
 122                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 123                                         stat->trans_table[i*stat->max_state+j]);
 124                 }
 125                 if (len >= PAGE_SIZE)
 126                         break;
 127                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 128         }
 129         if (len >= PAGE_SIZE)
 130                 return PAGE_SIZE;
 131         return len;
 132 }
 133 cpufreq_freq_attr_ro(trans_table);
 134 #endif
 135
 136 cpufreq_freq_attr_ro(total_trans);
 137 cpufreq_freq_attr_ro(time_in_state);
 138
 139 static struct attribute *default_attrs[] = {
 140         &total_trans.attr,
 141         &time_in_state.attr,
 142 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 143         &trans_table.attr,
 144 #endif
 145         NULL
 146 };
 147 static struct attribute_group stats_attr_group = {
 148         .attrs = default_attrs,
 149         .name = "stats"
 150 };
 151
 152 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 153 {
 154         int index;
 155         for (index = 0; index < stat->max_state; index++)
 156                 if (stat->freq_table[index] == freq)
 157                         return index;
 158         return -1;
 159 }
 160
 161 /* should be called late in the CPU removal sequence so that the stats
 162  * memory is still available in case someone tries to use it.
 163  */
 164 static void cpufreq_stats_free_table(unsigned int cpu)
 165 {
 166         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 167
 168         if (stat) {
 169                 pr_debug("%s: Free stat table\n", __func__);
 170                 kfree(stat->time_in_state);
 171                 kfree(stat);
 172                 per_cpu(cpufreq_stats_table, cpu) = NULL;
 173         }
 174 }
 175
 176 /* must be called early in the CPU removal sequence (before
 177  * cpufreq_remove_dev) so that policy is still valid.
 178  */
 179 static void cpufreq_stats_free_sysfs(unsigned int cpu)
 180 {
 181         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 182
 183         if (!policy)
 184                 return;
 185
 186         if (!cpufreq_frequency_get_table(cpu))
 187                 goto put_ref;
 188
 189         if (!policy_is_shared(policy)) {
 190                 pr_debug("%s: Free sysfs stat\n", __func__);
 191                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 192         }
 193
 194 put_ref:
 195         cpufreq_cpu_put(policy);
 196 }
 197
 198 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
 199                 struct cpufreq_frequency_table *table)
 200 {
 201         unsigned int i, j, count = 0, ret = 0;
 202         struct cpufreq_stats *stat;
 203         struct cpufreq_policy *data;
 204         unsigned int alloc_size;
 205         unsigned int cpu = policy->cpu;
 206         if (per_cpu(cpufreq_stats_table, cpu))
 207                 return -EBUSY;
 208         stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
 209         if ((stat) == NULL)
 210                 return -ENOMEM;
 211
 212         data = cpufreq_cpu_get(cpu);
 213         if (data == NULL) {
 214                 ret = -EINVAL;
 215                 goto error_get_fail;
 216         }
 217
 218         ret = sysfs_create_group(&data->kobj, &stats_attr_group);
 219         if (ret)
 220                 goto error_out;
 221
 222         stat->cpu = cpu;
 223         per_cpu(cpufreq_stats_table, cpu) = stat;
 224
 225         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 226                 unsigned int freq = table[i].frequency;
 227                 if (freq == CPUFREQ_ENTRY_INVALID)
 228                         continue;
 229                 count++;
 230         }
 231
 232         alloc_size = count * sizeof(int) + count * sizeof(u64);
 233
 234 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 235         alloc_size += count * count * sizeof(int);
 236 #endif
 237         stat->max_state = count;
 238         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 239         if (!stat->time_in_state) {
 240                 ret = -ENOMEM;
 241                 goto error_out;
 242         }
 243         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 244
 245 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 246         stat->trans_table = stat->freq_table + count;
 247 #endif
 248         j = 0;
 249         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 250                 unsigned int freq = table[i].frequency;
 251                 if (freq == CPUFREQ_ENTRY_INVALID)
 252                         continue;
 253                 if (freq_table_get_index(stat, freq) == -1)
 254                         stat->freq_table[j++] = freq;
 255         }
 256         stat->state_num = j;
 257         spin_lock(&cpufreq_stats_lock);
 258         stat->last_time = get_jiffies_64();
 259         stat->last_index = freq_table_get_index(stat, policy->cur);
 260         spin_unlock(&cpufreq_stats_lock);
 261         cpufreq_cpu_put(data);
 262         return 0;
 263 error_out:
 264         cpufreq_cpu_put(data);
 265 error_get_fail:
 266         kfree(stat);
 267         per_cpu(cpufreq_stats_table, cpu) = NULL;
 268         return ret;
 269 }
 270
 271 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 272 {
 273         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
 274                         policy->last_cpu);
 275
 276         pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
 277                         policy->cpu, policy->last_cpu);
 278         per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
 279                         policy->last_cpu);
 280         per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 281         stat->cpu = policy->cpu;
 282 }
 283
 284 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 285                 unsigned long val, void *data)
 286 {
 287         int ret;
 288         struct cpufreq_policy *policy = data;
 289         struct cpufreq_frequency_table *table;
 290         unsigned int cpu = policy->cpu;
 291
 292         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 293                 cpufreq_stats_update_policy_cpu(policy);
 294                 return 0;
 295         }
 296
 297         if (val != CPUFREQ_NOTIFY)
 298                 return 0;
 299         table = cpufreq_frequency_get_table(cpu);
 300         if (!table)
 301                 return 0;
 302         ret = cpufreq_stats_create_table(policy, table);
 303         if (ret)
 304                 return ret;
 305         return 0;
 306 }
 307
 308 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 309                 unsigned long val, void *data)
 310 {
 311         struct cpufreq_freqs *freq = data;
 312         struct cpufreq_stats *stat;
 313         int old_index, new_index;
 314
 315         if (val != CPUFREQ_POSTCHANGE)
 316                 return 0;
 317
 318         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 319         if (!stat)
 320                 return 0;
 321
 322         old_index = stat->last_index;
 323         new_index = freq_table_get_index(stat, freq->new);
 324
 325         /* We can't do stat->time_in_state[-1]= .. */
 326         if (old_index == -1 || new_index == -1)
 327                 return 0;
 328
 329         cpufreq_stats_update(freq->cpu);
 330
 331         if (old_index == new_index)
 332                 return 0;
 333
 334         spin_lock(&cpufreq_stats_lock);
 335         stat->last_index = new_index;
 336 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 337         stat->trans_table[old_index * stat->max_state + new_index]++;
 338 #endif
 339         stat->total_trans++;
 340         spin_unlock(&cpufreq_stats_lock);
 341         return 0;
 342 }
 343
 344 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 345                                                unsigned long action,
 346                                                void *hcpu)
 347 {
 348         unsigned int cpu = (unsigned long)hcpu;
 349
 350         switch (action) {
 351         case CPU_ONLINE:
 352                 cpufreq_update_policy(cpu);
 353                 break;
 354         case CPU_DOWN_PREPARE:
 355                 cpufreq_stats_free_sysfs(cpu);
 356                 break;
 357         case CPU_DEAD:
 358                 cpufreq_stats_free_table(cpu);
 359                 break;
 360         case CPU_UP_CANCELED_FROZEN:
 361                 cpufreq_stats_free_sysfs(cpu);
 362                 cpufreq_stats_free_table(cpu);
 363                 break;
 364         }
 365         return NOTIFY_OK;
 366 }
 367
 368 /* priority=1 so this will get called before cpufreq_remove_dev */
 369 static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
 370         .notifier_call = cpufreq_stat_cpu_callback,
 371         .priority = 1,
 372 };
 373
 374 static struct notifier_block notifier_policy_block = {
 375         .notifier_call = cpufreq_stat_notifier_policy
 376 };
 377
 378 static struct notifier_block notifier_trans_block = {
 379         .notifier_call = cpufreq_stat_notifier_trans
 380 };
 381
 382 static int __init cpufreq_stats_init(void)
 383 {
 384         int ret;
 385         unsigned int cpu;
 386
 387         spin_lock_init(&cpufreq_stats_lock);
 388         ret = cpufreq_register_notifier(&notifier_policy_block,
 389                                 CPUFREQ_POLICY_NOTIFIER);
 390         if (ret)
 391                 return ret;
 392
 393         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 394         for_each_online_cpu(cpu)
 395                 cpufreq_update_policy(cpu);
 396
 397         ret = cpufreq_register_notifier(&notifier_trans_block,
 398                                 CPUFREQ_TRANSITION_NOTIFIER);
 399         if (ret) {
 400                 cpufreq_unregister_notifier(&notifier_policy_block,
 401                                 CPUFREQ_POLICY_NOTIFIER);
 402                 unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 403                 for_each_online_cpu(cpu)
 404                         cpufreq_stats_free_table(cpu);
 405                 return ret;
 406         }
 407
 408         return 0;
 409 }
 410 static void __exit cpufreq_stats_exit(void)
 411 {
 412         unsigned int cpu;
 413
 414         cpufreq_unregister_notifier(&notifier_policy_block,
 415                         CPUFREQ_POLICY_NOTIFIER);
 416         cpufreq_unregister_notifier(&notifier_trans_block,
 417                         CPUFREQ_TRANSITION_NOTIFIER);
 418         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 419         for_each_online_cpu(cpu) {
 420                 cpufreq_stats_free_table(cpu);
 421                 cpufreq_stats_free_sysfs(cpu);
 422         }
 423 }
 424
 425 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 426 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 427                                 "through sysfs filesystem");
 428 MODULE_LICENSE("GPL");
 429
 430 module_init(cpufreq_stats_init);
 431 module_exit(cpufreq_stats_exit);