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 (!cpufreq_frequency_get_table(cpu))
 184                 return;
 185
 186         if (policy && !policy_is_shared(policy)) {
 187                 pr_debug("%s: Free sysfs stat\n", __func__);
 188                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 189         }
 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(u64);
 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 void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 268 {
 269         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
 270                         policy->last_cpu);
 271
 272         pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
 273                         policy->cpu, policy->last_cpu);
 274         per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
 275                         policy->last_cpu);
 276         per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 277         stat->cpu = policy->cpu;
 278 }
 279
 280 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 281                 unsigned long val, void *data)
 282 {
 283         int ret;
 284         struct cpufreq_policy *policy = data;
 285         struct cpufreq_frequency_table *table;
 286         unsigned int cpu = policy->cpu;
 287
 288         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 289                 cpufreq_stats_update_policy_cpu(policy);
 290                 return 0;
 291         }
 292
 293         if (val != CPUFREQ_NOTIFY)
 294                 return 0;
 295         table = cpufreq_frequency_get_table(cpu);
 296         if (!table)
 297                 return 0;
 298         ret = cpufreq_stats_create_table(policy, table);
 299         if (ret)
 300                 return ret;
 301         return 0;
 302 }
 303
 304 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 305                 unsigned long val, void *data)
 306 {
 307         struct cpufreq_freqs *freq = data;
 308         struct cpufreq_stats *stat;
 309         int old_index, new_index;
 310
 311         if (val != CPUFREQ_POSTCHANGE)
 312                 return 0;
 313
 314         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 315         if (!stat)
 316                 return 0;
 317
 318         old_index = stat->last_index;
 319         new_index = freq_table_get_index(stat, freq->new);
 320
 321         /* We can't do stat->time_in_state[-1]= .. */
 322         if (old_index == -1 || new_index == -1)
 323                 return 0;
 324
 325         cpufreq_stats_update(freq->cpu);
 326
 327         if (old_index == new_index)
 328                 return 0;
 329
 330         spin_lock(&cpufreq_stats_lock);
 331         stat->last_index = new_index;
 332 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 333         stat->trans_table[old_index * stat->max_state + new_index]++;
 334 #endif
 335         stat->total_trans++;
 336         spin_unlock(&cpufreq_stats_lock);
 337         return 0;
 338 }
 339
 340 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 341                                                unsigned long action,
 342                                                void *hcpu)
 343 {
 344         unsigned int cpu = (unsigned long)hcpu;
 345
 346         switch (action) {
 347         case CPU_ONLINE:
 348         case CPU_ONLINE_FROZEN:
 349                 cpufreq_update_policy(cpu);
 350                 break;
 351         case CPU_DOWN_PREPARE:
 352         case CPU_DOWN_PREPARE_FROZEN:
 353                 cpufreq_stats_free_sysfs(cpu);
 354                 break;
 355         case CPU_DEAD:
 356         case CPU_DEAD_FROZEN:
 357                 cpufreq_stats_free_table(cpu);
 358                 break;
 359         }
 360         return NOTIFY_OK;
 361 }
 362
 363 /* priority=1 so this will get called before cpufreq_remove_dev */
 364 static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
 365         .notifier_call = cpufreq_stat_cpu_callback,
 366         .priority = 1,
 367 };
 368
 369 static struct notifier_block notifier_policy_block = {
 370         .notifier_call = cpufreq_stat_notifier_policy
 371 };
 372
 373 static struct notifier_block notifier_trans_block = {
 374         .notifier_call = cpufreq_stat_notifier_trans
 375 };
 376
 377 static int __init cpufreq_stats_init(void)
 378 {
 379         int ret;
 380         unsigned int cpu;
 381
 382         spin_lock_init(&cpufreq_stats_lock);
 383         ret = cpufreq_register_notifier(&notifier_policy_block,
 384                                 CPUFREQ_POLICY_NOTIFIER);
 385         if (ret)
 386                 return ret;
 387
 388         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 389         for_each_online_cpu(cpu)
 390                 cpufreq_update_policy(cpu);
 391
 392         ret = cpufreq_register_notifier(&notifier_trans_block,
 393                                 CPUFREQ_TRANSITION_NOTIFIER);
 394         if (ret) {
 395                 cpufreq_unregister_notifier(&notifier_policy_block,
 396                                 CPUFREQ_POLICY_NOTIFIER);
 397                 unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 398                 for_each_online_cpu(cpu)
 399                         cpufreq_stats_free_table(cpu);
 400                 return ret;
 401         }
 402
 403         return 0;
 404 }
 405 static void __exit cpufreq_stats_exit(void)
 406 {
 407         unsigned int cpu;
 408
 409         cpufreq_unregister_notifier(&notifier_policy_block,
 410                         CPUFREQ_POLICY_NOTIFIER);
 411         cpufreq_unregister_notifier(&notifier_trans_block,
 412                         CPUFREQ_TRANSITION_NOTIFIER);
 413         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 414         for_each_online_cpu(cpu) {
 415                 cpufreq_stats_free_table(cpu);
 416                 cpufreq_stats_free_sysfs(cpu);
 417         }
 418 }
 419
 420 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 421 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 422                                 "through sysfs filesystem");
 423 MODULE_LICENSE("GPL");
 424
 425 module_init(cpufreq_stats_init);
 426 module_exit(cpufreq_stats_exit);