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/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <asm/cputime.h>
  17
  18 static spinlock_t cpufreq_stats_lock;
  19
  20 struct cpufreq_stats {
  21         unsigned int cpu;
  22         unsigned int total_trans;
  23         unsigned long long last_time;
  24         unsigned int max_state;
  25         unsigned int state_num;
  26         unsigned int last_index;
  27         u64 *time_in_state;
  28         unsigned int *freq_table;
  29 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  30         unsigned int *trans_table;
  31 #endif
  32 };
  33
  34 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  35
  36 struct cpufreq_stats_attribute {
  37         struct attribute attr;
  38         ssize_t(*show) (struct cpufreq_stats *, char *);
  39 };
  40
  41 static int cpufreq_stats_update(unsigned int cpu)
  42 {
  43         struct cpufreq_stats *stat;
  44         unsigned long long cur_time;
  45
  46         cur_time = get_jiffies_64();
  47         spin_lock(&cpufreq_stats_lock);
  48         stat = per_cpu(cpufreq_stats_table, cpu);
  49         if (stat->time_in_state)
  50                 stat->time_in_state[stat->last_index] +=
  51                         cur_time - stat->last_time;
  52         stat->last_time = cur_time;
  53         spin_unlock(&cpufreq_stats_lock);
  54         return 0;
  55 }
  56
  57 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  58 {
  59         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  60         if (!stat)
  61                 return 0;
  62         return sprintf(buf, "%d\n",
  63                         per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  64 }
  65
  66 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  67 {
  68         ssize_t len = 0;
  69         int i;
  70         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  71         if (!stat)
  72                 return 0;
  73         cpufreq_stats_update(stat->cpu);
  74         for (i = 0; i < stat->state_num; i++) {
  75                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  76                         (unsigned long long)
  77                         jiffies_64_to_clock_t(stat->time_in_state[i]));
  78         }
  79         return len;
  80 }
  81
  82 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  83 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  84 {
  85         ssize_t len = 0;
  86         int i, j;
  87
  88         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  89         if (!stat)
  90                 return 0;
  91         cpufreq_stats_update(stat->cpu);
  92         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  93         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  94         for (i = 0; i < stat->state_num; i++) {
  95                 if (len >= PAGE_SIZE)
  96                         break;
  97                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  98                                 stat->freq_table[i]);
  99         }
 100         if (len >= PAGE_SIZE)
 101                 return PAGE_SIZE;
 102
 103         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 104
 105         for (i = 0; i < stat->state_num; i++) {
 106                 if (len >= PAGE_SIZE)
 107                         break;
 108
 109                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 110                                 stat->freq_table[i]);
 111
 112                 for (j = 0; j < stat->state_num; j++) {
 113                         if (len >= PAGE_SIZE)
 114                                 break;
 115                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 116                                         stat->trans_table[i*stat->max_state+j]);
 117                 }
 118                 if (len >= PAGE_SIZE)
 119                         break;
 120                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 121         }
 122         if (len >= PAGE_SIZE)
 123                 return PAGE_SIZE;
 124         return len;
 125 }
 126 cpufreq_freq_attr_ro(trans_table);
 127 #endif
 128
 129 cpufreq_freq_attr_ro(total_trans);
 130 cpufreq_freq_attr_ro(time_in_state);
 131
 132 static struct attribute *default_attrs[] = {
 133         &total_trans.attr,
 134         &time_in_state.attr,
 135 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 136         &trans_table.attr,
 137 #endif
 138         NULL
 139 };
 140 static struct attribute_group stats_attr_group = {
 141         .attrs = default_attrs,
 142         .name = "stats"
 143 };
 144
 145 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 146 {
 147         int index;
 148         for (index = 0; index < stat->max_state; index++)
 149                 if (stat->freq_table[index] == freq)
 150                         return index;
 151         return -1;
 152 }
 153
 154 /* should be called late in the CPU removal sequence so that the stats
 155  * memory is still available in case someone tries to use it.
 156  */
 157 static void cpufreq_stats_free_table(unsigned int cpu)
 158 {
 159         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 160
 161         if (stat) {
 162                 pr_debug("%s: Free stat table\n", __func__);
 163                 kfree(stat->time_in_state);
 164                 kfree(stat);
 165                 per_cpu(cpufreq_stats_table, cpu) = NULL;
 166         }
 167 }
 168
 169 /* must be called early in the CPU removal sequence (before
 170  * cpufreq_remove_dev) so that policy is still valid.
 171  */
 172 static void cpufreq_stats_free_sysfs(unsigned int cpu)
 173 {
 174         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 175
 176         if (!policy)
 177                 return;
 178
 179         if (!cpufreq_frequency_get_table(cpu))
 180                 goto put_ref;
 181
 182         if (!policy_is_shared(policy)) {
 183                 pr_debug("%s: Free sysfs stat\n", __func__);
 184                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 185         }
 186
 187 put_ref:
 188         cpufreq_cpu_put(policy);
 189 }
 190
 191 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
 192                 struct cpufreq_frequency_table *table)
 193 {
 194         unsigned int i, j, count = 0, ret = 0;
 195         struct cpufreq_stats *stat;
 196         struct cpufreq_policy *current_policy;
 197         unsigned int alloc_size;
 198         unsigned int cpu = policy->cpu;
 199         if (per_cpu(cpufreq_stats_table, cpu))
 200                 return -EBUSY;
 201         stat = kzalloc(sizeof(*stat), GFP_KERNEL);
 202         if ((stat) == NULL)
 203                 return -ENOMEM;
 204
 205         current_policy = cpufreq_cpu_get(cpu);
 206         if (current_policy == NULL) {
 207                 ret = -EINVAL;
 208                 goto error_get_fail;
 209         }
 210
 211         ret = sysfs_create_group(&current_policy->kobj, &stats_attr_group);
 212         if (ret)
 213                 goto error_out;
 214
 215         stat->cpu = cpu;
 216         per_cpu(cpufreq_stats_table, cpu) = stat;
 217
 218         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 219                 unsigned int freq = table[i].frequency;
 220                 if (freq == CPUFREQ_ENTRY_INVALID)
 221                         continue;
 222                 count++;
 223         }
 224
 225         alloc_size = count * sizeof(int) + count * sizeof(u64);
 226
 227 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 228         alloc_size += count * count * sizeof(int);
 229 #endif
 230         stat->max_state = count;
 231         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 232         if (!stat->time_in_state) {
 233                 ret = -ENOMEM;
 234                 goto error_out;
 235         }
 236         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 237
 238 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 239         stat->trans_table = stat->freq_table + count;
 240 #endif
 241         j = 0;
 242         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 243                 unsigned int freq = table[i].frequency;
 244                 if (freq == CPUFREQ_ENTRY_INVALID)
 245                         continue;
 246                 if (freq_table_get_index(stat, freq) == -1)
 247                         stat->freq_table[j++] = freq;
 248         }
 249         stat->state_num = j;
 250         spin_lock(&cpufreq_stats_lock);
 251         stat->last_time = get_jiffies_64();
 252         stat->last_index = freq_table_get_index(stat, policy->cur);
 253         spin_unlock(&cpufreq_stats_lock);
 254         cpufreq_cpu_put(current_policy);
 255         return 0;
 256 error_out:
 257         cpufreq_cpu_put(current_policy);
 258 error_get_fail:
 259         kfree(stat);
 260         per_cpu(cpufreq_stats_table, cpu) = NULL;
 261         return ret;
 262 }
 263
 264 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 265 {
 266         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
 267                         policy->last_cpu);
 268
 269         pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
 270                         policy->cpu, policy->last_cpu);
 271         per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
 272                         policy->last_cpu);
 273         per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 274         stat->cpu = policy->cpu;
 275 }
 276
 277 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 278                 unsigned long val, void *data)
 279 {
 280         int ret;
 281         struct cpufreq_policy *policy = data;
 282         struct cpufreq_frequency_table *table;
 283         unsigned int cpu = policy->cpu;
 284
 285         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 286                 cpufreq_stats_update_policy_cpu(policy);
 287                 return 0;
 288         }
 289
 290         if (val != CPUFREQ_NOTIFY)
 291                 return 0;
 292         table = cpufreq_frequency_get_table(cpu);
 293         if (!table)
 294                 return 0;
 295         ret = cpufreq_stats_create_table(policy, table);
 296         if (ret)
 297                 return ret;
 298         return 0;
 299 }
 300
 301 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 302                 unsigned long val, void *data)
 303 {
 304         struct cpufreq_freqs *freq = data;
 305         struct cpufreq_stats *stat;
 306         int old_index, new_index;
 307
 308         if (val != CPUFREQ_POSTCHANGE)
 309                 return 0;
 310
 311         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 312         if (!stat)
 313                 return 0;
 314
 315         old_index = stat->last_index;
 316         new_index = freq_table_get_index(stat, freq->new);
 317
 318         /* We can't do stat->time_in_state[-1]= .. */
 319         if (old_index == -1 || new_index == -1)
 320                 return 0;
 321
 322         cpufreq_stats_update(freq->cpu);
 323
 324         if (old_index == new_index)
 325                 return 0;
 326
 327         spin_lock(&cpufreq_stats_lock);
 328         stat->last_index = new_index;
 329 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 330         stat->trans_table[old_index * stat->max_state + new_index]++;
 331 #endif
 332         stat->total_trans++;
 333         spin_unlock(&cpufreq_stats_lock);
 334         return 0;
 335 }
 336
 337 static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 338                                                unsigned long action,
 339                                                void *hcpu)
 340 {
 341         unsigned int cpu = (unsigned long)hcpu;
 342
 343         switch (action) {
 344         case CPU_DOWN_PREPARE:
 345                 cpufreq_stats_free_sysfs(cpu);
 346                 break;
 347         case CPU_DEAD:
 348                 cpufreq_stats_free_table(cpu);
 349                 break;
 350         }
 351         return NOTIFY_OK;
 352 }
 353
 354 /* priority=1 so this will get called before cpufreq_remove_dev */
 355 static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
 356         .notifier_call = cpufreq_stat_cpu_callback,
 357         .priority = 1,
 358 };
 359
 360 static struct notifier_block notifier_policy_block = {
 361         .notifier_call = cpufreq_stat_notifier_policy
 362 };
 363
 364 static struct notifier_block notifier_trans_block = {
 365         .notifier_call = cpufreq_stat_notifier_trans
 366 };
 367
 368 static int __init cpufreq_stats_init(void)
 369 {
 370         int ret;
 371         unsigned int cpu;
 372
 373         spin_lock_init(&cpufreq_stats_lock);
 374         ret = cpufreq_register_notifier(&notifier_policy_block,
 375                                 CPUFREQ_POLICY_NOTIFIER);
 376         if (ret)
 377                 return ret;
 378
 379         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 380
 381         ret = cpufreq_register_notifier(&notifier_trans_block,
 382                                 CPUFREQ_TRANSITION_NOTIFIER);
 383         if (ret) {
 384                 cpufreq_unregister_notifier(&notifier_policy_block,
 385                                 CPUFREQ_POLICY_NOTIFIER);
 386                 unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 387                 for_each_online_cpu(cpu)
 388                         cpufreq_stats_free_table(cpu);
 389                 return ret;
 390         }
 391
 392         return 0;
 393 }
 394 static void __exit cpufreq_stats_exit(void)
 395 {
 396         unsigned int cpu;
 397
 398         cpufreq_unregister_notifier(&notifier_policy_block,
 399                         CPUFREQ_POLICY_NOTIFIER);
 400         cpufreq_unregister_notifier(&notifier_trans_block,
 401                         CPUFREQ_TRANSITION_NOTIFIER);
 402         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 403         for_each_online_cpu(cpu) {
 404                 cpufreq_stats_free_table(cpu);
 405                 cpufreq_stats_free_sysfs(cpu);
 406         }
 407 }
 408
 409 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 410 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 411                                 "through sysfs filesystem");
 412 MODULE_LICENSE("GPL");
 413
 414 module_init(cpufreq_stats_init);
 415 module_exit(cpufreq_stats_exit);