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 <linux/cputime.h>
  17
  18 static spinlock_t cpufreq_stats_lock;
  19
  20 struct cpufreq_stats {
  21         unsigned int total_trans;
  22         unsigned long long last_time;
  23         unsigned int max_state;
  24         unsigned int state_num;
  25         unsigned int last_index;
  26         u64 *time_in_state;
  27         unsigned int *freq_table;
  28 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  29         unsigned int *trans_table;
  30 #endif
  31 };
  32
  33 static int cpufreq_stats_update(struct cpufreq_stats *stats)
  34 {
  35         unsigned long long cur_time = get_jiffies_64();
  36
  37         spin_lock(&cpufreq_stats_lock);
  38         stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
  39         stats->last_time = cur_time;
  40         spin_unlock(&cpufreq_stats_lock);
  41         return 0;
  42 }
  43
  44 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  45 {
  46         return sprintf(buf, "%d\n", policy->stats->total_trans);
  47 }
  48
  49 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  50 {
  51         struct cpufreq_stats *stats = policy->stats;
  52         ssize_t len = 0;
  53         int i;
  54
  55         cpufreq_stats_update(stats);
  56         for (i = 0; i < stats->state_num; i++) {
  57                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  58                         (unsigned long long)
  59                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  60         }
  61         return len;
  62 }
  63
  64 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  65 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  66 {
  67         struct cpufreq_stats *stats = policy->stats;
  68         ssize_t len = 0;
  69         int i, j;
  70
  71         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  72         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  73         for (i = 0; i < stats->state_num; i++) {
  74                 if (len >= PAGE_SIZE)
  75                         break;
  76                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  77                                 stats->freq_table[i]);
  78         }
  79         if (len >= PAGE_SIZE)
  80                 return PAGE_SIZE;
  81
  82         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
  83
  84         for (i = 0; i < stats->state_num; i++) {
  85                 if (len >= PAGE_SIZE)
  86                         break;
  87
  88                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
  89                                 stats->freq_table[i]);
  90
  91                 for (j = 0; j < stats->state_num; j++) {
  92                         if (len >= PAGE_SIZE)
  93                                 break;
  94                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  95                                         stats->trans_table[i*stats->max_state+j]);
  96                 }
  97                 if (len >= PAGE_SIZE)
  98                         break;
  99                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 100         }
 101         if (len >= PAGE_SIZE)
 102                 return PAGE_SIZE;
 103         return len;
 104 }
 105 cpufreq_freq_attr_ro(trans_table);
 106 #endif
 107
 108 cpufreq_freq_attr_ro(total_trans);
 109 cpufreq_freq_attr_ro(time_in_state);
 110
 111 static struct attribute *default_attrs[] = {
 112         &total_trans.attr,
 113         &time_in_state.attr,
 114 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 115         &trans_table.attr,
 116 #endif
 117         NULL
 118 };
 119 static struct attribute_group stats_attr_group = {
 120         .attrs = default_attrs,
 121         .name = "stats"
 122 };
 123
 124 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 125 {
 126         int index;
 127         for (index = 0; index < stats->max_state; index++)
 128                 if (stats->freq_table[index] == freq)
 129                         return index;
 130         return -1;
 131 }
 132
 133 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 134 {
 135         struct cpufreq_stats *stats = policy->stats;
 136
 137         /* Already freed */
 138         if (!stats)
 139                 return;
 140
 141         pr_debug("%s: Free stats table\n", __func__);
 142
 143         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 144         kfree(stats->time_in_state);
 145         kfree(stats);
 146         policy->stats = NULL;
 147 }
 148
 149 static void cpufreq_stats_free_table(unsigned int cpu)
 150 {
 151         struct cpufreq_policy *policy;
 152
 153         policy = cpufreq_cpu_get(cpu);
 154         if (!policy)
 155                 return;
 156
 157         __cpufreq_stats_free_table(policy);
 158
 159         cpufreq_cpu_put(policy);
 160 }
 161
 162 static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
 163 {
 164         unsigned int i = 0, count = 0, ret = -ENOMEM;
 165         struct cpufreq_stats *stats;
 166         unsigned int alloc_size;
 167         unsigned int cpu = policy->cpu;
 168         struct cpufreq_frequency_table *pos, *table;
 169
 170         /* We need cpufreq table for creating stats table */
 171         table = cpufreq_frequency_get_table(cpu);
 172         if (unlikely(!table))
 173                 return 0;
 174
 175         /* stats already initialized */
 176         if (policy->stats)
 177                 return -EEXIST;
 178
 179         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 180         if (!stats)
 181                 return -ENOMEM;
 182
 183         /* Find total allocation size */
 184         cpufreq_for_each_valid_entry(pos, table)
 185                 count++;
 186
 187         alloc_size = count * sizeof(int) + count * sizeof(u64);
 188
 189 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 190         alloc_size += count * count * sizeof(int);
 191 #endif
 192
 193         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 194         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 195         if (!stats->time_in_state)
 196                 goto free_stat;
 197
 198         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 199
 200 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 201         stats->trans_table = stats->freq_table + count;
 202 #endif
 203
 204         stats->max_state = count;
 205
 206         /* Find valid-unique entries */
 207         cpufreq_for_each_valid_entry(pos, table)
 208                 if (freq_table_get_index(stats, pos->frequency) == -1)
 209                         stats->freq_table[i++] = pos->frequency;
 210
 211         stats->state_num = i;
 212         stats->last_time = get_jiffies_64();
 213         stats->last_index = freq_table_get_index(stats, policy->cur);
 214
 215         policy->stats = stats;
 216         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 217         if (!ret)
 218                 return 0;
 219
 220         /* We failed, release resources */
 221         policy->stats = NULL;
 222         kfree(stats->time_in_state);
 223 free_stat:
 224         kfree(stats);
 225
 226         return ret;
 227 }
 228
 229 static void cpufreq_stats_create_table(unsigned int cpu)
 230 {
 231         struct cpufreq_policy *policy;
 232
 233         /*
 234          * "likely(!policy)" because normally cpufreq_stats will be registered
 235          * before cpufreq driver
 236          */
 237         policy = cpufreq_cpu_get(cpu);
 238         if (likely(!policy))
 239                 return;
 240
 241         __cpufreq_stats_create_table(policy);
 242
 243         cpufreq_cpu_put(policy);
 244 }
 245
 246 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 247                 unsigned long val, void *data)
 248 {
 249         int ret = 0;
 250         struct cpufreq_policy *policy = data;
 251
 252         if (val == CPUFREQ_CREATE_POLICY)
 253                 ret = __cpufreq_stats_create_table(policy);
 254         else if (val == CPUFREQ_REMOVE_POLICY)
 255                 __cpufreq_stats_free_table(policy);
 256
 257         return ret;
 258 }
 259
 260 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 261                 unsigned long val, void *data)
 262 {
 263         struct cpufreq_freqs *freq = data;
 264         struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
 265         struct cpufreq_stats *stats;
 266         int old_index, new_index;
 267
 268         if (!policy) {
 269                 pr_err("%s: No policy found\n", __func__);
 270                 return 0;
 271         }
 272
 273         if (val != CPUFREQ_POSTCHANGE)
 274                 goto put_policy;
 275
 276         if (!policy->stats) {
 277                 pr_debug("%s: No stats found\n", __func__);
 278                 goto put_policy;
 279         }
 280
 281         stats = policy->stats;
 282
 283         old_index = stats->last_index;
 284         new_index = freq_table_get_index(stats, freq->new);
 285
 286         /* We can't do stats->time_in_state[-1]= .. */
 287         if (old_index == -1 || new_index == -1)
 288                 goto put_policy;
 289
 290         if (old_index == new_index)
 291                 goto put_policy;
 292
 293         cpufreq_stats_update(stats);
 294
 295         stats->last_index = new_index;
 296 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 297         stats->trans_table[old_index * stats->max_state + new_index]++;
 298 #endif
 299         stats->total_trans++;
 300
 301 put_policy:
 302         cpufreq_cpu_put(policy);
 303         return 0;
 304 }
 305
 306 static struct notifier_block notifier_policy_block = {
 307         .notifier_call = cpufreq_stat_notifier_policy
 308 };
 309
 310 static struct notifier_block notifier_trans_block = {
 311         .notifier_call = cpufreq_stat_notifier_trans
 312 };
 313
 314 static int __init cpufreq_stats_init(void)
 315 {
 316         int ret;
 317         unsigned int cpu;
 318
 319         spin_lock_init(&cpufreq_stats_lock);
 320         ret = cpufreq_register_notifier(&notifier_policy_block,
 321                                 CPUFREQ_POLICY_NOTIFIER);
 322         if (ret)
 323                 return ret;
 324
 325         for_each_online_cpu(cpu)
 326                 cpufreq_stats_create_table(cpu);
 327
 328         ret = cpufreq_register_notifier(&notifier_trans_block,
 329                                 CPUFREQ_TRANSITION_NOTIFIER);
 330         if (ret) {
 331                 cpufreq_unregister_notifier(&notifier_policy_block,
 332                                 CPUFREQ_POLICY_NOTIFIER);
 333                 for_each_online_cpu(cpu)
 334                         cpufreq_stats_free_table(cpu);
 335                 return ret;
 336         }
 337
 338         return 0;
 339 }
 340 static void __exit cpufreq_stats_exit(void)
 341 {
 342         unsigned int cpu;
 343
 344         cpufreq_unregister_notifier(&notifier_policy_block,
 345                         CPUFREQ_POLICY_NOTIFIER);
 346         cpufreq_unregister_notifier(&notifier_trans_block,
 347                         CPUFREQ_TRANSITION_NOTIFIER);
 348         for_each_online_cpu(cpu)
 349                 cpufreq_stats_free_table(cpu);
 350 }
 351
 352 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 353 MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
 354 MODULE_LICENSE("GPL");
 355
 356 module_init(cpufreq_stats_init);
 357 module_exit(cpufreq_stats_exit);