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         cpufreq_stats_update(stats);
  72         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  73         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  74         for (i = 0; i < stats->state_num; i++) {
  75                 if (len >= PAGE_SIZE)
  76                         break;
  77                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  78                                 stats->freq_table[i]);
  79         }
  80         if (len >= PAGE_SIZE)
  81                 return PAGE_SIZE;
  82
  83         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
  84
  85         for (i = 0; i < stats->state_num; i++) {
  86                 if (len >= PAGE_SIZE)
  87                         break;
  88
  89                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
  90                                 stats->freq_table[i]);
  91
  92                 for (j = 0; j < stats->state_num; j++) {
  93                         if (len >= PAGE_SIZE)
  94                                 break;
  95                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  96                                         stats->trans_table[i*stats->max_state+j]);
  97                 }
  98                 if (len >= PAGE_SIZE)
  99                         break;
 100                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 101         }
 102         if (len >= PAGE_SIZE)
 103                 return PAGE_SIZE;
 104         return len;
 105 }
 106 cpufreq_freq_attr_ro(trans_table);
 107 #endif
 108
 109 cpufreq_freq_attr_ro(total_trans);
 110 cpufreq_freq_attr_ro(time_in_state);
 111
 112 static struct attribute *default_attrs[] = {
 113         &total_trans.attr,
 114         &time_in_state.attr,
 115 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 116         &trans_table.attr,
 117 #endif
 118         NULL
 119 };
 120 static struct attribute_group stats_attr_group = {
 121         .attrs = default_attrs,
 122         .name = "stats"
 123 };
 124
 125 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 126 {
 127         int index;
 128         for (index = 0; index < stats->max_state; index++)
 129                 if (stats->freq_table[index] == freq)
 130                         return index;
 131         return -1;
 132 }
 133
 134 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 135 {
 136         struct cpufreq_stats *stats = policy->stats;
 137
 138         /* Already freed */
 139         if (!stats)
 140                 return;
 141
 142         pr_debug("%s: Free stats table\n", __func__);
 143
 144         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 145         kfree(stats->time_in_state);
 146         kfree(stats);
 147         policy->stats = NULL;
 148 }
 149
 150 static void cpufreq_stats_free_table(unsigned int cpu)
 151 {
 152         struct cpufreq_policy *policy;
 153
 154         policy = cpufreq_cpu_get(cpu);
 155         if (!policy)
 156                 return;
 157
 158         __cpufreq_stats_free_table(policy);
 159
 160         cpufreq_cpu_put(policy);
 161 }
 162
 163 static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
 164 {
 165         unsigned int i = 0, count = 0, ret = -ENOMEM;
 166         struct cpufreq_stats *stats;
 167         unsigned int alloc_size;
 168         unsigned int cpu = policy->cpu;
 169         struct cpufreq_frequency_table *pos, *table;
 170
 171         /* We need cpufreq table for creating stats table */
 172         table = cpufreq_frequency_get_table(cpu);
 173         if (unlikely(!table))
 174                 return 0;
 175
 176         /* stats already initialized */
 177         if (policy->stats)
 178                 return -EEXIST;
 179
 180         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 181         if (!stats)
 182                 return -ENOMEM;
 183
 184         /* Find total allocation size */
 185         cpufreq_for_each_valid_entry(pos, table)
 186                 count++;
 187
 188         alloc_size = count * sizeof(int) + count * sizeof(u64);
 189
 190 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 191         alloc_size += count * count * sizeof(int);
 192 #endif
 193
 194         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 195         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 196         if (!stats->time_in_state)
 197                 goto free_stat;
 198
 199         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 200
 201 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 202         stats->trans_table = stats->freq_table + count;
 203 #endif
 204
 205         stats->max_state = count;
 206
 207         /* Find valid-unique entries */
 208         cpufreq_for_each_valid_entry(pos, table)
 209                 if (freq_table_get_index(stats, pos->frequency) == -1)
 210                         stats->freq_table[i++] = pos->frequency;
 211         stats->state_num = i;
 212
 213         spin_lock(&cpufreq_stats_lock);
 214         stats->last_time = get_jiffies_64();
 215         stats->last_index = freq_table_get_index(stats, policy->cur);
 216         spin_unlock(&cpufreq_stats_lock);
 217
 218         policy->stats = stats;
 219         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 220         if (!ret)
 221                 return 0;
 222
 223         /* We failed, release resources */
 224         policy->stats = NULL;
 225         kfree(stats->time_in_state);
 226 free_stat:
 227         kfree(stats);
 228
 229         return ret;
 230 }
 231
 232 static void cpufreq_stats_create_table(unsigned int cpu)
 233 {
 234         struct cpufreq_policy *policy;
 235
 236         /*
 237          * "likely(!policy)" because normally cpufreq_stats will be registered
 238          * before cpufreq driver
 239          */
 240         policy = cpufreq_cpu_get(cpu);
 241         if (likely(!policy))
 242                 return;
 243
 244         __cpufreq_stats_create_table(policy);
 245
 246         cpufreq_cpu_put(policy);
 247 }
 248
 249 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 250                 unsigned long val, void *data)
 251 {
 252         int ret = 0;
 253         struct cpufreq_policy *policy = data;
 254
 255         if (val == CPUFREQ_CREATE_POLICY)
 256                 ret = __cpufreq_stats_create_table(policy);
 257         else if (val == CPUFREQ_REMOVE_POLICY)
 258                 __cpufreq_stats_free_table(policy);
 259
 260         return ret;
 261 }
 262
 263 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 264                 unsigned long val, void *data)
 265 {
 266         struct cpufreq_freqs *freq = data;
 267         struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
 268         struct cpufreq_stats *stats;
 269         int old_index, new_index;
 270
 271         if (!policy) {
 272                 pr_err("%s: No policy found\n", __func__);
 273                 return 0;
 274         }
 275
 276         if (val != CPUFREQ_POSTCHANGE)
 277                 goto put_policy;
 278
 279         if (!policy->stats) {
 280                 pr_debug("%s: No stats found\n", __func__);
 281                 goto put_policy;
 282         }
 283
 284         stats = policy->stats;
 285
 286         old_index = stats->last_index;
 287         new_index = freq_table_get_index(stats, freq->new);
 288
 289         /* We can't do stats->time_in_state[-1]= .. */
 290         if (old_index == -1 || new_index == -1)
 291                 goto put_policy;
 292
 293         cpufreq_stats_update(stats);
 294
 295         if (old_index == new_index)
 296                 goto put_policy;
 297
 298         spin_lock(&cpufreq_stats_lock);
 299         stats->last_index = new_index;
 300 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 301         stats->trans_table[old_index * stats->max_state + new_index]++;
 302 #endif
 303         stats->total_trans++;
 304         spin_unlock(&cpufreq_stats_lock);
 305
 306 put_policy:
 307         cpufreq_cpu_put(policy);
 308         return 0;
 309 }
 310
 311 static struct notifier_block notifier_policy_block = {
 312         .notifier_call = cpufreq_stat_notifier_policy
 313 };
 314
 315 static struct notifier_block notifier_trans_block = {
 316         .notifier_call = cpufreq_stat_notifier_trans
 317 };
 318
 319 static int __init cpufreq_stats_init(void)
 320 {
 321         int ret;
 322         unsigned int cpu;
 323
 324         spin_lock_init(&cpufreq_stats_lock);
 325         ret = cpufreq_register_notifier(&notifier_policy_block,
 326                                 CPUFREQ_POLICY_NOTIFIER);
 327         if (ret)
 328                 return ret;
 329
 330         for_each_online_cpu(cpu)
 331                 cpufreq_stats_create_table(cpu);
 332
 333         ret = cpufreq_register_notifier(&notifier_trans_block,
 334                                 CPUFREQ_TRANSITION_NOTIFIER);
 335         if (ret) {
 336                 cpufreq_unregister_notifier(&notifier_policy_block,
 337                                 CPUFREQ_POLICY_NOTIFIER);
 338                 for_each_online_cpu(cpu)
 339                         cpufreq_stats_free_table(cpu);
 340                 return ret;
 341         }
 342
 343         return 0;
 344 }
 345 static void __exit cpufreq_stats_exit(void)
 346 {
 347         unsigned int cpu;
 348
 349         cpufreq_unregister_notifier(&notifier_policy_block,
 350                         CPUFREQ_POLICY_NOTIFIER);
 351         cpufreq_unregister_notifier(&notifier_trans_block,
 352                         CPUFREQ_TRANSITION_NOTIFIER);
 353         for_each_online_cpu(cpu)
 354                 cpufreq_stats_free_table(cpu);
 355 }
 356
 357 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 358 MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
 359 MODULE_LICENSE("GPL");
 360
 361 module_init(cpufreq_stats_init);
 362 module_exit(cpufreq_stats_exit);