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 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 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 155 {
 156         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 157
 158         if (!stat)
 159                 return;
 160
 161         pr_debug("%s: Free stat table\n", __func__);
 162
 163         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 164         kfree(stat->time_in_state);
 165         kfree(stat);
 166         per_cpu(cpufreq_stats_table, policy->cpu) = NULL;
 167 }
 168
 169 static void cpufreq_stats_free_table(unsigned int cpu)
 170 {
 171         struct cpufreq_policy *policy;
 172
 173         policy = cpufreq_cpu_get(cpu);
 174         if (!policy)
 175                 return;
 176
 177         if (cpufreq_frequency_get_table(policy->cpu))
 178                 __cpufreq_stats_free_table(policy);
 179
 180         cpufreq_cpu_put(policy);
 181 }
 182
 183 static int __cpufreq_stats_create_table(struct cpufreq_policy *policy,
 184                 struct cpufreq_frequency_table *table)
 185 {
 186         unsigned int i, j, count = 0, ret = 0;
 187         struct cpufreq_stats *stat;
 188         struct cpufreq_policy *current_policy;
 189         unsigned int alloc_size;
 190         unsigned int cpu = policy->cpu;
 191         if (per_cpu(cpufreq_stats_table, cpu))
 192                 return -EBUSY;
 193         stat = kzalloc(sizeof(*stat), GFP_KERNEL);
 194         if ((stat) == NULL)
 195                 return -ENOMEM;
 196
 197         current_policy = cpufreq_cpu_get(cpu);
 198         if (current_policy == NULL) {
 199                 ret = -EINVAL;
 200                 goto error_get_fail;
 201         }
 202
 203         ret = sysfs_create_group(&current_policy->kobj, &stats_attr_group);
 204         if (ret)
 205                 goto error_out;
 206
 207         stat->cpu = cpu;
 208         per_cpu(cpufreq_stats_table, cpu) = stat;
 209
 210         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 211                 unsigned int freq = table[i].frequency;
 212                 if (freq == CPUFREQ_ENTRY_INVALID)
 213                         continue;
 214                 count++;
 215         }
 216
 217         alloc_size = count * sizeof(int) + count * sizeof(u64);
 218
 219 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 220         alloc_size += count * count * sizeof(int);
 221 #endif
 222         stat->max_state = count;
 223         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 224         if (!stat->time_in_state) {
 225                 ret = -ENOMEM;
 226                 goto error_out;
 227         }
 228         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 229
 230 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 231         stat->trans_table = stat->freq_table + count;
 232 #endif
 233         j = 0;
 234         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 235                 unsigned int freq = table[i].frequency;
 236                 if (freq == CPUFREQ_ENTRY_INVALID)
 237                         continue;
 238                 if (freq_table_get_index(stat, freq) == -1)
 239                         stat->freq_table[j++] = freq;
 240         }
 241         stat->state_num = j;
 242         spin_lock(&cpufreq_stats_lock);
 243         stat->last_time = get_jiffies_64();
 244         stat->last_index = freq_table_get_index(stat, policy->cur);
 245         spin_unlock(&cpufreq_stats_lock);
 246         cpufreq_cpu_put(current_policy);
 247         return 0;
 248 error_out:
 249         cpufreq_cpu_put(current_policy);
 250 error_get_fail:
 251         kfree(stat);
 252         per_cpu(cpufreq_stats_table, cpu) = NULL;
 253         return ret;
 254 }
 255
 256 static void cpufreq_stats_create_table(unsigned int cpu)
 257 {
 258         struct cpufreq_policy *policy;
 259         struct cpufreq_frequency_table *table;
 260
 261         /*
 262          * "likely(!policy)" because normally cpufreq_stats will be registered
 263          * before cpufreq driver
 264          */
 265         policy = cpufreq_cpu_get(cpu);
 266         if (likely(!policy))
 267                 return;
 268
 269         table = cpufreq_frequency_get_table(policy->cpu);
 270         if (likely(table))
 271                 __cpufreq_stats_create_table(policy, table);
 272
 273         cpufreq_cpu_put(policy);
 274 }
 275
 276 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 277 {
 278         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
 279                         policy->last_cpu);
 280
 281         pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
 282                         policy->cpu, policy->last_cpu);
 283         per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
 284                         policy->last_cpu);
 285         per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 286         stat->cpu = policy->cpu;
 287 }
 288
 289 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 290                 unsigned long val, void *data)
 291 {
 292         int ret = 0;
 293         struct cpufreq_policy *policy = data;
 294         struct cpufreq_frequency_table *table;
 295         unsigned int cpu = policy->cpu;
 296
 297         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 298                 cpufreq_stats_update_policy_cpu(policy);
 299                 return 0;
 300         }
 301
 302         table = cpufreq_frequency_get_table(cpu);
 303         if (!table)
 304                 return 0;
 305
 306         if (val == CPUFREQ_CREATE_POLICY)
 307                 ret = __cpufreq_stats_create_table(policy, table);
 308         else if (val == CPUFREQ_REMOVE_POLICY)
 309                 __cpufreq_stats_free_table(policy);
 310
 311         return ret;
 312 }
 313
 314 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 315                 unsigned long val, void *data)
 316 {
 317         struct cpufreq_freqs *freq = data;
 318         struct cpufreq_stats *stat;
 319         int old_index, new_index;
 320
 321         if (val != CPUFREQ_POSTCHANGE)
 322                 return 0;
 323
 324         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 325         if (!stat)
 326                 return 0;
 327
 328         old_index = stat->last_index;
 329         new_index = freq_table_get_index(stat, freq->new);
 330
 331         /* We can't do stat->time_in_state[-1]= .. */
 332         if (old_index == -1 || new_index == -1)
 333                 return 0;
 334
 335         cpufreq_stats_update(freq->cpu);
 336
 337         if (old_index == new_index)
 338                 return 0;
 339
 340         spin_lock(&cpufreq_stats_lock);
 341         stat->last_index = new_index;
 342 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 343         stat->trans_table[old_index * stat->max_state + new_index]++;
 344 #endif
 345         stat->total_trans++;
 346         spin_unlock(&cpufreq_stats_lock);
 347         return 0;
 348 }
 349
 350 static struct notifier_block notifier_policy_block = {
 351         .notifier_call = cpufreq_stat_notifier_policy
 352 };
 353
 354 static struct notifier_block notifier_trans_block = {
 355         .notifier_call = cpufreq_stat_notifier_trans
 356 };
 357
 358 static int __init cpufreq_stats_init(void)
 359 {
 360         int ret;
 361         unsigned int cpu;
 362
 363         spin_lock_init(&cpufreq_stats_lock);
 364         ret = cpufreq_register_notifier(&notifier_policy_block,
 365                                 CPUFREQ_POLICY_NOTIFIER);
 366         if (ret)
 367                 return ret;
 368
 369         for_each_online_cpu(cpu)
 370                 cpufreq_stats_create_table(cpu);
 371
 372         ret = cpufreq_register_notifier(&notifier_trans_block,
 373                                 CPUFREQ_TRANSITION_NOTIFIER);
 374         if (ret) {
 375                 cpufreq_unregister_notifier(&notifier_policy_block,
 376                                 CPUFREQ_POLICY_NOTIFIER);
 377                 for_each_online_cpu(cpu)
 378                         cpufreq_stats_free_table(cpu);
 379                 return ret;
 380         }
 381
 382         return 0;
 383 }
 384 static void __exit cpufreq_stats_exit(void)
 385 {
 386         unsigned int cpu;
 387
 388         cpufreq_unregister_notifier(&notifier_policy_block,
 389                         CPUFREQ_POLICY_NOTIFIER);
 390         cpufreq_unregister_notifier(&notifier_trans_block,
 391                         CPUFREQ_TRANSITION_NOTIFIER);
 392         for_each_online_cpu(cpu)
 393                 cpufreq_stats_free_table(cpu);
 394 }
 395
 396 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 397 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 398                                 "through sysfs filesystem");
 399 MODULE_LICENSE("GPL");
 400
 401 module_init(cpufreq_stats_init);
 402 module_exit(cpufreq_stats_exit);