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