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/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysdev.h>
  15 #include <linux/cpu.h>
  16 #include <linux/sysfs.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/percpu.h>
  20 #include <linux/kobject.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/notifier.h>
  23 #include <asm/cputime.h>
  24
  25 static spinlock_t cpufreq_stats_lock;
  26
  27 #define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
  28 static struct freq_attr _attr_##_name = {\
  29         .attr = {.name = __stringify(_name), .mode = _mode, }, \
  30         .show = _show,\
  31 };
  32
  33 struct cpufreq_stats {
  34         unsigned int cpu;
  35         unsigned int total_trans;
  36         unsigned long long  last_time;
  37         unsigned int max_state;
  38         unsigned int state_num;
  39         unsigned int last_index;
  40         cputime64_t *time_in_state;
  41         unsigned int *freq_table;
  42 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  43         unsigned int *trans_table;
  44 #endif
  45 };
  46
  47 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  48
  49 struct cpufreq_stats_attribute {
  50         struct attribute attr;
  51         ssize_t(*show) (struct cpufreq_stats *, char *);
  52 };
  53
  54 static int cpufreq_stats_update(unsigned int cpu)
  55 {
  56         struct cpufreq_stats *stat;
  57         unsigned long long cur_time;
  58
  59         cur_time = get_jiffies_64();
  60         spin_lock(&cpufreq_stats_lock);
  61         stat = per_cpu(cpufreq_stats_table, cpu);
  62         if (stat->time_in_state)
  63                 stat->time_in_state[stat->last_index] =
  64                         cputime64_add(stat->time_in_state[stat->last_index],
  65                                       cputime_sub(cur_time, stat->last_time));
  66         stat->last_time = cur_time;
  67         spin_unlock(&cpufreq_stats_lock);
  68         return 0;
  69 }
  70
  71 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  72 {
  73         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  74         if (!stat)
  75                 return 0;
  76         return sprintf(buf, "%d\n",
  77                         per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  78 }
  79
  80 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  81 {
  82         ssize_t len = 0;
  83         int i;
  84         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  85         if (!stat)
  86                 return 0;
  87         cpufreq_stats_update(stat->cpu);
  88         for (i = 0; i < stat->state_num; i++) {
  89                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  90                         (unsigned long long)
  91                         cputime64_to_clock_t(stat->time_in_state[i]));
  92         }
  93         return len;
  94 }
  95
  96 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  97 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  98 {
  99         ssize_t len = 0;
 100         int i, j;
 101
 102         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 103         if (!stat)
 104                 return 0;
 105         cpufreq_stats_update(stat->cpu);
 106         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 107         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 108         for (i = 0; i < stat->state_num; i++) {
 109                 if (len >= PAGE_SIZE)
 110                         break;
 111                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 112                                 stat->freq_table[i]);
 113         }
 114         if (len >= PAGE_SIZE)
 115                 return PAGE_SIZE;
 116
 117         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 118
 119         for (i = 0; i < stat->state_num; i++) {
 120                 if (len >= PAGE_SIZE)
 121                         break;
 122
 123                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 124                                 stat->freq_table[i]);
 125
 126                 for (j = 0; j < stat->state_num; j++)   {
 127                         if (len >= PAGE_SIZE)
 128                                 break;
 129                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 130                                         stat->trans_table[i*stat->max_state+j]);
 131                 }
 132                 if (len >= PAGE_SIZE)
 133                         break;
 134                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 135         }
 136         if (len >= PAGE_SIZE)
 137                 return PAGE_SIZE;
 138         return len;
 139 }
 140 CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
 141 #endif
 142
 143 CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
 144 CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
 145
 146 static struct attribute *default_attrs[] = {
 147         &_attr_total_trans.attr,
 148         &_attr_time_in_state.attr,
 149 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 150         &_attr_trans_table.attr,
 151 #endif
 152         NULL
 153 };
 154 static struct attribute_group stats_attr_group = {
 155         .attrs = default_attrs,
 156         .name = "stats"
 157 };
 158
 159 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 160 {
 161         int index;
 162         for (index = 0; index < stat->max_state; index++)
 163                 if (stat->freq_table[index] == freq)
 164                         return index;
 165         return -1;
 166 }
 167
 168 static void cpufreq_stats_free_table(unsigned int cpu)
 169 {
 170         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 171         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 172         if (policy && policy->cpu == cpu)
 173                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 174         if (stat) {
 175                 kfree(stat->time_in_state);
 176                 kfree(stat);
 177         }
 178         per_cpu(cpufreq_stats_table, cpu) = NULL;
 179         if (policy)
 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 *data;
 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(struct cpufreq_stats), GFP_KERNEL);
 194         if ((stat) == NULL)
 195                 return -ENOMEM;
 196
 197         data = cpufreq_cpu_get(cpu);
 198         if (data == NULL) {
 199                 ret = -EINVAL;
 200                 goto error_get_fail;
 201         }
 202
 203         ret = sysfs_create_group(&data->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(cputime64_t);
 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(data);
 247         return 0;
 248 error_out:
 249         cpufreq_cpu_put(data);
 250 error_get_fail:
 251         kfree(stat);
 252         per_cpu(cpufreq_stats_table, cpu) = NULL;
 253         return ret;
 254 }
 255
 256 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 257                 unsigned long val, void *data)
 258 {
 259         int ret;
 260         struct cpufreq_policy *policy = data;
 261         struct cpufreq_frequency_table *table;
 262         unsigned int cpu = policy->cpu;
 263         if (val != CPUFREQ_NOTIFY)
 264                 return 0;
 265         table = cpufreq_frequency_get_table(cpu);
 266         if (!table)
 267                 return 0;
 268         ret = cpufreq_stats_create_table(policy, table);
 269         if (ret)
 270                 return ret;
 271         return 0;
 272 }
 273
 274 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 275                 unsigned long val, void *data)
 276 {
 277         struct cpufreq_freqs *freq = data;
 278         struct cpufreq_stats *stat;
 279         int old_index, new_index;
 280
 281         if (val != CPUFREQ_POSTCHANGE)
 282                 return 0;
 283
 284         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 285         if (!stat)
 286                 return 0;
 287
 288         old_index = stat->last_index;
 289         new_index = freq_table_get_index(stat, freq->new);
 290
 291         cpufreq_stats_update(freq->cpu);
 292         if (old_index == new_index)
 293                 return 0;
 294
 295         if (old_index == -1 || new_index == -1)
 296                 return 0;
 297
 298         spin_lock(&cpufreq_stats_lock);
 299         stat->last_index = new_index;
 300 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 301         stat->trans_table[old_index * stat->max_state + new_index]++;
 302 #endif
 303         stat->total_trans++;
 304         spin_unlock(&cpufreq_stats_lock);
 305         return 0;
 306 }
 307
 308 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 309                                                unsigned long action,
 310                                                void *hcpu)
 311 {
 312         unsigned int cpu = (unsigned long)hcpu;
 313
 314         switch (action) {
 315         case CPU_ONLINE:
 316         case CPU_ONLINE_FROZEN:
 317                 cpufreq_update_policy(cpu);
 318                 break;
 319         case CPU_DEAD:
 320         case CPU_DEAD_FROZEN:
 321                 cpufreq_stats_free_table(cpu);
 322                 break;
 323         }
 324         return NOTIFY_OK;
 325 }
 326
 327 static struct notifier_block cpufreq_stat_cpu_notifier __refdata =
 328 {
 329         .notifier_call = cpufreq_stat_cpu_callback,
 330 };
 331
 332 static struct notifier_block notifier_policy_block = {
 333         .notifier_call = cpufreq_stat_notifier_policy
 334 };
 335
 336 static struct notifier_block notifier_trans_block = {
 337         .notifier_call = cpufreq_stat_notifier_trans
 338 };
 339
 340 static int __init cpufreq_stats_init(void)
 341 {
 342         int ret;
 343         unsigned int cpu;
 344
 345         spin_lock_init(&cpufreq_stats_lock);
 346         ret = cpufreq_register_notifier(&notifier_policy_block,
 347                                 CPUFREQ_POLICY_NOTIFIER);
 348         if (ret)
 349                 return ret;
 350
 351         ret = cpufreq_register_notifier(&notifier_trans_block,
 352                                 CPUFREQ_TRANSITION_NOTIFIER);
 353         if (ret) {
 354                 cpufreq_unregister_notifier(&notifier_policy_block,
 355                                 CPUFREQ_POLICY_NOTIFIER);
 356                 return ret;
 357         }
 358
 359         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 360         for_each_online_cpu(cpu) {
 361                 cpufreq_update_policy(cpu);
 362         }
 363         return 0;
 364 }
 365 static void __exit cpufreq_stats_exit(void)
 366 {
 367         unsigned int cpu;
 368
 369         cpufreq_unregister_notifier(&notifier_policy_block,
 370                         CPUFREQ_POLICY_NOTIFIER);
 371         cpufreq_unregister_notifier(&notifier_trans_block,
 372                         CPUFREQ_TRANSITION_NOTIFIER);
 373         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 374         for_each_online_cpu(cpu) {
 375                 cpufreq_stats_free_table(cpu);
 376         }
 377 }
 378
 379 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 380 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 381                                 "through sysfs filesystem");
 382 MODULE_LICENSE("GPL");
 383
 384 module_init(cpufreq_stats_init);
 385 module_exit(cpufreq_stats_exit);