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/sysdev.h>
  14 #include <linux/cpu.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/percpu.h>
  19 #include <linux/kobject.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/notifier.h>
  22 #include <asm/cputime.h>
  23
  24 static spinlock_t cpufreq_stats_lock;
  25
  26 #define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
  27 static struct freq_attr _attr_##_name = {\
  28         .attr = {.name = __stringify(_name), .mode = _mode, }, \
  29         .show = _show,\
  30 };
  31
  32 struct cpufreq_stats {
  33         unsigned int cpu;
  34         unsigned int total_trans;
  35         unsigned long long  last_time;
  36         unsigned int max_state;
  37         unsigned int state_num;
  38         unsigned int last_index;
  39         cputime64_t *time_in_state;
  40         unsigned int *freq_table;
  41 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  42         unsigned int *trans_table;
  43 #endif
  44 };
  45
  46 static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
  47
  48 struct cpufreq_stats_attribute {
  49         struct attribute attr;
  50         ssize_t(*show) (struct cpufreq_stats *, char *);
  51 };
  52
  53 static int
  54 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 = 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
  72 show_total_trans(struct cpufreq_policy *policy, char *buf)
  73 {
  74         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  75         if (!stat)
  76                 return 0;
  77         return sprintf(buf, "%d\n",
  78                         cpufreq_stats_table[stat->cpu]->total_trans);
  79 }
  80
  81 static ssize_t
  82 show_time_in_state(struct cpufreq_policy *policy, char *buf)
  83 {
  84         ssize_t len = 0;
  85         int i;
  86         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  87         if (!stat)
  88                 return 0;
  89         cpufreq_stats_update(stat->cpu);
  90         for (i = 0; i < stat->state_num; i++) {
  91                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  92                         (unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
  93         }
  94         return len;
  95 }
  96
  97 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  98 static ssize_t
  99 show_trans_table(struct cpufreq_policy *policy, char *buf)
 100 {
 101         ssize_t len = 0;
 102         int i, j;
 103
 104         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
 105         if (!stat)
 106                 return 0;
 107         cpufreq_stats_update(stat->cpu);
 108         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 109         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 110         for (i = 0; i < stat->state_num; i++) {
 111                 if (len >= PAGE_SIZE)
 112                         break;
 113                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 114                                 stat->freq_table[i]);
 115         }
 116         if (len >= PAGE_SIZE)
 117                 return len;
 118
 119         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 120
 121         for (i = 0; i < stat->state_num; i++) {
 122                 if (len >= PAGE_SIZE)
 123                         break;
 124
 125                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 126                                 stat->freq_table[i]);
 127
 128                 for (j = 0; j < stat->state_num; j++)   {
 129                         if (len >= PAGE_SIZE)
 130                                 break;
 131                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 132                                         stat->trans_table[i*stat->max_state+j]);
 133                 }
 134                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 135         }
 136         return len;
 137 }
 138 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
 139 #endif
 140
 141 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
 142 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
 143
 144 static struct attribute *default_attrs[] = {
 145         &_attr_total_trans.attr,
 146         &_attr_time_in_state.attr,
 147 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 148         &_attr_trans_table.attr,
 149 #endif
 150         NULL
 151 };
 152 static struct attribute_group stats_attr_group = {
 153         .attrs = default_attrs,
 154         .name = "stats"
 155 };
 156
 157 static int
 158 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 159 {
 160         int index;
 161         for (index = 0; index < stat->max_state; index++)
 162                 if (stat->freq_table[index] == freq)
 163                         return index;
 164         return -1;
 165 }
 166
 167 static void
 168 cpufreq_stats_free_table (unsigned int cpu)
 169 {
 170         struct cpufreq_stats *stat = 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         cpufreq_stats_table[cpu] = NULL;
 179         if (policy)
 180                 cpufreq_cpu_put(policy);
 181 }
 182
 183 static int
 184 cpufreq_stats_create_table (struct cpufreq_policy *policy,
 185                 struct cpufreq_frequency_table *table)
 186 {
 187         unsigned int i, j, count = 0, ret = 0;
 188         struct cpufreq_stats *stat;
 189         struct cpufreq_policy *data;
 190         unsigned int alloc_size;
 191         unsigned int cpu = policy->cpu;
 192         if (cpufreq_stats_table[cpu])
 193                 return -EBUSY;
 194         if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == 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         if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 204                 goto error_out;
 205
 206         stat->cpu = cpu;
 207         cpufreq_stats_table[cpu] = stat;
 208
 209         for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 210                 unsigned int freq = table[i].frequency;
 211                 if (freq == CPUFREQ_ENTRY_INVALID)
 212                         continue;
 213                 count++;
 214         }
 215
 216         alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
 217
 218 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 219         alloc_size += count * count * sizeof(int);
 220 #endif
 221         stat->max_state = count;
 222         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 223         if (!stat->time_in_state) {
 224                 ret = -ENOMEM;
 225                 goto error_out;
 226         }
 227         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 228
 229 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 230         stat->trans_table = stat->freq_table + count;
 231 #endif
 232         j = 0;
 233         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 234                 unsigned int freq = table[i].frequency;
 235                 if (freq == CPUFREQ_ENTRY_INVALID)
 236                         continue;
 237                 if (freq_table_get_index(stat, freq) == -1)
 238                         stat->freq_table[j++] = freq;
 239         }
 240         stat->state_num = j;
 241         spin_lock(&cpufreq_stats_lock);
 242         stat->last_time = get_jiffies_64();
 243         stat->last_index = freq_table_get_index(stat, policy->cur);
 244         spin_unlock(&cpufreq_stats_lock);
 245         cpufreq_cpu_put(data);
 246         return 0;
 247 error_out:
 248         cpufreq_cpu_put(data);
 249 error_get_fail:
 250         kfree(stat);
 251         cpufreq_stats_table[cpu] = NULL;
 252         return ret;
 253 }
 254
 255 static int
 256 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 257                 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         if ((ret = cpufreq_stats_create_table(policy, table)))
 269                 return ret;
 270         return 0;
 271 }
 272
 273 static int
 274 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 275                 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 = cpufreq_stats_table[freq->cpu];
 285         if (!stat)
 286                 return 0;
 287
 288         old_index = freq_table_get_index(stat, freq->old);
 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 cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 309                                         unsigned long action, void *hcpu)
 310 {
 311         unsigned int cpu = (unsigned long)hcpu;
 312
 313         switch (action) {
 314         case CPU_ONLINE:
 315         case CPU_ONLINE_FROZEN:
 316                 cpufreq_update_policy(cpu);
 317                 break;
 318         case CPU_DEAD:
 319         case CPU_DEAD_FROZEN:
 320                 cpufreq_stats_free_table(cpu);
 321                 break;
 322         }
 323         return NOTIFY_OK;
 324 }
 325
 326 static struct notifier_block cpufreq_stat_cpu_notifier =
 327 {
 328         .notifier_call = cpufreq_stat_cpu_callback,
 329 };
 330
 331 static struct notifier_block notifier_policy_block = {
 332         .notifier_call = cpufreq_stat_notifier_policy
 333 };
 334
 335 static struct notifier_block notifier_trans_block = {
 336         .notifier_call = cpufreq_stat_notifier_trans
 337 };
 338
 339 static int
 340 __init cpufreq_stats_init(void)
 341 {
 342         int ret;
 343         unsigned int cpu;
 344
 345         spin_lock_init(&cpufreq_stats_lock);
 346         if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 347                                 CPUFREQ_POLICY_NOTIFIER)))
 348                 return ret;
 349
 350         if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 351                                 CPUFREQ_TRANSITION_NOTIFIER))) {
 352                 cpufreq_unregister_notifier(&notifier_policy_block,
 353                                 CPUFREQ_POLICY_NOTIFIER);
 354                 return ret;
 355         }
 356
 357         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 358         for_each_online_cpu(cpu) {
 359                 cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
 360                                 CPU_ONLINE, (void *)(long)cpu);
 361         }
 362         return 0;
 363 }
 364 static void
 365 __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_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
 376                                                 CPU_DEAD, (void *)(long)cpu);
 377         }
 378 }
 379
 380 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 381 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats"
 382                                 "through sysfs filesystem");
 383 MODULE_LICENSE ("GPL");
 384
 385 module_init(cpufreq_stats_init);
 386 module_exit(cpufreq_stats_exit);