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/config.h>
  13 #include <linux/kernel.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), .owner = THIS_MODULE, \
  30                 .mode = _mode, }, \
  31         .show = _show,\
  32 };
  33
  34 struct cpufreq_stats {
  35         unsigned int cpu;
  36         unsigned int total_trans;
  37         unsigned long long  last_time;
  38         unsigned int max_state;
  39         unsigned int state_num;
  40         unsigned int last_index;
  41         cputime64_t *time_in_state;
  42         unsigned int *freq_table;
  43 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  44         unsigned int *trans_table;
  45 #endif
  46 };
  47
  48 static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
  49
  50 struct cpufreq_stats_attribute {
  51         struct attribute attr;
  52         ssize_t(*show) (struct cpufreq_stats *, char *);
  53 };
  54
  55 static int
  56 cpufreq_stats_update (unsigned int cpu)
  57 {
  58         struct cpufreq_stats *stat;
  59         unsigned long long cur_time;
  60
  61         cur_time = get_jiffies_64();
  62         spin_lock(&cpufreq_stats_lock);
  63         stat = cpufreq_stats_table[cpu];
  64         if (stat->time_in_state)
  65                 stat->time_in_state[stat->last_index] =
  66                         cputime64_add(stat->time_in_state[stat->last_index],
  67                                       cputime_sub(cur_time, stat->last_time));
  68         stat->last_time = cur_time;
  69         spin_unlock(&cpufreq_stats_lock);
  70         return 0;
  71 }
  72
  73 static ssize_t
  74 show_total_trans(struct cpufreq_policy *policy, char *buf)
  75 {
  76         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  77         if (!stat)
  78                 return 0;
  79         return sprintf(buf, "%d\n",
  80                         cpufreq_stats_table[stat->cpu]->total_trans);
  81 }
  82
  83 static ssize_t
  84 show_time_in_state(struct cpufreq_policy *policy, char *buf)
  85 {
  86         ssize_t len = 0;
  87         int i;
  88         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  89         if (!stat)
  90                 return 0;
  91         cpufreq_stats_update(stat->cpu);
  92         for (i = 0; i < stat->state_num; i++) {
  93                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  94                         (unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
  95         }
  96         return len;
  97 }
  98
  99 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 100 static ssize_t
 101 show_trans_table(struct cpufreq_policy *policy, char *buf)
 102 {
 103         ssize_t len = 0;
 104         int i, j;
 105
 106         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
 107         if (!stat)
 108                 return 0;
 109         cpufreq_stats_update(stat->cpu);
 110         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 111         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 112         for (i = 0; i < stat->state_num; i++) {
 113                 if (len >= PAGE_SIZE)
 114                         break;
 115                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 116                                 stat->freq_table[i]);
 117         }
 118         if (len >= PAGE_SIZE)
 119                 return len;
 120
 121         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 122
 123         for (i = 0; i < stat->state_num; i++) {
 124                 if (len >= PAGE_SIZE)
 125                         break;
 126
 127                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 128                                 stat->freq_table[i]);
 129
 130                 for (j = 0; j < stat->state_num; j++)   {
 131                         if (len >= PAGE_SIZE)
 132                                 break;
 133                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 134                                         stat->trans_table[i*stat->max_state+j]);
 135                 }
 136                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 137         }
 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
 160 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 161 {
 162         int index;
 163         for (index = 0; index < stat->max_state; index++)
 164                 if (stat->freq_table[index] == freq)
 165                         return index;
 166         return -1;
 167 }
 168
 169 static void
 170 cpufreq_stats_free_table (unsigned int cpu)
 171 {
 172         struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
 173         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 174         if (policy && policy->cpu == cpu)
 175                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 176         if (stat) {
 177                 kfree(stat->time_in_state);
 178                 kfree(stat);
 179         }
 180         cpufreq_stats_table[cpu] = NULL;
 181         if (policy)
 182                 cpufreq_cpu_put(policy);
 183 }
 184
 185 static int
 186 cpufreq_stats_create_table (struct cpufreq_policy *policy,
 187                 struct cpufreq_frequency_table *table)
 188 {
 189         unsigned int i, j, count = 0, ret = 0;
 190         struct cpufreq_stats *stat;
 191         struct cpufreq_policy *data;
 192         unsigned int alloc_size;
 193         unsigned int cpu = policy->cpu;
 194         if (cpufreq_stats_table[cpu])
 195                 return -EBUSY;
 196         if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
 197                 return -ENOMEM;
 198
 199         data = cpufreq_cpu_get(cpu);
 200         if (data == NULL) {
 201                 ret = -EINVAL;
 202                 goto error_get_fail;
 203         }
 204
 205         if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 206                 goto error_out;
 207
 208         stat->cpu = cpu;
 209         cpufreq_stats_table[cpu] = stat;
 210
 211         for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 212                 unsigned int freq = table[i].frequency;
 213                 if (freq == CPUFREQ_ENTRY_INVALID)
 214                         continue;
 215                 count++;
 216         }
 217
 218         alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
 219
 220 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 221         alloc_size += count * count * sizeof(int);
 222 #endif
 223         stat->max_state = count;
 224         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 225         if (!stat->time_in_state) {
 226                 ret = -ENOMEM;
 227                 goto error_out;
 228         }
 229         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 230
 231 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 232         stat->trans_table = stat->freq_table + count;
 233 #endif
 234         j = 0;
 235         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 236                 unsigned int freq = table[i].frequency;
 237                 if (freq == CPUFREQ_ENTRY_INVALID)
 238                         continue;
 239                 if (freq_table_get_index(stat, freq) == -1)
 240                         stat->freq_table[j++] = freq;
 241         }
 242         stat->state_num = j;
 243         spin_lock(&cpufreq_stats_lock);
 244         stat->last_time = get_jiffies_64();
 245         stat->last_index = freq_table_get_index(stat, policy->cur);
 246         spin_unlock(&cpufreq_stats_lock);
 247         cpufreq_cpu_put(data);
 248         return 0;
 249 error_out:
 250         cpufreq_cpu_put(data);
 251 error_get_fail:
 252         kfree(stat);
 253         cpufreq_stats_table[cpu] = NULL;
 254         return ret;
 255 }
 256
 257 static int
 258 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 259                 void *data)
 260 {
 261         int ret;
 262         struct cpufreq_policy *policy = data;
 263         struct cpufreq_frequency_table *table;
 264         unsigned int cpu = policy->cpu;
 265         if (val != CPUFREQ_NOTIFY)
 266                 return 0;
 267         table = cpufreq_frequency_get_table(cpu);
 268         if (!table)
 269                 return 0;
 270         if ((ret = cpufreq_stats_create_table(policy, table)))
 271                 return ret;
 272         return 0;
 273 }
 274
 275 static int
 276 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 277                 void *data)
 278 {
 279         struct cpufreq_freqs *freq = data;
 280         struct cpufreq_stats *stat;
 281         int old_index, new_index;
 282
 283         if (val != CPUFREQ_POSTCHANGE)
 284                 return 0;
 285
 286         stat = cpufreq_stats_table[freq->cpu];
 287         if (!stat)
 288                 return 0;
 289         old_index = freq_table_get_index(stat, freq->old);
 290         new_index = freq_table_get_index(stat, freq->new);
 291
 292         cpufreq_stats_update(freq->cpu);
 293         if (old_index == new_index)
 294                 return 0;
 295
 296         spin_lock(&cpufreq_stats_lock);
 297         stat->last_index = new_index;
 298 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 299         stat->trans_table[old_index * stat->max_state + new_index]++;
 300 #endif
 301         stat->total_trans++;
 302         spin_unlock(&cpufreq_stats_lock);
 303         return 0;
 304 }
 305
 306 static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 307                                         unsigned long action, void *hcpu)
 308 {
 309         unsigned int cpu = (unsigned long)hcpu;
 310
 311         switch (action) {
 312         case CPU_ONLINE:
 313                 cpufreq_update_policy(cpu);
 314                 break;
 315         case CPU_DEAD:
 316                 cpufreq_stats_free_table(cpu);
 317                 break;
 318         }
 319         return NOTIFY_OK;
 320 }
 321
 322 static struct notifier_block cpufreq_stat_cpu_notifier =
 323 {
 324         .notifier_call = cpufreq_stat_cpu_callback,
 325 };
 326
 327 static struct notifier_block notifier_policy_block = {
 328         .notifier_call = cpufreq_stat_notifier_policy
 329 };
 330
 331 static struct notifier_block notifier_trans_block = {
 332         .notifier_call = cpufreq_stat_notifier_trans
 333 };
 334
 335 static int
 336 __init cpufreq_stats_init(void)
 337 {
 338         int ret;
 339         unsigned int cpu;
 340
 341         spin_lock_init(&cpufreq_stats_lock);
 342         if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 343                                 CPUFREQ_POLICY_NOTIFIER)))
 344                 return ret;
 345
 346         if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 347                                 CPUFREQ_TRANSITION_NOTIFIER))) {
 348                 cpufreq_unregister_notifier(&notifier_policy_block,
 349                                 CPUFREQ_POLICY_NOTIFIER);
 350                 return ret;
 351         }
 352
 353         register_cpu_notifier(&cpufreq_stat_cpu_notifier);
 354         lock_cpu_hotplug();
 355         for_each_online_cpu(cpu) {
 356                 cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_ONLINE,
 357                         (void *)(long)cpu);
 358         }
 359         unlock_cpu_hotplug();
 360         return 0;
 361 }
 362 static void
 363 __exit cpufreq_stats_exit(void)
 364 {
 365         unsigned int cpu;
 366
 367         cpufreq_unregister_notifier(&notifier_policy_block,
 368                         CPUFREQ_POLICY_NOTIFIER);
 369         cpufreq_unregister_notifier(&notifier_trans_block,
 370                         CPUFREQ_TRANSITION_NOTIFIER);
 371         unregister_cpu_notifier(&cpufreq_stat_cpu_notifier);
 372         lock_cpu_hotplug();
 373         for_each_online_cpu(cpu) {
 374                 cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_DEAD,
 375                         (void *)(long)cpu);
 376         }
 377         unlock_cpu_hotplug();
 378 }
 379
 380 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 381 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
 382 MODULE_LICENSE ("GPL");
 383
 384 module_init(cpufreq_stats_init);
 385 module_exit(cpufreq_stats_exit);