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), .owner = THIS_MODULE, \
  29                 .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 struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
  48
  49 struct cpufreq_stats_attribute {
  50         struct attribute attr;
  51         ssize_t(*show) (struct cpufreq_stats *, char *);
  52 };
  53
  54 static int
  55 cpufreq_stats_update (unsigned int cpu)
  56 {
  57         struct cpufreq_stats *stat;
  58         unsigned long long cur_time;
  59
  60         cur_time = get_jiffies_64();
  61         spin_lock(&cpufreq_stats_lock);
  62         stat = cpufreq_stats_table[cpu];
  63         if (stat->time_in_state)
  64                 stat->time_in_state[stat->last_index] =
  65                         cputime64_add(stat->time_in_state[stat->last_index],
  66                                       cputime_sub(cur_time, stat->last_time));
  67         stat->last_time = cur_time;
  68         spin_unlock(&cpufreq_stats_lock);
  69         return 0;
  70 }
  71
  72 static ssize_t
  73 show_total_trans(struct cpufreq_policy *policy, char *buf)
  74 {
  75         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  76         if (!stat)
  77                 return 0;
  78         return sprintf(buf, "%d\n",
  79                         cpufreq_stats_table[stat->cpu]->total_trans);
  80 }
  81
  82 static ssize_t
  83 show_time_in_state(struct cpufreq_policy *policy, char *buf)
  84 {
  85         ssize_t len = 0;
  86         int i;
  87         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
  88         if (!stat)
  89                 return 0;
  90         cpufreq_stats_update(stat->cpu);
  91         for (i = 0; i < stat->state_num; i++) {
  92                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  93                         (unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
  94         }
  95         return len;
  96 }
  97
  98 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  99 static ssize_t
 100 show_trans_table(struct cpufreq_policy *policy, char *buf)
 101 {
 102         ssize_t len = 0;
 103         int i, j;
 104
 105         struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
 106         if (!stat)
 107                 return 0;
 108         cpufreq_stats_update(stat->cpu);
 109         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 110         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 111         for (i = 0; i < stat->state_num; i++) {
 112                 if (len >= PAGE_SIZE)
 113                         break;
 114                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 115                                 stat->freq_table[i]);
 116         }
 117         if (len >= PAGE_SIZE)
 118                 return len;
 119
 120         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 121
 122         for (i = 0; i < stat->state_num; i++) {
 123                 if (len >= PAGE_SIZE)
 124                         break;
 125
 126                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 127                                 stat->freq_table[i]);
 128
 129                 for (j = 0; j < stat->state_num; j++)   {
 130                         if (len >= PAGE_SIZE)
 131                                 break;
 132                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 133                                         stat->trans_table[i*stat->max_state+j]);
 134                 }
 135                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 136         }
 137         return len;
 138 }
 139 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
 140 #endif
 141
 142 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
 143 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
 144
 145 static struct attribute *default_attrs[] = {
 146         &_attr_total_trans.attr,
 147         &_attr_time_in_state.attr,
 148 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 149         &_attr_trans_table.attr,
 150 #endif
 151         NULL
 152 };
 153 static struct attribute_group stats_attr_group = {
 154         .attrs = default_attrs,
 155         .name = "stats"
 156 };
 157
 158 static int
 159 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
 169 cpufreq_stats_free_table (unsigned int cpu)
 170 {
 171         struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
 172         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 173         if (policy && policy->cpu == cpu)
 174                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 175         if (stat) {
 176                 kfree(stat->time_in_state);
 177                 kfree(stat);
 178         }
 179         cpufreq_stats_table[cpu] = NULL;
 180         if (policy)
 181                 cpufreq_cpu_put(policy);
 182 }
 183
 184 static int
 185 cpufreq_stats_create_table (struct cpufreq_policy *policy,
 186                 struct cpufreq_frequency_table *table)
 187 {
 188         unsigned int i, j, count = 0, ret = 0;
 189         struct cpufreq_stats *stat;
 190         struct cpufreq_policy *data;
 191         unsigned int alloc_size;
 192         unsigned int cpu = policy->cpu;
 193         if (cpufreq_stats_table[cpu])
 194                 return -EBUSY;
 195         if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
 196                 return -ENOMEM;
 197
 198         data = cpufreq_cpu_get(cpu);
 199         if (data == NULL) {
 200                 ret = -EINVAL;
 201                 goto error_get_fail;
 202         }
 203
 204         if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 205                 goto error_out;
 206
 207         stat->cpu = cpu;
 208         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         cpufreq_stats_table[cpu] = NULL;
 253         return ret;
 254 }
 255
 256 static int
 257 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 258                 void *data)
 259 {
 260         int ret;
 261         struct cpufreq_policy *policy = data;
 262         struct cpufreq_frequency_table *table;
 263         unsigned int cpu = policy->cpu;
 264         if (val != CPUFREQ_NOTIFY)
 265                 return 0;
 266         table = cpufreq_frequency_get_table(cpu);
 267         if (!table)
 268                 return 0;
 269         if ((ret = cpufreq_stats_create_table(policy, table)))
 270                 return ret;
 271         return 0;
 272 }
 273
 274 static int
 275 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 276                 void *data)
 277 {
 278         struct cpufreq_freqs *freq = data;
 279         struct cpufreq_stats *stat;
 280         int old_index, new_index;
 281
 282         if (val != CPUFREQ_POSTCHANGE)
 283                 return 0;
 284
 285         stat = cpufreq_stats_table[freq->cpu];
 286         if (!stat)
 287                 return 0;
 288
 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         if (old_index == -1 || new_index == -1)
 297                 return 0;
 298
 299         spin_lock(&cpufreq_stats_lock);
 300         stat->last_index = new_index;
 301 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 302         stat->trans_table[old_index * stat->max_state + new_index]++;
 303 #endif
 304         stat->total_trans++;
 305         spin_unlock(&cpufreq_stats_lock);
 306         return 0;
 307 }
 308
 309 static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 310                                         unsigned long action, void *hcpu)
 311 {
 312         unsigned int cpu = (unsigned long)hcpu;
 313
 314         switch (action) {
 315         case CPU_ONLINE:
 316                 cpufreq_update_policy(cpu);
 317                 break;
 318         case CPU_DEAD:
 319                 cpufreq_stats_free_table(cpu);
 320                 break;
 321         }
 322         return NOTIFY_OK;
 323 }
 324
 325 static struct notifier_block cpufreq_stat_cpu_notifier =
 326 {
 327         .notifier_call = cpufreq_stat_cpu_callback,
 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
 339 __init cpufreq_stats_init(void)
 340 {
 341         int ret;
 342         unsigned int cpu;
 343
 344         spin_lock_init(&cpufreq_stats_lock);
 345         if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 346                                 CPUFREQ_POLICY_NOTIFIER)))
 347                 return ret;
 348
 349         if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 350                                 CPUFREQ_TRANSITION_NOTIFIER))) {
 351                 cpufreq_unregister_notifier(&notifier_policy_block,
 352                                 CPUFREQ_POLICY_NOTIFIER);
 353                 return ret;
 354         }
 355
 356         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 357         for_each_online_cpu(cpu) {
 358                 cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
 359                                 CPU_ONLINE, (void *)(long)cpu);
 360         }
 361         return 0;
 362 }
 363 static void
 364 __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         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 373         lock_cpu_hotplug();
 374         for_each_online_cpu(cpu) {
 375                 cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
 376                                                 CPU_DEAD, (void *)(long)cpu);
 377         }
 378         unlock_cpu_hotplug();
 379 }
 380
 381 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 382 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats"
 383                                 "through sysfs filesystem");
 384 MODULE_LICENSE ("GPL");
 385
 386 module_init(cpufreq_stats_init);
 387 module_exit(cpufreq_stats_exit);