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 DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  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 = 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
  72 show_total_trans(struct cpufreq_policy *policy, char *buf)
  73 {
  74         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  75         if (!stat)
  76                 return 0;
  77         return sprintf(buf, "%d\n",
  78                         per_cpu(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 = per_cpu(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 = per_cpu(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 PAGE_SIZE;
 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                 if (len >= PAGE_SIZE)
 135                         break;
 136                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 137         }
 138         if (len >= PAGE_SIZE)
 139                 return PAGE_SIZE;
 140         return len;
 141 }
 142 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
 143 #endif
 144
 145 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
 146 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
 147
 148 static struct attribute *default_attrs[] = {
 149         &_attr_total_trans.attr,
 150         &_attr_time_in_state.attr,
 151 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 152         &_attr_trans_table.attr,
 153 #endif
 154         NULL
 155 };
 156 static struct attribute_group stats_attr_group = {
 157         .attrs = default_attrs,
 158         .name = "stats"
 159 };
 160
 161 static int
 162 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 163 {
 164         int index;
 165         for (index = 0; index < stat->max_state; index++)
 166                 if (stat->freq_table[index] == freq)
 167                         return index;
 168         return -1;
 169 }
 170
 171 static void cpufreq_stats_free_table(unsigned int cpu)
 172 {
 173         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 174         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 175         if (policy && policy->cpu == cpu)
 176                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 177         if (stat) {
 178                 kfree(stat->time_in_state);
 179                 kfree(stat);
 180         }
 181         per_cpu(cpufreq_stats_table, cpu) = NULL;
 182         if (policy)
 183                 cpufreq_cpu_put(policy);
 184 }
 185
 186 static int
 187 cpufreq_stats_create_table (struct cpufreq_policy *policy,
 188                 struct cpufreq_frequency_table *table)
 189 {
 190         unsigned int i, j, count = 0, ret = 0;
 191         struct cpufreq_stats *stat;
 192         struct cpufreq_policy *data;
 193         unsigned int alloc_size;
 194         unsigned int cpu = policy->cpu;
 195         if (per_cpu(cpufreq_stats_table, cpu))
 196                 return -EBUSY;
 197         if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
 198                 return -ENOMEM;
 199
 200         data = cpufreq_cpu_get(cpu);
 201         if (data == NULL) {
 202                 ret = -EINVAL;
 203                 goto error_get_fail;
 204         }
 205
 206         if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 207                 goto error_out;
 208
 209         stat->cpu = cpu;
 210         per_cpu(cpufreq_stats_table, cpu) = stat;
 211
 212         for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 213                 unsigned int freq = table[i].frequency;
 214                 if (freq == CPUFREQ_ENTRY_INVALID)
 215                         continue;
 216                 count++;
 217         }
 218
 219         alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
 220
 221 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 222         alloc_size += count * count * sizeof(int);
 223 #endif
 224         stat->max_state = count;
 225         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 226         if (!stat->time_in_state) {
 227                 ret = -ENOMEM;
 228                 goto error_out;
 229         }
 230         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 231
 232 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 233         stat->trans_table = stat->freq_table + count;
 234 #endif
 235         j = 0;
 236         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 237                 unsigned int freq = table[i].frequency;
 238                 if (freq == CPUFREQ_ENTRY_INVALID)
 239                         continue;
 240                 if (freq_table_get_index(stat, freq) == -1)
 241                         stat->freq_table[j++] = freq;
 242         }
 243         stat->state_num = j;
 244         spin_lock(&cpufreq_stats_lock);
 245         stat->last_time = get_jiffies_64();
 246         stat->last_index = freq_table_get_index(stat, policy->cur);
 247         spin_unlock(&cpufreq_stats_lock);
 248         cpufreq_cpu_put(data);
 249         return 0;
 250 error_out:
 251         cpufreq_cpu_put(data);
 252 error_get_fail:
 253         kfree(stat);
 254         per_cpu(cpufreq_stats_table, cpu) = NULL;
 255         return ret;
 256 }
 257
 258 static int
 259 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 260                 void *data)
 261 {
 262         int ret;
 263         struct cpufreq_policy *policy = data;
 264         struct cpufreq_frequency_table *table;
 265         unsigned int cpu = policy->cpu;
 266         if (val != CPUFREQ_NOTIFY)
 267                 return 0;
 268         table = cpufreq_frequency_get_table(cpu);
 269         if (!table)
 270                 return 0;
 271         if ((ret = cpufreq_stats_create_table(policy, table)))
 272                 return ret;
 273         return 0;
 274 }
 275
 276 static int
 277 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 278                 void *data)
 279 {
 280         struct cpufreq_freqs *freq = data;
 281         struct cpufreq_stats *stat;
 282         int old_index, new_index;
 283
 284         if (val != CPUFREQ_POSTCHANGE)
 285                 return 0;
 286
 287         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 288         if (!stat)
 289                 return 0;
 290
 291         old_index = stat->last_index;
 292         new_index = freq_table_get_index(stat, freq->new);
 293
 294         cpufreq_stats_update(freq->cpu);
 295         if (old_index == new_index)
 296                 return 0;
 297
 298         if (old_index == -1 || new_index == -1)
 299                 return 0;
 300
 301         spin_lock(&cpufreq_stats_lock);
 302         stat->last_index = new_index;
 303 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 304         stat->trans_table[old_index * stat->max_state + new_index]++;
 305 #endif
 306         stat->total_trans++;
 307         spin_unlock(&cpufreq_stats_lock);
 308         return 0;
 309 }
 310
 311 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 312                                                unsigned long action,
 313                                                void *hcpu)
 314 {
 315         unsigned int cpu = (unsigned long)hcpu;
 316
 317         switch (action) {
 318         case CPU_ONLINE:
 319         case CPU_ONLINE_FROZEN:
 320                 cpufreq_update_policy(cpu);
 321                 break;
 322         case CPU_DEAD:
 323         case CPU_DEAD_FROZEN:
 324                 cpufreq_stats_free_table(cpu);
 325                 break;
 326         }
 327         return NOTIFY_OK;
 328 }
 329
 330 static struct notifier_block cpufreq_stat_cpu_notifier __refdata =
 331 {
 332         .notifier_call = cpufreq_stat_cpu_callback,
 333 };
 334
 335 static struct notifier_block notifier_policy_block = {
 336         .notifier_call = cpufreq_stat_notifier_policy
 337 };
 338
 339 static struct notifier_block notifier_trans_block = {
 340         .notifier_call = cpufreq_stat_notifier_trans
 341 };
 342
 343 static int
 344 __init cpufreq_stats_init(void)
 345 {
 346         int ret;
 347         unsigned int cpu;
 348
 349         spin_lock_init(&cpufreq_stats_lock);
 350         if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 351                                 CPUFREQ_POLICY_NOTIFIER)))
 352                 return ret;
 353
 354         if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 355                                 CPUFREQ_TRANSITION_NOTIFIER))) {
 356                 cpufreq_unregister_notifier(&notifier_policy_block,
 357                                 CPUFREQ_POLICY_NOTIFIER);
 358                 return ret;
 359         }
 360
 361         register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 362         for_each_online_cpu(cpu) {
 363                 cpufreq_update_policy(cpu);
 364         }
 365         return 0;
 366 }
 367 static void
 368 __exit cpufreq_stats_exit(void)
 369 {
 370         unsigned int cpu;
 371
 372         cpufreq_unregister_notifier(&notifier_policy_block,
 373                         CPUFREQ_POLICY_NOTIFIER);
 374         cpufreq_unregister_notifier(&notifier_trans_block,
 375                         CPUFREQ_TRANSITION_NOTIFIER);
 376         unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 377         for_each_online_cpu(cpu) {
 378                 cpufreq_stats_free_table(cpu);
 379         }
 380 }
 381
 382 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 383 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats "
 384                                 "through sysfs filesystem");
 385 MODULE_LICENSE ("GPL");
 386
 387 module_init(cpufreq_stats_init);
 388 module_exit(cpufreq_stats_exit);