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/cpu.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/cputime.h>
  17
  18 static spinlock_t cpufreq_stats_lock;
  19
  20 struct cpufreq_stats {
  21         unsigned int cpu;
  22         unsigned int total_trans;
  23         unsigned long long last_time;
  24         unsigned int max_state;
  25         unsigned int state_num;
  26         unsigned int last_index;
  27         u64 *time_in_state;
  28         unsigned int *freq_table;
  29 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  30         unsigned int *trans_table;
  31 #endif
  32 };
  33
  34 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  35
  36 struct cpufreq_stats_attribute {
  37         struct attribute attr;
  38         ssize_t(*show) (struct cpufreq_stats *, char *);
  39 };
  40
  41 static int cpufreq_stats_update(unsigned int cpu)
  42 {
  43         struct cpufreq_stats *stat;
  44         unsigned long long cur_time;
  45
  46         cur_time = get_jiffies_64();
  47         spin_lock(&cpufreq_stats_lock);
  48         stat = per_cpu(cpufreq_stats_table, cpu);
  49         if (stat->time_in_state)
  50                 stat->time_in_state[stat->last_index] +=
  51                         cur_time - stat->last_time;
  52         stat->last_time = cur_time;
  53         spin_unlock(&cpufreq_stats_lock);
  54         return 0;
  55 }
  56
  57 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  58 {
  59         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  60         if (!stat)
  61                 return 0;
  62         return sprintf(buf, "%d\n",
  63                         per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  64 }
  65
  66 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  67 {
  68         ssize_t len = 0;
  69         int i;
  70         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  71         if (!stat)
  72                 return 0;
  73         cpufreq_stats_update(stat->cpu);
  74         for (i = 0; i < stat->state_num; i++) {
  75                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  76                         (unsigned long long)
  77                         jiffies_64_to_clock_t(stat->time_in_state[i]));
  78         }
  79         return len;
  80 }
  81
  82 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  83 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  84 {
  85         ssize_t len = 0;
  86         int i, j;
  87
  88         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  89         if (!stat)
  90                 return 0;
  91         cpufreq_stats_update(stat->cpu);
  92         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  93         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  94         for (i = 0; i < stat->state_num; i++) {
  95                 if (len >= PAGE_SIZE)
  96                         break;
  97                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  98                                 stat->freq_table[i]);
  99         }
 100         if (len >= PAGE_SIZE)
 101                 return PAGE_SIZE;
 102
 103         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 104
 105         for (i = 0; i < stat->state_num; i++) {
 106                 if (len >= PAGE_SIZE)
 107                         break;
 108
 109                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 110                                 stat->freq_table[i]);
 111
 112                 for (j = 0; j < stat->state_num; j++) {
 113                         if (len >= PAGE_SIZE)
 114                                 break;
 115                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 116                                         stat->trans_table[i*stat->max_state+j]);
 117                 }
 118                 if (len >= PAGE_SIZE)
 119                         break;
 120                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 121         }
 122         if (len >= PAGE_SIZE)
 123                 return PAGE_SIZE;
 124         return len;
 125 }
 126 cpufreq_freq_attr_ro(trans_table);
 127 #endif
 128
 129 cpufreq_freq_attr_ro(total_trans);
 130 cpufreq_freq_attr_ro(time_in_state);
 131
 132 static struct attribute *default_attrs[] = {
 133         &total_trans.attr,
 134         &time_in_state.attr,
 135 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 136         &trans_table.attr,
 137 #endif
 138         NULL
 139 };
 140 static struct attribute_group stats_attr_group = {
 141         .attrs = default_attrs,
 142         .name = "stats"
 143 };
 144
 145 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 146 {
 147         int index;
 148         for (index = 0; index < stat->max_state; index++)
 149                 if (stat->freq_table[index] == freq)
 150                         return index;
 151         return -1;
 152 }
 153
 154 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 155 {
 156         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 157
 158         if (!stat)
 159                 return;
 160
 161         pr_debug("%s: Free stat table\n", __func__);
 162
 163         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 164         kfree(stat->time_in_state);
 165         kfree(stat);
 166         per_cpu(cpufreq_stats_table, policy->cpu) = NULL;
 167 }
 168
 169 static void cpufreq_stats_free_table(unsigned int cpu)
 170 {
 171         struct cpufreq_policy *policy;
 172
 173         policy = cpufreq_cpu_get(cpu);
 174         if (!policy)
 175                 return;
 176
 177         if (cpufreq_frequency_get_table(policy->cpu))
 178                 __cpufreq_stats_free_table(policy);
 179
 180         cpufreq_cpu_put(policy);
 181 }
 182
 183 static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
 184 {
 185         unsigned int i, j, count = 0, ret = 0;
 186         struct cpufreq_stats *stat;
 187         unsigned int alloc_size;
 188         unsigned int cpu = policy->cpu;
 189         struct cpufreq_frequency_table *table;
 190
 191         table = cpufreq_frequency_get_table(cpu);
 192         if (unlikely(!table))
 193                 return 0;
 194
 195         if (per_cpu(cpufreq_stats_table, cpu))
 196                 return -EBUSY;
 197         stat = kzalloc(sizeof(*stat), GFP_KERNEL);
 198         if ((stat) == NULL)
 199                 return -ENOMEM;
 200
 201         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 202         if (ret)
 203                 goto error_out;
 204
 205         stat->cpu = cpu;
 206         per_cpu(cpufreq_stats_table, cpu) = stat;
 207
 208         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 209                 unsigned int freq = table[i].frequency;
 210                 if (freq == CPUFREQ_ENTRY_INVALID)
 211                         continue;
 212                 count++;
 213         }
 214
 215         alloc_size = count * sizeof(int) + count * sizeof(u64);
 216
 217 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 218         alloc_size += count * count * sizeof(int);
 219 #endif
 220         stat->max_state = count;
 221         stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 222         if (!stat->time_in_state) {
 223                 ret = -ENOMEM;
 224                 goto error_alloc;
 225         }
 226         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 227
 228 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 229         stat->trans_table = stat->freq_table + count;
 230 #endif
 231         j = 0;
 232         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 233                 unsigned int freq = table[i].frequency;
 234                 if (freq == CPUFREQ_ENTRY_INVALID)
 235                         continue;
 236                 if (freq_table_get_index(stat, freq) == -1)
 237                         stat->freq_table[j++] = freq;
 238         }
 239         stat->state_num = j;
 240         spin_lock(&cpufreq_stats_lock);
 241         stat->last_time = get_jiffies_64();
 242         stat->last_index = freq_table_get_index(stat, policy->cur);
 243         spin_unlock(&cpufreq_stats_lock);
 244         return 0;
 245 error_alloc:
 246         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 247 error_out:
 248         kfree(stat);
 249         per_cpu(cpufreq_stats_table, cpu) = NULL;
 250         return ret;
 251 }
 252
 253 static void cpufreq_stats_create_table(unsigned int cpu)
 254 {
 255         struct cpufreq_policy *policy;
 256
 257         /*
 258          * "likely(!policy)" because normally cpufreq_stats will be registered
 259          * before cpufreq driver
 260          */
 261         policy = cpufreq_cpu_get(cpu);
 262         if (likely(!policy))
 263                 return;
 264
 265         __cpufreq_stats_create_table(policy);
 266
 267         cpufreq_cpu_put(policy);
 268 }
 269
 270 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 271 {
 272         struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
 273                         policy->last_cpu);
 274
 275         pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
 276                         policy->cpu, policy->last_cpu);
 277         per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
 278                         policy->last_cpu);
 279         per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
 280         stat->cpu = policy->cpu;
 281 }
 282
 283 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 284                 unsigned long val, void *data)
 285 {
 286         int ret = 0;
 287         struct cpufreq_policy *policy = data;
 288
 289         if (val == CPUFREQ_UPDATE_POLICY_CPU) {
 290                 cpufreq_stats_update_policy_cpu(policy);
 291                 return 0;
 292         }
 293
 294         if (val == CPUFREQ_CREATE_POLICY)
 295                 ret = __cpufreq_stats_create_table(policy);
 296         else if (val == CPUFREQ_REMOVE_POLICY)
 297                 __cpufreq_stats_free_table(policy);
 298
 299         return ret;
 300 }
 301
 302 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 303                 unsigned long val, void *data)
 304 {
 305         struct cpufreq_freqs *freq = data;
 306         struct cpufreq_stats *stat;
 307         int old_index, new_index;
 308
 309         if (val != CPUFREQ_POSTCHANGE)
 310                 return 0;
 311
 312         stat = per_cpu(cpufreq_stats_table, freq->cpu);
 313         if (!stat)
 314                 return 0;
 315
 316         old_index = stat->last_index;
 317         new_index = freq_table_get_index(stat, freq->new);
 318
 319         /* We can't do stat->time_in_state[-1]= .. */
 320         if (old_index == -1 || new_index == -1)
 321                 return 0;
 322
 323         cpufreq_stats_update(freq->cpu);
 324
 325         if (old_index == new_index)
 326                 return 0;
 327
 328         spin_lock(&cpufreq_stats_lock);
 329         stat->last_index = new_index;
 330 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 331         stat->trans_table[old_index * stat->max_state + new_index]++;
 332 #endif
 333         stat->total_trans++;
 334         spin_unlock(&cpufreq_stats_lock);
 335         return 0;
 336 }
 337
 338 static struct notifier_block notifier_policy_block = {
 339         .notifier_call = cpufreq_stat_notifier_policy
 340 };
 341
 342 static struct notifier_block notifier_trans_block = {
 343         .notifier_call = cpufreq_stat_notifier_trans
 344 };
 345
 346 static int __init cpufreq_stats_init(void)
 347 {
 348         int ret;
 349         unsigned int cpu;
 350
 351         spin_lock_init(&cpufreq_stats_lock);
 352         ret = cpufreq_register_notifier(&notifier_policy_block,
 353                                 CPUFREQ_POLICY_NOTIFIER);
 354         if (ret)
 355                 return ret;
 356
 357         for_each_online_cpu(cpu)
 358                 cpufreq_stats_create_table(cpu);
 359
 360         ret = cpufreq_register_notifier(&notifier_trans_block,
 361                                 CPUFREQ_TRANSITION_NOTIFIER);
 362         if (ret) {
 363                 cpufreq_unregister_notifier(&notifier_policy_block,
 364                                 CPUFREQ_POLICY_NOTIFIER);
 365                 for_each_online_cpu(cpu)
 366                         cpufreq_stats_free_table(cpu);
 367                 return ret;
 368         }
 369
 370         return 0;
 371 }
 372 static void __exit cpufreq_stats_exit(void)
 373 {
 374         unsigned int cpu;
 375
 376         cpufreq_unregister_notifier(&notifier_policy_block,
 377                         CPUFREQ_POLICY_NOTIFIER);
 378         cpufreq_unregister_notifier(&notifier_trans_block,
 379                         CPUFREQ_TRANSITION_NOTIFIER);
 380         for_each_online_cpu(cpu)
 381                 cpufreq_stats_free_table(cpu);
 382 }
 383
 384 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
 385 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
 386                                 "through sysfs filesystem");
 387 MODULE_LICENSE("GPL");
 388
 389 module_init(cpufreq_stats_init);
 390 module_exit(cpufreq_stats_exit);