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