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
  23 static spinlock_t cpufreq_stats_lock;
  24
  25 #define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
  26 static struct freq_attr _attr_##_name = {\
  27         .attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
  28                 .mode = _mode, }, \
  29         .show = _show,\
  30 };
  31
  32 static unsigned long
  33 delta_time(unsigned long old, unsigned long new)
  34 {
  35         return (old > new) ? (old - new): (new + ~old + 1);
  36 }
  37
  38 struct cpufreq_stats {
  39         unsigned int cpu;
  40         unsigned int total_trans;
  41         unsigned long long last_time;
  42         unsigned int max_state;
  43         unsigned int state_num;
  44         unsigned int last_index;
  45         unsigned long long *time_in_state;
  46         unsigned int *freq_table;
  47 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  48         unsigned int *trans_table;
  49 #endif
  50 };
  51
  52 static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
  53
  54 struct cpufreq_stats_attribute {
  55         struct attribute attr;
  56         ssize_t(*show) (struct cpufreq_stats *, char *);
  57 };
  58
  59 static int
  60 cpufreq_stats_update (unsigned int cpu)
  61 {
  62         struct cpufreq_stats *stat;
  63         spin_lock(&cpufreq_stats_lock);
  64         stat = cpufreq_stats_table[cpu];
  65         if (stat->time_in_state)
  66                 stat->time_in_state[stat->last_index] +=
  67                         delta_time(stat->last_time, jiffies);
  68         stat->last_time = jiffies;
  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",
  94                         stat->freq_table[i], 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         for (i = 0; i < stat->state_num; i++) {
 111                 if (len >= PAGE_SIZE)
 112                         break;
 113                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u:\t",
 114                                 stat->freq_table[i]);
 115
 116                 for (j = 0; j < stat->state_num; j++)   {
 117                         if (len >= PAGE_SIZE)
 118                                 break;
 119                         len += snprintf(buf + len, PAGE_SIZE - len, "%u\t",
 120                                         stat->trans_table[i*stat->max_state+j]);
 121                 }
 122                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 123         }
 124         return len;
 125 }
 126 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
 127 #endif
 128
 129 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
 130 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
 131
 132 static struct attribute *default_attrs[] = {
 133         &_attr_total_trans.attr,
 134         &_attr_time_in_state.attr,
 135 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 136         &_attr_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
 146 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 147 {
 148         int index;
 149         for (index = 0; index < stat->max_state; index++)
 150                 if (stat->freq_table[index] == freq)
 151                         return index;
 152         return -1;
 153 }
 154
 155 static void
 156 cpufreq_stats_free_table (unsigned int cpu)
 157 {
 158         struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
 159         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 160         if (policy && policy->cpu == cpu)
 161                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
 162         if (stat) {
 163                 kfree(stat->time_in_state);
 164                 kfree(stat);
 165         }
 166         cpufreq_stats_table[cpu] = NULL;
 167         if (policy)
 168                 cpufreq_cpu_put(policy);
 169 }
 170
 171 static int
 172 cpufreq_stats_create_table (struct cpufreq_policy *policy,
 173                 struct cpufreq_frequency_table *table)
 174 {
 175         unsigned int i, j, count = 0, ret = 0;
 176         struct cpufreq_stats *stat;
 177         struct cpufreq_policy *data;
 178         unsigned int alloc_size;
 179         unsigned int cpu = policy->cpu;
 180         if (cpufreq_stats_table[cpu])
 181                 return -EBUSY;
 182         if ((stat = kmalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
 183                 return -ENOMEM;
 184         memset(stat, 0, sizeof (struct cpufreq_stats));
 185
 186         data = cpufreq_cpu_get(cpu);
 187         if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 188                 goto error_out;
 189
 190         stat->cpu = cpu;
 191         cpufreq_stats_table[cpu] = stat;
 192
 193         for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 194                 unsigned int freq = table[i].frequency;
 195                 if (freq == CPUFREQ_ENTRY_INVALID)
 196                         continue;
 197                 count++;
 198         }
 199
 200         alloc_size = count * sizeof(int) + count * sizeof(long long);
 201
 202 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 203         alloc_size += count * count * sizeof(int);
 204 #endif
 205         stat->max_state = count;
 206         stat->time_in_state = kmalloc(alloc_size, GFP_KERNEL);
 207         if (!stat->time_in_state) {
 208                 ret = -ENOMEM;
 209                 goto error_out;
 210         }
 211         memset(stat->time_in_state, 0, alloc_size);
 212         stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 213
 214 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 215         stat->trans_table = stat->freq_table + count;
 216 #endif
 217         j = 0;
 218         for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 219                 unsigned int freq = table[i].frequency;
 220                 if (freq == CPUFREQ_ENTRY_INVALID)
 221                         continue;
 222                 if (freq_table_get_index(stat, freq) == -1)
 223                         stat->freq_table[j++] = freq;
 224         }
 225         stat->state_num = j;
 226         spin_lock(&cpufreq_stats_lock);
 227         stat->last_time = jiffies;
 228         stat->last_index = freq_table_get_index(stat, policy->cur);
 229         spin_unlock(&cpufreq_stats_lock);
 230         cpufreq_cpu_put(data);
 231         return 0;
 232 error_out:
 233         cpufreq_cpu_put(data);
 234         kfree(stat);
 235         cpufreq_stats_table[cpu] = NULL;
 236         return ret;
 237 }
 238
 239 static int
 240 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 241                 void *data)
 242 {
 243         int ret;
 244         struct cpufreq_policy *policy = data;
 245         struct cpufreq_frequency_table *table;
 246         unsigned int cpu = policy->cpu;
 247         if (val != CPUFREQ_NOTIFY)
 248                 return 0;
 249         table = cpufreq_frequency_get_table(cpu);
 250         if (!table)
 251                 return 0;
 252         if ((ret = cpufreq_stats_create_table(policy, table)))
 253                 return ret;
 254         return 0;
 255 }
 256
 257 static int
 258 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 259                 void *data)
 260 {
 261         struct cpufreq_freqs *freq = data;
 262         struct cpufreq_stats *stat;
 263         int old_index, new_index;
 264
 265         if (val != CPUFREQ_POSTCHANGE)
 266                 return 0;
 267
 268         stat = cpufreq_stats_table[freq->cpu];
 269         if (!stat)
 270                 return 0;
 271         old_index = freq_table_get_index(stat, freq->old);
 272         new_index = freq_table_get_index(stat, freq->new);
 273
 274         cpufreq_stats_update(freq->cpu);
 275         if (old_index == new_index)
 276                 return 0;
 277
 278         spin_lock(&cpufreq_stats_lock);
 279         stat->last_index = new_index;
 280 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 281         stat->trans_table[old_index * stat->max_state + new_index]++;
 282 #endif
 283         stat->total_trans++;
 284         spin_unlock(&cpufreq_stats_lock);
 285         return 0;
 286 }
 287
 288 static struct notifier_block notifier_policy_block = {
 289         .notifier_call = cpufreq_stat_notifier_policy
 290 };
 291
 292 static struct notifier_block notifier_trans_block = {
 293         .notifier_call = cpufreq_stat_notifier_trans
 294 };
 295
 296 static int
 297 __init cpufreq_stats_init(void)
 298 {
 299         int ret;
 300         unsigned int cpu;
 301         spin_lock_init(&cpufreq_stats_lock);
 302         if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 303                                 CPUFREQ_POLICY_NOTIFIER)))
 304                 return ret;
 305
 306         if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 307                                 CPUFREQ_TRANSITION_NOTIFIER))) {
 308                 cpufreq_unregister_notifier(&notifier_policy_block,
 309                                 CPUFREQ_POLICY_NOTIFIER);
 310                 return ret;
 311         }
 312
 313         for_each_cpu(cpu)
 314                 cpufreq_update_policy(cpu);
 315         return 0;
 316 }
 317 static void
 318 __exit cpufreq_stats_exit(void)
 319 {
 320         unsigned int cpu;
 321         cpufreq_unregister_notifier(&notifier_policy_block,
 322                         CPUFREQ_POLICY_NOTIFIER);
 323         cpufreq_unregister_notifier(&notifier_trans_block,
 324                         CPUFREQ_TRANSITION_NOTIFIER);
 325         for_each_cpu(cpu)
 326                 cpufreq_stats_free_table(cpu);
 327 }
 328
 329 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 330 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
 331 MODULE_LICENSE ("GPL");
 332
 333 module_init(cpufreq_stats_init);
 334 module_exit(cpufreq_stats_exit);