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 DEFINE_SPINLOCK(cpufreq_stats_lock);
  19
  20 struct cpufreq_stats {
  21         unsigned int total_trans;
  22         unsigned long long last_time;
  23         unsigned int max_state;
  24         unsigned int state_num;
  25         unsigned int last_index;
  26         u64 *time_in_state;
  27         unsigned int *freq_table;
  28 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  29         unsigned int *trans_table;
  30 #endif
  31 };
  32
  33 static int cpufreq_stats_update(struct cpufreq_stats *stats)
  34 {
  35         unsigned long long cur_time = get_jiffies_64();
  36
  37         spin_lock(&cpufreq_stats_lock);
  38         stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
  39         stats->last_time = cur_time;
  40         spin_unlock(&cpufreq_stats_lock);
  41         return 0;
  42 }
  43
  44 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  45 {
  46         return sprintf(buf, "%d\n", policy->stats->total_trans);
  47 }
  48
  49 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  50 {
  51         struct cpufreq_stats *stats = policy->stats;
  52         ssize_t len = 0;
  53         int i;
  54
  55         if (policy->fast_switch_enabled)
  56                 return 0;
  57
  58         cpufreq_stats_update(stats);
  59         for (i = 0; i < stats->state_num; i++) {
  60                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  61                         (unsigned long long)
  62                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  63         }
  64         return len;
  65 }
  66
  67 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  68 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  69 {
  70         struct cpufreq_stats *stats = policy->stats;
  71         ssize_t len = 0;
  72         int i, j;
  73
  74         if (policy->fast_switch_enabled)
  75                 return 0;
  76
  77         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  78         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  79         for (i = 0; i < stats->state_num; i++) {
  80                 if (len >= PAGE_SIZE)
  81                         break;
  82                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
  83                                 stats->freq_table[i]);
  84         }
  85         if (len >= PAGE_SIZE)
  86                 return PAGE_SIZE;
  87
  88         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
  89
  90         for (i = 0; i < stats->state_num; i++) {
  91                 if (len >= PAGE_SIZE)
  92                         break;
  93
  94                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
  95                                 stats->freq_table[i]);
  96
  97                 for (j = 0; j < stats->state_num; j++) {
  98                         if (len >= PAGE_SIZE)
  99                                 break;
 100                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 101                                         stats->trans_table[i*stats->max_state+j]);
 102                 }
 103                 if (len >= PAGE_SIZE)
 104                         break;
 105                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 106         }
 107         if (len >= PAGE_SIZE)
 108                 return PAGE_SIZE;
 109         return len;
 110 }
 111 cpufreq_freq_attr_ro(trans_table);
 112 #endif
 113
 114 cpufreq_freq_attr_ro(total_trans);
 115 cpufreq_freq_attr_ro(time_in_state);
 116
 117 static struct attribute *default_attrs[] = {
 118         &total_trans.attr,
 119         &time_in_state.attr,
 120 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 121         &trans_table.attr,
 122 #endif
 123         NULL
 124 };
 125 static struct attribute_group stats_attr_group = {
 126         .attrs = default_attrs,
 127         .name = "stats"
 128 };
 129
 130 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 131 {
 132         int index;
 133         for (index = 0; index < stats->max_state; index++)
 134                 if (stats->freq_table[index] == freq)
 135                         return index;
 136         return -1;
 137 }
 138
 139 void cpufreq_stats_free_table(struct cpufreq_policy *policy)
 140 {
 141         struct cpufreq_stats *stats = policy->stats;
 142
 143         /* Already freed */
 144         if (!stats)
 145                 return;
 146
 147         pr_debug("%s: Free stats table\n", __func__);
 148
 149         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 150         kfree(stats->time_in_state);
 151         kfree(stats);
 152         policy->stats = NULL;
 153 }
 154
 155 void cpufreq_stats_create_table(struct cpufreq_policy *policy)
 156 {
 157         unsigned int i = 0, count = 0, ret = -ENOMEM;
 158         struct cpufreq_stats *stats;
 159         unsigned int alloc_size;
 160         struct cpufreq_frequency_table *pos, *table;
 161
 162         /* We need cpufreq table for creating stats table */
 163         table = policy->freq_table;
 164         if (unlikely(!table))
 165                 return;
 166
 167         /* stats already initialized */
 168         if (policy->stats)
 169                 return;
 170
 171         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 172         if (!stats)
 173                 return;
 174
 175         /* Find total allocation size */
 176         cpufreq_for_each_valid_entry(pos, table)
 177                 count++;
 178
 179         alloc_size = count * sizeof(int) + count * sizeof(u64);
 180
 181 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 182         alloc_size += count * count * sizeof(int);
 183 #endif
 184
 185         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 186         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 187         if (!stats->time_in_state)
 188                 goto free_stat;
 189
 190         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 191
 192 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 193         stats->trans_table = stats->freq_table + count;
 194 #endif
 195
 196         stats->max_state = count;
 197
 198         /* Find valid-unique entries */
 199         cpufreq_for_each_valid_entry(pos, table)
 200                 if (freq_table_get_index(stats, pos->frequency) == -1)
 201                         stats->freq_table[i++] = pos->frequency;
 202
 203         stats->state_num = i;
 204         stats->last_time = get_jiffies_64();
 205         stats->last_index = freq_table_get_index(stats, policy->cur);
 206
 207         policy->stats = stats;
 208         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 209         if (!ret)
 210                 return;
 211
 212         /* We failed, release resources */
 213         policy->stats = NULL;
 214         kfree(stats->time_in_state);
 215 free_stat:
 216         kfree(stats);
 217 }
 218
 219 void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
 220                                      unsigned int new_freq)
 221 {
 222         struct cpufreq_stats *stats = policy->stats;
 223         int old_index, new_index;
 224
 225         if (!stats) {
 226                 pr_debug("%s: No stats found\n", __func__);
 227                 return;
 228         }
 229
 230         old_index = stats->last_index;
 231         new_index = freq_table_get_index(stats, new_freq);
 232
 233         /* We can't do stats->time_in_state[-1]= .. */
 234         if (old_index == -1 || new_index == -1 || old_index == new_index)
 235                 return;
 236
 237         cpufreq_stats_update(stats);
 238
 239         stats->last_index = new_index;
 240 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 241         stats->trans_table[old_index * stats->max_state + new_index]++;
 242 #endif
 243         stats->total_trans++;
 244 }