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
  17 static DEFINE_SPINLOCK(cpufreq_stats_lock);
  18
  19 struct cpufreq_stats {
  20         unsigned int total_trans;
  21         unsigned long long last_time;
  22         unsigned int max_state;
  23         unsigned int state_num;
  24         unsigned int last_index;
  25         u64 *time_in_state;
  26         unsigned int *freq_table;
  27 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  28         unsigned int *trans_table;
  29 #endif
  30 };
  31
  32 static int cpufreq_stats_update(struct cpufreq_stats *stats)
  33 {
  34         unsigned long long cur_time = get_jiffies_64();
  35
  36         spin_lock(&cpufreq_stats_lock);
  37         stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
  38         stats->last_time = cur_time;
  39         spin_unlock(&cpufreq_stats_lock);
  40         return 0;
  41 }
  42
  43 static void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
  44 {
  45         unsigned int count = stats->max_state;
  46
  47         memset(stats->time_in_state, 0, count * sizeof(u64));
  48 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  49         memset(stats->trans_table, 0, count * count * sizeof(int));
  50 #endif
  51         stats->last_time = get_jiffies_64();
  52         stats->total_trans = 0;
  53 }
  54
  55 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  56 {
  57         return sprintf(buf, "%d\n", policy->stats->total_trans);
  58 }
  59
  60 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  61 {
  62         struct cpufreq_stats *stats = policy->stats;
  63         ssize_t len = 0;
  64         int i;
  65
  66         if (policy->fast_switch_enabled)
  67                 return 0;
  68
  69         cpufreq_stats_update(stats);
  70         for (i = 0; i < stats->state_num; i++) {
  71                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  72                         (unsigned long long)
  73                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  74         }
  75         return len;
  76 }
  77
  78 static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
  79                            size_t count)
  80 {
  81         /* We don't care what is written to the attribute. */
  82         cpufreq_stats_clear_table(policy->stats);
  83         return count;
  84 }
  85
  86 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  87 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  88 {
  89         struct cpufreq_stats *stats = policy->stats;
  90         ssize_t len = 0;
  91         int i, j;
  92
  93         if (policy->fast_switch_enabled)
  94                 return 0;
  95
  96         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  97         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  98         for (i = 0; i < stats->state_num; i++) {
  99                 if (len >= PAGE_SIZE)
 100                         break;
 101                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 102                                 stats->freq_table[i]);
 103         }
 104         if (len >= PAGE_SIZE)
 105                 return PAGE_SIZE;
 106
 107         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 108
 109         for (i = 0; i < stats->state_num; i++) {
 110                 if (len >= PAGE_SIZE)
 111                         break;
 112
 113                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 114                                 stats->freq_table[i]);
 115
 116                 for (j = 0; j < stats->state_num; j++) {
 117                         if (len >= PAGE_SIZE)
 118                                 break;
 119                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 120                                         stats->trans_table[i*stats->max_state+j]);
 121                 }
 122                 if (len >= PAGE_SIZE)
 123                         break;
 124                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 125         }
 126         if (len >= PAGE_SIZE)
 127                 return PAGE_SIZE;
 128         return len;
 129 }
 130 cpufreq_freq_attr_ro(trans_table);
 131 #endif
 132
 133 cpufreq_freq_attr_ro(total_trans);
 134 cpufreq_freq_attr_ro(time_in_state);
 135 cpufreq_freq_attr_wo(reset);
 136
 137 static struct attribute *default_attrs[] = {
 138         &total_trans.attr,
 139         &time_in_state.attr,
 140         &reset.attr,
 141 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 142         &trans_table.attr,
 143 #endif
 144         NULL
 145 };
 146 static struct attribute_group stats_attr_group = {
 147         .attrs = default_attrs,
 148         .name = "stats"
 149 };
 150
 151 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 152 {
 153         int index;
 154         for (index = 0; index < stats->max_state; index++)
 155                 if (stats->freq_table[index] == freq)
 156                         return index;
 157         return -1;
 158 }
 159
 160 void cpufreq_stats_free_table(struct cpufreq_policy *policy)
 161 {
 162         struct cpufreq_stats *stats = policy->stats;
 163
 164         /* Already freed */
 165         if (!stats)
 166                 return;
 167
 168         pr_debug("%s: Free stats table\n", __func__);
 169
 170         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 171         kfree(stats->time_in_state);
 172         kfree(stats);
 173         policy->stats = NULL;
 174 }
 175
 176 void cpufreq_stats_create_table(struct cpufreq_policy *policy)
 177 {
 178         unsigned int i = 0, count = 0, ret = -ENOMEM;
 179         struct cpufreq_stats *stats;
 180         unsigned int alloc_size;
 181         struct cpufreq_frequency_table *pos, *table;
 182
 183         /* We need cpufreq table for creating stats table */
 184         table = policy->freq_table;
 185         if (unlikely(!table))
 186                 return;
 187
 188         /* stats already initialized */
 189         if (policy->stats)
 190                 return;
 191
 192         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 193         if (!stats)
 194                 return;
 195
 196         /* Find total allocation size */
 197         cpufreq_for_each_valid_entry(pos, table)
 198                 count++;
 199
 200         alloc_size = count * sizeof(int) + count * sizeof(u64);
 201
 202 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 203         alloc_size += count * count * sizeof(int);
 204 #endif
 205
 206         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 207         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 208         if (!stats->time_in_state)
 209                 goto free_stat;
 210
 211         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 212
 213 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 214         stats->trans_table = stats->freq_table + count;
 215 #endif
 216
 217         stats->max_state = count;
 218
 219         /* Find valid-unique entries */
 220         cpufreq_for_each_valid_entry(pos, table)
 221                 if (freq_table_get_index(stats, pos->frequency) == -1)
 222                         stats->freq_table[i++] = pos->frequency;
 223
 224         stats->state_num = i;
 225         stats->last_time = get_jiffies_64();
 226         stats->last_index = freq_table_get_index(stats, policy->cur);
 227
 228         policy->stats = stats;
 229         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 230         if (!ret)
 231                 return;
 232
 233         /* We failed, release resources */
 234         policy->stats = NULL;
 235         kfree(stats->time_in_state);
 236 free_stat:
 237         kfree(stats);
 238 }
 239
 240 void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
 241                                      unsigned int new_freq)
 242 {
 243         struct cpufreq_stats *stats = policy->stats;
 244         int old_index, new_index;
 245
 246         if (!stats) {
 247                 pr_debug("%s: No stats found\n", __func__);
 248                 return;
 249         }
 250
 251         old_index = stats->last_index;
 252         new_index = freq_table_get_index(stats, new_freq);
 253
 254         /* We can't do stats->time_in_state[-1]= .. */
 255         if (old_index == -1 || new_index == -1 || old_index == new_index)
 256                 return;
 257
 258         cpufreq_stats_update(stats);
 259
 260         stats->last_index = new_index;
 261 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 262         stats->trans_table[old_index * stats->max_state + new_index]++;
 263 #endif
 264         stats->total_trans++;
 265 }