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