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 void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
  45 {
  46         unsigned int count = stats->max_state;
  47
  48         memset(stats->time_in_state, 0, count * sizeof(u64));
  49 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  50         memset(stats->trans_table, 0, count * count * sizeof(int));
  51 #endif
  52         stats->last_time = get_jiffies_64();
  53         stats->total_trans = 0;
  54 }
  55
  56 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
  57 {
  58         return sprintf(buf, "%d\n", policy->stats->total_trans);
  59 }
  60
  61 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
  62 {
  63         struct cpufreq_stats *stats = policy->stats;
  64         ssize_t len = 0;
  65         int i;
  66
  67         if (policy->fast_switch_enabled)
  68                 return 0;
  69
  70         cpufreq_stats_update(stats);
  71         for (i = 0; i < stats->state_num; i++) {
  72                 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
  73                         (unsigned long long)
  74                         jiffies_64_to_clock_t(stats->time_in_state[i]));
  75         }
  76         return len;
  77 }
  78
  79 static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
  80                            size_t count)
  81 {
  82         /* We don't care what is written to the attribute. */
  83         cpufreq_stats_clear_table(policy->stats);
  84         return count;
  85 }
  86
  87 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  88 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
  89 {
  90         struct cpufreq_stats *stats = policy->stats;
  91         ssize_t len = 0;
  92         int i, j;
  93
  94         if (policy->fast_switch_enabled)
  95                 return 0;
  96
  97         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
  98         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
  99         for (i = 0; i < stats->state_num; i++) {
 100                 if (len >= PAGE_SIZE)
 101                         break;
 102                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 103                                 stats->freq_table[i]);
 104         }
 105         if (len >= PAGE_SIZE)
 106                 return PAGE_SIZE;
 107
 108         len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 109
 110         for (i = 0; i < stats->state_num; i++) {
 111                 if (len >= PAGE_SIZE)
 112                         break;
 113
 114                 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 115                                 stats->freq_table[i]);
 116
 117                 for (j = 0; j < stats->state_num; j++) {
 118                         if (len >= PAGE_SIZE)
 119                                 break;
 120                         len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 121                                         stats->trans_table[i*stats->max_state+j]);
 122                 }
 123                 if (len >= PAGE_SIZE)
 124                         break;
 125                 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 126         }
 127         if (len >= PAGE_SIZE)
 128                 return PAGE_SIZE;
 129         return len;
 130 }
 131 cpufreq_freq_attr_ro(trans_table);
 132 #endif
 133
 134 cpufreq_freq_attr_ro(total_trans);
 135 cpufreq_freq_attr_ro(time_in_state);
 136 cpufreq_freq_attr_wo(reset);
 137
 138 static struct attribute *default_attrs[] = {
 139         &total_trans.attr,
 140         &time_in_state.attr,
 141         &reset.attr,
 142 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 143         &trans_table.attr,
 144 #endif
 145         NULL
 146 };
 147 static struct attribute_group stats_attr_group = {
 148         .attrs = default_attrs,
 149         .name = "stats"
 150 };
 151
 152 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
 153 {
 154         int index;
 155         for (index = 0; index < stats->max_state; index++)
 156                 if (stats->freq_table[index] == freq)
 157                         return index;
 158         return -1;
 159 }
 160
 161 void cpufreq_stats_free_table(struct cpufreq_policy *policy)
 162 {
 163         struct cpufreq_stats *stats = policy->stats;
 164
 165         /* Already freed */
 166         if (!stats)
 167                 return;
 168
 169         pr_debug("%s: Free stats table\n", __func__);
 170
 171         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 172         kfree(stats->time_in_state);
 173         kfree(stats);
 174         policy->stats = NULL;
 175 }
 176
 177 void cpufreq_stats_create_table(struct cpufreq_policy *policy)
 178 {
 179         unsigned int i = 0, count = 0, ret = -ENOMEM;
 180         struct cpufreq_stats *stats;
 181         unsigned int alloc_size;
 182         struct cpufreq_frequency_table *pos, *table;
 183
 184         /* We need cpufreq table for creating stats table */
 185         table = policy->freq_table;
 186         if (unlikely(!table))
 187                 return;
 188
 189         /* stats already initialized */
 190         if (policy->stats)
 191                 return;
 192
 193         stats = kzalloc(sizeof(*stats), GFP_KERNEL);
 194         if (!stats)
 195                 return;
 196
 197         /* Find total allocation size */
 198         cpufreq_for_each_valid_entry(pos, table)
 199                 count++;
 200
 201         alloc_size = count * sizeof(int) + count * sizeof(u64);
 202
 203 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 204         alloc_size += count * count * sizeof(int);
 205 #endif
 206
 207         /* Allocate memory for time_in_state/freq_table/trans_table in one go */
 208         stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 209         if (!stats->time_in_state)
 210                 goto free_stat;
 211
 212         stats->freq_table = (unsigned int *)(stats->time_in_state + count);
 213
 214 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 215         stats->trans_table = stats->freq_table + count;
 216 #endif
 217
 218         stats->max_state = count;
 219
 220         /* Find valid-unique entries */
 221         cpufreq_for_each_valid_entry(pos, table)
 222                 if (freq_table_get_index(stats, pos->frequency) == -1)
 223                         stats->freq_table[i++] = pos->frequency;
 224
 225         stats->state_num = i;
 226         stats->last_time = get_jiffies_64();
 227         stats->last_index = freq_table_get_index(stats, policy->cur);
 228
 229         policy->stats = stats;
 230         ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
 231         if (!ret)
 232                 return;
 233
 234         /* We failed, release resources */
 235         policy->stats = NULL;
 236         kfree(stats->time_in_state);
 237 free_stat:
 238         kfree(stats);
 239 }
 240
 241 void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
 242                                      unsigned int new_freq)
 243 {
 244         struct cpufreq_stats *stats = policy->stats;
 245         int old_index, new_index;
 246
 247         if (!stats) {
 248                 pr_debug("%s: No stats found\n", __func__);
 249                 return;
 250         }
 251
 252         old_index = stats->last_index;
 253         new_index = freq_table_get_index(stats, new_freq);
 254
 255         /* We can't do stats->time_in_state[-1]= .. */
 256         if (old_index == -1 || new_index == -1 || old_index == new_index)
 257                 return;
 258
 259         cpufreq_stats_update(stats);
 260
 261         stats->last_index = new_index;
 262 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 263         stats->trans_table[old_index * stats->max_state + new_index]++;
 264 #endif
 265         stats->total_trans++;
 266 }