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