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