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