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/config.h> 13 #include <linux/kernel.h> 14 #include <linux/sysdev.h> 15 #include <linux/cpu.h> 16 #include <linux/sysfs.h> 17 #include <linux/cpufreq.h> 18 #include <linux/jiffies.h> 19 #include <linux/percpu.h> 20 #include <linux/kobject.h> 21 #include <linux/spinlock.h> 22 23 static spinlock_t cpufreq_stats_lock; 24 25 #define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \ 26 static struct freq_attr _attr_##_name = {\ 27 .attr = {.name = __stringify(_name), .owner = THIS_MODULE, \ 28 .mode = _mode, }, \ 29 .show = _show,\ 30 }; 31 32 static unsigned long 33 delta_time(unsigned long old, unsigned long new) 34 { 35 return (old > new) ? (old - new): (new + ~old + 1); 36 } 37 38 struct cpufreq_stats { 39 unsigned int cpu; 40 unsigned int total_trans; 41 unsigned long long last_time; 42 unsigned int max_state; 43 unsigned int state_num; 44 unsigned int last_index; 45 unsigned long long *time_in_state; 46 unsigned int *freq_table; 47 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 48 unsigned int *trans_table; 49 #endif 50 }; 51 52 static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS]; 53 54 struct cpufreq_stats_attribute { 55 struct attribute attr; 56 ssize_t(*show) (struct cpufreq_stats *, char *); 57 }; 58 59 static int 60 cpufreq_stats_update (unsigned int cpu) 61 { 62 struct cpufreq_stats *stat; 63 spin_lock(&cpufreq_stats_lock); 64 stat = cpufreq_stats_table[cpu]; 65 if (stat->time_in_state) 66 stat->time_in_state[stat->last_index] += 67 delta_time(stat->last_time, jiffies); 68 stat->last_time = jiffies; 69 spin_unlock(&cpufreq_stats_lock); 70 return 0; 71 } 72 73 static ssize_t 74 show_total_trans(struct cpufreq_policy *policy, char *buf) 75 { 76 struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu]; 77 if(!stat) 78 return 0; 79 return sprintf(buf, "%d\n", 80 cpufreq_stats_table[stat->cpu]->total_trans); 81 } 82 83 static ssize_t 84 show_time_in_state(struct cpufreq_policy *policy, char *buf) 85 { 86 ssize_t len = 0; 87 int i; 88 struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu]; 89 if(!stat) 90 return 0; 91 cpufreq_stats_update(stat->cpu); 92 for (i = 0; i < stat->state_num; i++) { 93 len += sprintf(buf + len, "%u %llu\n", 94 stat->freq_table[i], stat->time_in_state[i]); 95 } 96 return len; 97 } 98 99 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 100 static ssize_t 101 show_trans_table(struct cpufreq_policy *policy, char *buf) 102 { 103 ssize_t len = 0; 104 int i, j; 105 106 struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu]; 107 if(!stat) 108 return 0; 109 cpufreq_stats_update(stat->cpu); 110 for (i = 0; i < stat->state_num; i++) { 111 if (len >= PAGE_SIZE) 112 break; 113 len += snprintf(buf + len, PAGE_SIZE - len, "%9u:\t", 114 stat->freq_table[i]); 115 116 for (j = 0; j < stat->state_num; j++) { 117 if (len >= PAGE_SIZE) 118 break; 119 len += snprintf(buf + len, PAGE_SIZE - len, "%u\t", 120 stat->trans_table[i*stat->max_state+j]); 121 } 122 len += snprintf(buf + len, PAGE_SIZE - len, "\n"); 123 } 124 return len; 125 } 126 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table); 127 #endif 128 129 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans); 130 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state); 131 132 static struct attribute *default_attrs[] = { 133 &_attr_total_trans.attr, 134 &_attr_time_in_state.attr, 135 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 136 &_attr_trans_table.attr, 137 #endif 138 NULL 139 }; 140 static struct attribute_group stats_attr_group = { 141 .attrs = default_attrs, 142 .name = "stats" 143 }; 144 145 static int 146 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq) 147 { 148 int index; 149 for (index = 0; index < stat->max_state; index++) 150 if (stat->freq_table[index] == freq) 151 return index; 152 return -1; 153 } 154 155 static void 156 cpufreq_stats_free_table (unsigned int cpu) 157 { 158 struct cpufreq_stats *stat = cpufreq_stats_table[cpu]; 159 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); 160 if (policy && policy->cpu == cpu) 161 sysfs_remove_group(&policy->kobj, &stats_attr_group); 162 if (stat) { 163 kfree(stat->time_in_state); 164 kfree(stat); 165 } 166 cpufreq_stats_table[cpu] = NULL; 167 if (policy) 168 cpufreq_cpu_put(policy); 169 } 170 171 static int 172 cpufreq_stats_create_table (struct cpufreq_policy *policy, 173 struct cpufreq_frequency_table *table) 174 { 175 unsigned int i, j, count = 0, ret = 0; 176 struct cpufreq_stats *stat; 177 struct cpufreq_policy *data; 178 unsigned int alloc_size; 179 unsigned int cpu = policy->cpu; 180 if (cpufreq_stats_table[cpu]) 181 return -EBUSY; 182 if ((stat = kmalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL) 183 return -ENOMEM; 184 memset(stat, 0, sizeof (struct cpufreq_stats)); 185 186 data = cpufreq_cpu_get(cpu); 187 if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group))) 188 goto error_out; 189 190 stat->cpu = cpu; 191 cpufreq_stats_table[cpu] = stat; 192 193 for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) { 194 unsigned int freq = table[i].frequency; 195 if (freq == CPUFREQ_ENTRY_INVALID) 196 continue; 197 count++; 198 } 199 200 alloc_size = count * sizeof(int) + count * sizeof(long long); 201 202 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 203 alloc_size += count * count * sizeof(int); 204 #endif 205 stat->max_state = count; 206 stat->time_in_state = kmalloc(alloc_size, GFP_KERNEL); 207 if (!stat->time_in_state) { 208 ret = -ENOMEM; 209 goto error_out; 210 } 211 memset(stat->time_in_state, 0, alloc_size); 212 stat->freq_table = (unsigned int *)(stat->time_in_state + count); 213 214 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 215 stat->trans_table = stat->freq_table + count; 216 #endif 217 j = 0; 218 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { 219 unsigned int freq = table[i].frequency; 220 if (freq == CPUFREQ_ENTRY_INVALID) 221 continue; 222 if (freq_table_get_index(stat, freq) == -1) 223 stat->freq_table[j++] = freq; 224 } 225 stat->state_num = j; 226 spin_lock(&cpufreq_stats_lock); 227 stat->last_time = jiffies; 228 stat->last_index = freq_table_get_index(stat, policy->cur); 229 spin_unlock(&cpufreq_stats_lock); 230 cpufreq_cpu_put(data); 231 return 0; 232 error_out: 233 cpufreq_cpu_put(data); 234 kfree(stat); 235 cpufreq_stats_table[cpu] = NULL; 236 return ret; 237 } 238 239 static int 240 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val, 241 void *data) 242 { 243 int ret; 244 struct cpufreq_policy *policy = data; 245 struct cpufreq_frequency_table *table; 246 unsigned int cpu = policy->cpu; 247 if (val != CPUFREQ_NOTIFY) 248 return 0; 249 table = cpufreq_frequency_get_table(cpu); 250 if (!table) 251 return 0; 252 if ((ret = cpufreq_stats_create_table(policy, table))) 253 return ret; 254 return 0; 255 } 256 257 static int 258 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val, 259 void *data) 260 { 261 struct cpufreq_freqs *freq = data; 262 struct cpufreq_stats *stat; 263 int old_index, new_index; 264 265 if (val != CPUFREQ_POSTCHANGE) 266 return 0; 267 268 stat = cpufreq_stats_table[freq->cpu]; 269 if (!stat) 270 return 0; 271 old_index = freq_table_get_index(stat, freq->old); 272 new_index = freq_table_get_index(stat, freq->new); 273 274 cpufreq_stats_update(freq->cpu); 275 if (old_index == new_index) 276 return 0; 277 278 spin_lock(&cpufreq_stats_lock); 279 stat->last_index = new_index; 280 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS 281 stat->trans_table[old_index * stat->max_state + new_index]++; 282 #endif 283 stat->total_trans++; 284 spin_unlock(&cpufreq_stats_lock); 285 return 0; 286 } 287 288 static struct notifier_block notifier_policy_block = { 289 .notifier_call = cpufreq_stat_notifier_policy 290 }; 291 292 static struct notifier_block notifier_trans_block = { 293 .notifier_call = cpufreq_stat_notifier_trans 294 }; 295 296 static int 297 __init cpufreq_stats_init(void) 298 { 299 int ret; 300 unsigned int cpu; 301 spin_lock_init(&cpufreq_stats_lock); 302 if ((ret = cpufreq_register_notifier(¬ifier_policy_block, 303 CPUFREQ_POLICY_NOTIFIER))) 304 return ret; 305 306 if ((ret = cpufreq_register_notifier(¬ifier_trans_block, 307 CPUFREQ_TRANSITION_NOTIFIER))) { 308 cpufreq_unregister_notifier(¬ifier_policy_block, 309 CPUFREQ_POLICY_NOTIFIER); 310 return ret; 311 } 312 313 for_each_cpu(cpu) 314 cpufreq_update_policy(cpu); 315 return 0; 316 } 317 static void 318 __exit cpufreq_stats_exit(void) 319 { 320 unsigned int cpu; 321 cpufreq_unregister_notifier(¬ifier_policy_block, 322 CPUFREQ_POLICY_NOTIFIER); 323 cpufreq_unregister_notifier(¬ifier_trans_block, 324 CPUFREQ_TRANSITION_NOTIFIER); 325 for_each_cpu(cpu) 326 cpufreq_stats_free_table(cpu); 327 } 328 329 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>"); 330 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem"); 331 MODULE_LICENSE ("GPL"); 332 333 module_init(cpufreq_stats_init); 334 module_exit(cpufreq_stats_exit); 335