linux/drivers/cpufreq/cpufreq_stats.c
<<
>>
Prefs
   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/kernel.h>
  13#include <linux/sysdev.h>
  14#include <linux/cpu.h>
  15#include <linux/sysfs.h>
  16#include <linux/cpufreq.h>
  17#include <linux/jiffies.h>
  18#include <linux/percpu.h>
  19#include <linux/kobject.h>
  20#include <linux/spinlock.h>
  21#include <linux/notifier.h>
  22#include <asm/cputime.h>
  23
  24static spinlock_t cpufreq_stats_lock;
  25
  26#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
  27static struct freq_attr _attr_##_name = {\
  28        .attr = {.name = __stringify(_name), .mode = _mode, }, \
  29        .show = _show,\
  30};
  31
  32struct cpufreq_stats {
  33        unsigned int cpu;
  34        unsigned int total_trans;
  35        unsigned long long  last_time;
  36        unsigned int max_state;
  37        unsigned int state_num;
  38        unsigned int last_index;
  39        cputime64_t *time_in_state;
  40        unsigned int *freq_table;
  41#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  42        unsigned int *trans_table;
  43#endif
  44};
  45
  46static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
  47
  48struct cpufreq_stats_attribute {
  49        struct attribute attr;
  50        ssize_t(*show) (struct cpufreq_stats *, char *);
  51};
  52
  53static int
  54cpufreq_stats_update (unsigned int cpu)
  55{
  56        struct cpufreq_stats *stat;
  57        unsigned long long cur_time;
  58
  59        cur_time = get_jiffies_64();
  60        spin_lock(&cpufreq_stats_lock);
  61        stat = per_cpu(cpufreq_stats_table, cpu);
  62        if (stat->time_in_state)
  63                stat->time_in_state[stat->last_index] =
  64                        cputime64_add(stat->time_in_state[stat->last_index],
  65                                      cputime_sub(cur_time, stat->last_time));
  66        stat->last_time = cur_time;
  67        spin_unlock(&cpufreq_stats_lock);
  68        return 0;
  69}
  70
  71static ssize_t
  72show_total_trans(struct cpufreq_policy *policy, char *buf)
  73{
  74        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  75        if (!stat)
  76                return 0;
  77        return sprintf(buf, "%d\n",
  78                        per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
  79}
  80
  81static ssize_t
  82show_time_in_state(struct cpufreq_policy *policy, char *buf)
  83{
  84        ssize_t len = 0;
  85        int i;
  86        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
  87        if (!stat)
  88                return 0;
  89        cpufreq_stats_update(stat->cpu);
  90        for (i = 0; i < stat->state_num; i++) {
  91                len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
  92                        (unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
  93        }
  94        return len;
  95}
  96
  97#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
  98static ssize_t
  99show_trans_table(struct cpufreq_policy *policy, char *buf)
 100{
 101        ssize_t len = 0;
 102        int i, j;
 103
 104        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 105        if (!stat)
 106                return 0;
 107        cpufreq_stats_update(stat->cpu);
 108        len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 109        len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 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 ",
 114                                stat->freq_table[i]);
 115        }
 116        if (len >= PAGE_SIZE)
 117                return PAGE_SIZE;
 118
 119        len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 120
 121        for (i = 0; i < stat->state_num; i++) {
 122                if (len >= PAGE_SIZE)
 123                        break;
 124
 125                len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 126                                stat->freq_table[i]);
 127
 128                for (j = 0; j < stat->state_num; j++)   {
 129                        if (len >= PAGE_SIZE)
 130                                break;
 131                        len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
 132                                        stat->trans_table[i*stat->max_state+j]);
 133                }
 134                if (len >= PAGE_SIZE)
 135                        break;
 136                len += snprintf(buf + len, PAGE_SIZE - len, "\n");
 137        }
 138        if (len >= PAGE_SIZE)
 139                return PAGE_SIZE;
 140        return len;
 141}
 142CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
 143#endif
 144
 145CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
 146CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
 147
 148static struct attribute *default_attrs[] = {
 149        &_attr_total_trans.attr,
 150        &_attr_time_in_state.attr,
 151#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 152        &_attr_trans_table.attr,
 153#endif
 154        NULL
 155};
 156static struct attribute_group stats_attr_group = {
 157        .attrs = default_attrs,
 158        .name = "stats"
 159};
 160
 161static int
 162freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 163{
 164        int index;
 165        for (index = 0; index < stat->max_state; index++)
 166                if (stat->freq_table[index] == freq)
 167                        return index;
 168        return -1;
 169}
 170
 171static void cpufreq_stats_free_table(unsigned int cpu)
 172{
 173        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
 174        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 175        if (policy && policy->cpu == cpu)
 176                sysfs_remove_group(&policy->kobj, &stats_attr_group);
 177        if (stat) {
 178                kfree(stat->time_in_state);
 179                kfree(stat);
 180        }
 181        per_cpu(cpufreq_stats_table, cpu) = NULL;
 182        if (policy)
 183                cpufreq_cpu_put(policy);
 184}
 185
 186static int
 187cpufreq_stats_create_table (struct cpufreq_policy *policy,
 188                struct cpufreq_frequency_table *table)
 189{
 190        unsigned int i, j, count = 0, ret = 0;
 191        struct cpufreq_stats *stat;
 192        struct cpufreq_policy *data;
 193        unsigned int alloc_size;
 194        unsigned int cpu = policy->cpu;
 195        if (per_cpu(cpufreq_stats_table, cpu))
 196                return -EBUSY;
 197        if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
 198                return -ENOMEM;
 199
 200        data = cpufreq_cpu_get(cpu);
 201        if (data == NULL) {
 202                ret = -EINVAL;
 203                goto error_get_fail;
 204        }
 205
 206        if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
 207                goto error_out;
 208
 209        stat->cpu = cpu;
 210        per_cpu(cpufreq_stats_table, cpu) = stat;
 211
 212        for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 213                unsigned int freq = table[i].frequency;
 214                if (freq == CPUFREQ_ENTRY_INVALID)
 215                        continue;
 216                count++;
 217        }
 218
 219        alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
 220
 221#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 222        alloc_size += count * count * sizeof(int);
 223#endif
 224        stat->max_state = count;
 225        stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
 226        if (!stat->time_in_state) {
 227                ret = -ENOMEM;
 228                goto error_out;
 229        }
 230        stat->freq_table = (unsigned int *)(stat->time_in_state + count);
 231
 232#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 233        stat->trans_table = stat->freq_table + count;
 234#endif
 235        j = 0;
 236        for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
 237                unsigned int freq = table[i].frequency;
 238                if (freq == CPUFREQ_ENTRY_INVALID)
 239                        continue;
 240                if (freq_table_get_index(stat, freq) == -1)
 241                        stat->freq_table[j++] = freq;
 242        }
 243        stat->state_num = j;
 244        spin_lock(&cpufreq_stats_lock);
 245        stat->last_time = get_jiffies_64();
 246        stat->last_index = freq_table_get_index(stat, policy->cur);
 247        spin_unlock(&cpufreq_stats_lock);
 248        cpufreq_cpu_put(data);
 249        return 0;
 250error_out:
 251        cpufreq_cpu_put(data);
 252error_get_fail:
 253        kfree(stat);
 254        per_cpu(cpufreq_stats_table, cpu) = NULL;
 255        return ret;
 256}
 257
 258static int
 259cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
 260                void *data)
 261{
 262        int ret;
 263        struct cpufreq_policy *policy = data;
 264        struct cpufreq_frequency_table *table;
 265        unsigned int cpu = policy->cpu;
 266        if (val != CPUFREQ_NOTIFY)
 267                return 0;
 268        table = cpufreq_frequency_get_table(cpu);
 269        if (!table)
 270                return 0;
 271        if ((ret = cpufreq_stats_create_table(policy, table)))
 272                return ret;
 273        return 0;
 274}
 275
 276static int
 277cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
 278                void *data)
 279{
 280        struct cpufreq_freqs *freq = data;
 281        struct cpufreq_stats *stat;
 282        int old_index, new_index;
 283
 284        if (val != CPUFREQ_POSTCHANGE)
 285                return 0;
 286
 287        stat = per_cpu(cpufreq_stats_table, freq->cpu);
 288        if (!stat)
 289                return 0;
 290
 291        old_index = stat->last_index;
 292        new_index = freq_table_get_index(stat, freq->new);
 293
 294        cpufreq_stats_update(freq->cpu);
 295        if (old_index == new_index)
 296                return 0;
 297
 298        if (old_index == -1 || new_index == -1)
 299                return 0;
 300
 301        spin_lock(&cpufreq_stats_lock);
 302        stat->last_index = new_index;
 303#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 304        stat->trans_table[old_index * stat->max_state + new_index]++;
 305#endif
 306        stat->total_trans++;
 307        spin_unlock(&cpufreq_stats_lock);
 308        return 0;
 309}
 310
 311static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
 312                                               unsigned long action,
 313                                               void *hcpu)
 314{
 315        unsigned int cpu = (unsigned long)hcpu;
 316
 317        switch (action) {
 318        case CPU_ONLINE:
 319        case CPU_ONLINE_FROZEN:
 320                cpufreq_update_policy(cpu);
 321                break;
 322        case CPU_DEAD:
 323        case CPU_DEAD_FROZEN:
 324                cpufreq_stats_free_table(cpu);
 325                break;
 326        }
 327        return NOTIFY_OK;
 328}
 329
 330static struct notifier_block cpufreq_stat_cpu_notifier __refdata =
 331{
 332        .notifier_call = cpufreq_stat_cpu_callback,
 333};
 334
 335static struct notifier_block notifier_policy_block = {
 336        .notifier_call = cpufreq_stat_notifier_policy
 337};
 338
 339static struct notifier_block notifier_trans_block = {
 340        .notifier_call = cpufreq_stat_notifier_trans
 341};
 342
 343static int
 344__init cpufreq_stats_init(void)
 345{
 346        int ret;
 347        unsigned int cpu;
 348
 349        spin_lock_init(&cpufreq_stats_lock);
 350        if ((ret = cpufreq_register_notifier(&notifier_policy_block,
 351                                CPUFREQ_POLICY_NOTIFIER)))
 352                return ret;
 353
 354        if ((ret = cpufreq_register_notifier(&notifier_trans_block,
 355                                CPUFREQ_TRANSITION_NOTIFIER))) {
 356                cpufreq_unregister_notifier(&notifier_policy_block,
 357                                CPUFREQ_POLICY_NOTIFIER);
 358                return ret;
 359        }
 360
 361        register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 362        for_each_online_cpu(cpu) {
 363                cpufreq_update_policy(cpu);
 364        }
 365        return 0;
 366}
 367static void
 368__exit cpufreq_stats_exit(void)
 369{
 370        unsigned int cpu;
 371
 372        cpufreq_unregister_notifier(&notifier_policy_block,
 373                        CPUFREQ_POLICY_NOTIFIER);
 374        cpufreq_unregister_notifier(&notifier_trans_block,
 375                        CPUFREQ_TRANSITION_NOTIFIER);
 376        unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
 377        for_each_online_cpu(cpu) {
 378                cpufreq_stats_free_table(cpu);
 379        }
 380}
 381
 382MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
 383MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats "
 384                                "through sysfs filesystem");
 385MODULE_LICENSE ("GPL");
 386
 387module_init(cpufreq_stats_init);
 388module_exit(cpufreq_stats_exit);
 389
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.