[deliverable/linux.git] / drivers / cpufreq / cpufreq_stats.c

/*
 *  drivers/cpufreq/cpufreq_stats.c
 *
 *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *  	      (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/sysfs.h>
#include <linux/cpufreq.h>
#include <linux/jiffies.h>
#include <linux/percpu.h>
#include <linux/kobject.h>
#include <linux/spinlock.h>
#include <asm/cputime.h>

static spinlock_t cpufreq_stats_lock;

#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
static struct freq_attr _attr_##_name = {\
	.attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
		.mode = _mode, }, \
	.show = _show,\
};

struct cpufreq_stats {
	unsigned int cpu;
	unsigned int total_trans;
	unsigned long long  last_time;
	unsigned int max_state;
	unsigned int state_num;
	unsigned int last_index;
	cputime64_t *time_in_state;
	unsigned int *freq_table;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	unsigned int *trans_table;
#endif
};

static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];

struct cpufreq_stats_attribute {
	struct attribute attr;
	ssize_t(*show) (struct cpufreq_stats *, char *);
};

static int
cpufreq_stats_update (unsigned int cpu)
{
	struct cpufreq_stats *stat;
	unsigned long long cur_time;

	cur_time = get_jiffies_64();
	spin_lock(&cpufreq_stats_lock);
	stat = cpufreq_stats_table[cpu];
	if (stat->time_in_state)
		stat->time_in_state[stat->last_index] =
			cputime64_add(stat->time_in_state[stat->last_index],
				      cputime_sub(cur_time, stat->last_time));
	stat->last_time = cur_time;
	spin_unlock(&cpufreq_stats_lock);
	return 0;
}

static ssize_t
show_total_trans(struct cpufreq_policy *policy, char *buf)
{
	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	if(!stat)
		return 0;
	return sprintf(buf, "%d\n",
			cpufreq_stats_table[stat->cpu]->total_trans);
}

static ssize_t
show_time_in_state(struct cpufreq_policy *policy, char *buf)
{
	ssize_t len = 0;
	int i;
	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	if(!stat)
		return 0;
	cpufreq_stats_update(stat->cpu);
	for (i = 0; i < stat->state_num; i++) {
		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i], 
			(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
	}
	return len;
}

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
static ssize_t
show_trans_table(struct cpufreq_policy *policy, char *buf)
{
	ssize_t len = 0;
	int i, j;

	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	if(!stat)
		return 0;
	cpufreq_stats_update(stat->cpu);
	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
	for (i = 0; i < stat->state_num; i++) {
		if (len >= PAGE_SIZE)
			break;
		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
				stat->freq_table[i]);
	}
	if (len >= PAGE_SIZE)
		return len;

	len += snprintf(buf + len, PAGE_SIZE - len, "\n");

	for (i = 0; i < stat->state_num; i++) {
		if (len >= PAGE_SIZE)
			break;

		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
				stat->freq_table[i]);

		for (j = 0; j < stat->state_num; j++)   {
			if (len >= PAGE_SIZE)
				break;
			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
					stat->trans_table[i*stat->max_state+j]);
		}
		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
	}
	return len;
}
CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
#endif

CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);

static struct attribute *default_attrs[] = {
	&_attr_total_trans.attr,
	&_attr_time_in_state.attr,
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	&_attr_trans_table.attr,
#endif
	NULL
};
static struct attribute_group stats_attr_group = {
	.attrs = default_attrs,
	.name = "stats"
};

static int
freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
{
	int index;
	for (index = 0; index < stat->max_state; index++)
		if (stat->freq_table[index] == freq)
			return index;
	return -1;
}

static void
cpufreq_stats_free_table (unsigned int cpu)
{
	struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
	if (policy && policy->cpu == cpu)	
		sysfs_remove_group(&policy->kobj, &stats_attr_group);
	if (stat) {
		kfree(stat->time_in_state);
		kfree(stat);
	}
	cpufreq_stats_table[cpu] = NULL;
	if (policy)
		cpufreq_cpu_put(policy);
}

static int
cpufreq_stats_create_table (struct cpufreq_policy *policy,
		struct cpufreq_frequency_table *table)
{
	unsigned int i, j, count = 0, ret = 0;
	struct cpufreq_stats *stat;
	struct cpufreq_policy *data;
	unsigned int alloc_size;
	unsigned int cpu = policy->cpu;
	if (cpufreq_stats_table[cpu])
		return -EBUSY;
	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
		return -ENOMEM;

	data = cpufreq_cpu_get(cpu);
	if (data == NULL) {
		ret = -EINVAL;
		goto error_get_fail;
	}

	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
		goto error_out;

	stat->cpu = cpu;
	cpufreq_stats_table[cpu] = stat;

	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
		unsigned int freq = table[i].frequency;
		if (freq == CPUFREQ_ENTRY_INVALID)
			continue;
		count++;
	}

	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	alloc_size += count * count * sizeof(int);
#endif
	stat->max_state = count;
	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
	if (!stat->time_in_state) {
		ret = -ENOMEM;
		goto error_out;
	}
	stat->freq_table = (unsigned int *)(stat->time_in_state + count);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	stat->trans_table = stat->freq_table + count;
#endif
	j = 0;
	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
		unsigned int freq = table[i].frequency;
		if (freq == CPUFREQ_ENTRY_INVALID)
			continue;
		if (freq_table_get_index(stat, freq) == -1)
			stat->freq_table[j++] = freq;
	}
	stat->state_num = j;
	spin_lock(&cpufreq_stats_lock);
	stat->last_time = get_jiffies_64();
	stat->last_index = freq_table_get_index(stat, policy->cur);
	spin_unlock(&cpufreq_stats_lock);
	cpufreq_cpu_put(data);
	return 0;
error_out:
	cpufreq_cpu_put(data);
error_get_fail:
	kfree(stat);
	cpufreq_stats_table[cpu] = NULL;
	return ret;
}

static int
cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
		void *data)
{
	int ret;
	struct cpufreq_policy *policy = data;
	struct cpufreq_frequency_table *table;
	unsigned int cpu = policy->cpu;
	if (val != CPUFREQ_NOTIFY)
		return 0;
	table = cpufreq_frequency_get_table(cpu);
	if (!table)
		return 0;
	if ((ret = cpufreq_stats_create_table(policy, table)))
		return ret;
	return 0;
}

static int
cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
		void *data)
{
	struct cpufreq_freqs *freq = data;
	struct cpufreq_stats *stat;
	int old_index, new_index;

	if (val != CPUFREQ_POSTCHANGE)
		return 0;

	stat = cpufreq_stats_table[freq->cpu];
	if (!stat)
		return 0;
	old_index = freq_table_get_index(stat, freq->old);
	new_index = freq_table_get_index(stat, freq->new);

	cpufreq_stats_update(freq->cpu);
	if (old_index == new_index)
		return 0;

	spin_lock(&cpufreq_stats_lock);
	stat->last_index = new_index;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	stat->trans_table[old_index * stat->max_state + new_index]++;
#endif
	stat->total_trans++;
	spin_unlock(&cpufreq_stats_lock);
	return 0;
}

static struct notifier_block notifier_policy_block = {
	.notifier_call = cpufreq_stat_notifier_policy
};

static struct notifier_block notifier_trans_block = {
	.notifier_call = cpufreq_stat_notifier_trans
};

static int
__init cpufreq_stats_init(void)
{
	int ret;
	unsigned int cpu;
	spin_lock_init(&cpufreq_stats_lock);
	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
				CPUFREQ_POLICY_NOTIFIER)))
		return ret;

	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
				CPUFREQ_TRANSITION_NOTIFIER))) {
		cpufreq_unregister_notifier(&notifier_policy_block,
				CPUFREQ_POLICY_NOTIFIER);
		return ret;
	}

	for_each_cpu(cpu)
		cpufreq_update_policy(cpu);
	return 0;
}
static void
__exit cpufreq_stats_exit(void)
{
	unsigned int cpu;
	cpufreq_unregister_notifier(&notifier_policy_block,
			CPUFREQ_POLICY_NOTIFIER);
	cpufreq_unregister_notifier(&notifier_trans_block,
			CPUFREQ_TRANSITION_NOTIFIER);
	for_each_cpu(cpu)
		cpufreq_stats_free_table(cpu);
}

MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
MODULE_LICENSE ("GPL");

module_init(cpufreq_stats_init);
module_exit(cpufreq_stats_exit);
Commit	Line	Data
1da177e4 LT	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>
58f1df25	22	#include <asm/cputime.h>
1da177e4 LT	23
	24	static spinlock_t cpufreq_stats_lock;
	25
	26	#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
	27	static struct freq_attr _attr_##_name = {\
	28	.attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
	29	.mode = _mode, }, \
	30	.show = _show,\
	31	};
	32
1da177e4 LT	33	struct cpufreq_stats {
	34	unsigned int cpu;
	35	unsigned int total_trans;
58f1df25	36	unsigned long long last_time;
1da177e4 LT	37	unsigned int max_state;
	38	unsigned int state_num;
	39	unsigned int last_index;
58f1df25	40	cputime64_t *time_in_state;
1da177e4 LT	41	unsigned int *freq_table;
	42	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	43	unsigned int *trans_table;
	44	#endif
	45	};
	46
	47	static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
	48
	49	struct cpufreq_stats_attribute {
	50	struct attribute attr;
	51	ssize_t(show) (struct cpufreq_stats , char *);
	52	};
	53
	54	static int
	55	cpufreq_stats_update (unsigned int cpu)
	56	{
	57	struct cpufreq_stats *stat;
58f1df25 VP	58	unsigned long long cur_time;
	59
	60	cur_time = get_jiffies_64();
1da177e4 LT	61	spin_lock(&cpufreq_stats_lock);
	62	stat = cpufreq_stats_table[cpu];
	63	if (stat->time_in_state)
58f1df25 VP	64	stat->time_in_state[stat->last_index] =
	65	cputime64_add(stat->time_in_state[stat->last_index],
	66	cputime_sub(cur_time, stat->last_time));
	67	stat->last_time = cur_time;
1da177e4 LT	68	spin_unlock(&cpufreq_stats_lock);
	69	return 0;
	70	}
	71
	72	static ssize_t
	73	show_total_trans(struct cpufreq_policy policy, char buf)
	74	{
	75	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	76	if(!stat)
	77	return 0;
	78	return sprintf(buf, "%d\n",
	79	cpufreq_stats_table[stat->cpu]->total_trans);
	80	}
	81
	82	static ssize_t
	83	show_time_in_state(struct cpufreq_policy policy, char buf)
	84	{
	85	ssize_t len = 0;
	86	int i;
	87	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	88	if(!stat)
	89	return 0;
	90	cpufreq_stats_update(stat->cpu);
	91	for (i = 0; i < stat->state_num; i++) {
58f1df25 VP	92	len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
58f1df25 VP	93	(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
1da177e4 LT	94	}
	95	return len;
	96	}
	97
	98	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	99	static ssize_t
	100	show_trans_table(struct cpufreq_policy policy, char buf)
	101	{
	102	ssize_t len = 0;
	103	int i, j;
	104
	105	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
	106	if(!stat)
	107	return 0;
	108	cpufreq_stats_update(stat->cpu);
58f1df25 VP	109	len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
	110	len += snprintf(buf + len, PAGE_SIZE - len, " : ");
	111	for (i = 0; i < stat->state_num; i++) {
	112	if (len >= PAGE_SIZE)
	113	break;
	114	len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
	115	stat->freq_table[i]);
	116	}
	117	if (len >= PAGE_SIZE)
	118	return len;
	119
	120	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
	121
1da177e4 LT	122	for (i = 0; i < stat->state_num; i++) {
	123	if (len >= PAGE_SIZE)
	124	break;
58f1df25 VP	125
58f1df25 VP	126	len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
1da177e4 LT	127	stat->freq_table[i]);
	128
	129	for (j = 0; j < stat->state_num; j++) {
	130	if (len >= PAGE_SIZE)
	131	break;
58f1df25	132	len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
1da177e4 LT	133	stat->trans_table[i*stat->max_state+j]);
	134	}
	135	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
	136	}
	137	return len;
	138	}
	139	CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
	140	#endif
	141
	142	CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
	143	CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
	144
	145	static struct attribute *default_attrs[] = {
	146	&_attr_total_trans.attr,
	147	&_attr_time_in_state.attr,
	148	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	149	&_attr_trans_table.attr,
	150	#endif
	151	NULL
	152	};
	153	static struct attribute_group stats_attr_group = {
	154	.attrs = default_attrs,
	155	.name = "stats"
	156	};
	157
	158	static int
	159	freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
	160	{
	161	int index;
	162	for (index = 0; index < stat->max_state; index++)
	163	if (stat->freq_table[index] == freq)
	164	return index;
	165	return -1;
	166	}
	167
	168	static void
	169	cpufreq_stats_free_table (unsigned int cpu)
	170	{
	171	struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
	172	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
	173	if (policy && policy->cpu == cpu)
	174	sysfs_remove_group(&policy->kobj, &stats_attr_group);
	175	if (stat) {
	176	kfree(stat->time_in_state);
	177	kfree(stat);
	178	}
	179	cpufreq_stats_table[cpu] = NULL;
	180	if (policy)
	181	cpufreq_cpu_put(policy);
	182	}
	183
	184	static int
	185	cpufreq_stats_create_table (struct cpufreq_policy *policy,
	186	struct cpufreq_frequency_table *table)
	187	{
	188	unsigned int i, j, count = 0, ret = 0;
	189	struct cpufreq_stats *stat;
	190	struct cpufreq_policy *data;
	191	unsigned int alloc_size;
	192	unsigned int cpu = policy->cpu;
	193	if (cpufreq_stats_table[cpu])
	194	return -EBUSY;
e98df50c	195	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
1da177e4	196	return -ENOMEM;
1da177e4 LT	197
1da177e4 LT	198	data = cpufreq_cpu_get(cpu);
bc7b26fd DJ	199	if (data == NULL) {
	200	ret = -EINVAL;
	201	goto error_get_fail;
	202	}
	203
1da177e4 LT	204	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
	205	goto error_out;
	206
	207	stat->cpu = cpu;
	208	cpufreq_stats_table[cpu] = stat;
	209
	210	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
	211	unsigned int freq = table[i].frequency;
	212	if (freq == CPUFREQ_ENTRY_INVALID)
	213	continue;
	214	count++;
	215	}
	216
58f1df25	217	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
1da177e4 LT	218
	219	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	220	alloc_size += count * count * sizeof(int);
	221	#endif
	222	stat->max_state = count;
e98df50c	223	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
1da177e4 LT	224	if (!stat->time_in_state) {
	225	ret = -ENOMEM;
	226	goto error_out;
	227	}
1da177e4 LT	228	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
	229
	230	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	231	stat->trans_table = stat->freq_table + count;
	232	#endif
	233	j = 0;
	234	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
	235	unsigned int freq = table[i].frequency;
	236	if (freq == CPUFREQ_ENTRY_INVALID)
	237	continue;
	238	if (freq_table_get_index(stat, freq) == -1)
	239	stat->freq_table[j++] = freq;
	240	}
	241	stat->state_num = j;
	242	spin_lock(&cpufreq_stats_lock);
58f1df25	243	stat->last_time = get_jiffies_64();
1da177e4 LT	244	stat->last_index = freq_table_get_index(stat, policy->cur);
	245	spin_unlock(&cpufreq_stats_lock);
	246	cpufreq_cpu_put(data);
	247	return 0;
	248	error_out:
	249	cpufreq_cpu_put(data);
b7fb358c	250	error_get_fail:
1da177e4 LT	251	kfree(stat);
	252	cpufreq_stats_table[cpu] = NULL;
	253	return ret;
	254	}
	255
	256	static int
	257	cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
	258	void *data)
	259	{
	260	int ret;
	261	struct cpufreq_policy *policy = data;
	262	struct cpufreq_frequency_table *table;
	263	unsigned int cpu = policy->cpu;
	264	if (val != CPUFREQ_NOTIFY)
	265	return 0;
	266	table = cpufreq_frequency_get_table(cpu);
	267	if (!table)
	268	return 0;
	269	if ((ret = cpufreq_stats_create_table(policy, table)))
	270	return ret;
	271	return 0;
	272	}
	273
	274	static int
	275	cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
	276	void *data)
	277	{
	278	struct cpufreq_freqs *freq = data;
	279	struct cpufreq_stats *stat;
	280	int old_index, new_index;
	281
	282	if (val != CPUFREQ_POSTCHANGE)
	283	return 0;
	284
	285	stat = cpufreq_stats_table[freq->cpu];
	286	if (!stat)
	287	return 0;
	288	old_index = freq_table_get_index(stat, freq->old);
	289	new_index = freq_table_get_index(stat, freq->new);
	290
	291	cpufreq_stats_update(freq->cpu);
	292	if (old_index == new_index)
	293	return 0;
	294
	295	spin_lock(&cpufreq_stats_lock);
	296	stat->last_index = new_index;
	297	#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	298	stat->trans_table[old_index * stat->max_state + new_index]++;
	299	#endif
	300	stat->total_trans++;
	301	spin_unlock(&cpufreq_stats_lock);
	302	return 0;
	303	}
	304
	305	static struct notifier_block notifier_policy_block = {
	306	.notifier_call = cpufreq_stat_notifier_policy
	307	};
	308
	309	static struct notifier_block notifier_trans_block = {
	310	.notifier_call = cpufreq_stat_notifier_trans
	311	};
	312
	313	static int
	314	__init cpufreq_stats_init(void)
315	{
316	int ret;
317	unsigned int cpu;
318	spin_lock_init(&cpufreq_stats_lock);
319	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
320	CPUFREQ_POLICY_NOTIFIER)))
321	return ret;
322
323	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
324	CPUFREQ_TRANSITION_NOTIFIER))) {
325	cpufreq_unregister_notifier(&notifier_policy_block,
326	CPUFREQ_POLICY_NOTIFIER);
327	return ret;
328	}
329
330	for_each_cpu(cpu)
331	cpufreq_update_policy(cpu);
332	return 0;
333	}
334	static void
335	__exit cpufreq_stats_exit(void)
336	{
337	unsigned int cpu;
338	cpufreq_unregister_notifier(&notifier_policy_block,
339	CPUFREQ_POLICY_NOTIFIER);
340	cpufreq_unregister_notifier(&notifier_trans_block,
341	CPUFREQ_TRANSITION_NOTIFIER);
342	for_each_cpu(cpu)
343	cpufreq_stats_free_table(cpu);
344	}
345
346	MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
347	MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
348	MODULE_LICENSE ("GPL");
349
350	module_init(cpufreq_stats_init);
351	module_exit(cpufreq_stats_exit);