cpufreq_stats.c revision 5c720d37bf5c2864cd7e834afff88321d6e4d97d 
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/slab.h>
14#include <linux/sysdev.h>
15#include <linux/cpu.h>
16#include <linux/sysfs.h>
17#include <linux/cpufreq.h>
18#include <linux/module.h>
19#include <linux/jiffies.h>
20#include <linux/percpu.h>
21#include <linux/kobject.h>
22#include <linux/spinlock.h>
23#include <linux/notifier.h>
24#include <asm/cputime.h>
25
26static spinlock_t cpufreq_stats_lock;
27
28#define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
29static struct freq_attr _attr_##_name = {\
30	.attr = {.name = __stringify(_name), .mode = _mode, }, \
31	.show = _show,\
32};
33
34struct cpufreq_stats {
35	unsigned int cpu;
36	unsigned int total_trans;
37	unsigned long long  last_time;
38	unsigned int max_state;
39	unsigned int state_num;
40	unsigned int last_index;
41	cputime64_t *time_in_state;
42	unsigned int *freq_table;
43#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
44	unsigned int *trans_table;
45#endif
46};
47
48static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
49
50struct cpufreq_stats_attribute {
51	struct attribute attr;
52	ssize_t(*show) (struct cpufreq_stats *, char *);
53};
54
55static int cpufreq_stats_update(unsigned int cpu)
56{
57	struct cpufreq_stats *stat;
58	unsigned long long cur_time;
59
60	cur_time = get_jiffies_64();
61	spin_lock(&cpufreq_stats_lock);
62	stat = per_cpu(cpufreq_stats_table, cpu);
63	if (stat->time_in_state)
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;
68	spin_unlock(&cpufreq_stats_lock);
69	return 0;
70}
71
72static ssize_t show_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 show_time_in_state(struct cpufreq_policy *policy, char *buf)
82{
83	ssize_t len = 0;
84	int i;
85	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
86	if (!stat)
87		return 0;
88	cpufreq_stats_update(stat->cpu);
89	for (i = 0; i < stat->state_num; i++) {
90		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
91			(unsigned long long)
92			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 show_trans_table(struct cpufreq_policy *policy, char *buf)
99{
100	ssize_t len = 0;
101	int i, j;
102
103	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
104	if (!stat)
105		return 0;
106	cpufreq_stats_update(stat->cpu);
107	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
108	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
109	for (i = 0; i < stat->state_num; i++) {
110		if (len >= PAGE_SIZE)
111			break;
112		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
113				stat->freq_table[i]);
114	}
115	if (len >= PAGE_SIZE)
116		return PAGE_SIZE;
117
118	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
119
120	for (i = 0; i < stat->state_num; i++) {
121		if (len >= PAGE_SIZE)
122			break;
123
124		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
125				stat->freq_table[i]);
126
127		for (j = 0; j < stat->state_num; j++)   {
128			if (len >= PAGE_SIZE)
129				break;
130			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
131					stat->trans_table[i*stat->max_state+j]);
132		}
133		if (len >= PAGE_SIZE)
134			break;
135		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
136	}
137	if (len >= PAGE_SIZE)
138		return PAGE_SIZE;
139	return len;
140}
141CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
142#endif
143
144CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
145CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
146
147static struct attribute *default_attrs[] = {
148	&_attr_total_trans.attr,
149	&_attr_time_in_state.attr,
150#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
151	&_attr_trans_table.attr,
152#endif
153	NULL
154};
155static struct attribute_group stats_attr_group = {
156	.attrs = default_attrs,
157	.name = "stats"
158};
159
160static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
161{
162	int index;
163	for (index = 0; index < stat->max_state; index++)
164		if (stat->freq_table[index] == freq)
165			return index;
166	return -1;
167}
168
169/* should be called late in the CPU removal sequence so that the stats
170 * memory is still available in case someone tries to use it.
171 */
172static void cpufreq_stats_free_table(unsigned int cpu)
173{
174	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
175	if (stat) {
176		kfree(stat->time_in_state);
177		kfree(stat);
178	}
179	per_cpu(cpufreq_stats_table, cpu) = NULL;
180}
181
182/* must be called early in the CPU removal sequence (before
183 * cpufreq_remove_dev) so that policy is still valid.
184 */
185static void cpufreq_stats_free_sysfs(unsigned int cpu)
186{
187	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
188	if (policy && policy->cpu == cpu)
189		sysfs_remove_group(&policy->kobj, &stats_attr_group);
190	if (policy)
191		cpufreq_cpu_put(policy);
192}
193
194static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
195		struct cpufreq_frequency_table *table)
196{
197	unsigned int i, j, count = 0, ret = 0;
198	struct cpufreq_stats *stat;
199	struct cpufreq_policy *data;
200	unsigned int alloc_size;
201	unsigned int cpu = policy->cpu;
202	if (per_cpu(cpufreq_stats_table, cpu))
203		return -EBUSY;
204	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
205	if ((stat) == NULL)
206		return -ENOMEM;
207
208	data = cpufreq_cpu_get(cpu);
209	if (data == NULL) {
210		ret = -EINVAL;
211		goto error_get_fail;
212	}
213
214	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
215	if (ret)
216		goto error_out;
217
218	stat->cpu = cpu;
219	per_cpu(cpufreq_stats_table, cpu) = stat;
220
221	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
222		unsigned int freq = table[i].frequency;
223		if (freq == CPUFREQ_ENTRY_INVALID)
224			continue;
225		count++;
226	}
227
228	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
229
230#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
231	alloc_size += count * count * sizeof(int);
232#endif
233	stat->max_state = count;
234	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
235	if (!stat->time_in_state) {
236		ret = -ENOMEM;
237		goto error_out;
238	}
239	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
240
241#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
242	stat->trans_table = stat->freq_table + count;
243#endif
244	j = 0;
245	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
246		unsigned int freq = table[i].frequency;
247		if (freq == CPUFREQ_ENTRY_INVALID)
248			continue;
249		if (freq_table_get_index(stat, freq) == -1)
250			stat->freq_table[j++] = freq;
251	}
252	stat->state_num = j;
253	spin_lock(&cpufreq_stats_lock);
254	stat->last_time = get_jiffies_64();
255	stat->last_index = freq_table_get_index(stat, policy->cur);
256	spin_unlock(&cpufreq_stats_lock);
257	cpufreq_cpu_put(data);
258	return 0;
259error_out:
260	cpufreq_cpu_put(data);
261error_get_fail:
262	kfree(stat);
263	per_cpu(cpufreq_stats_table, cpu) = NULL;
264	return ret;
265}
266
267static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
268		unsigned long val, void *data)
269{
270	int ret;
271	struct cpufreq_policy *policy = data;
272	struct cpufreq_frequency_table *table;
273	unsigned int cpu = policy->cpu;
274	if (val != CPUFREQ_NOTIFY)
275		return 0;
276	table = cpufreq_frequency_get_table(cpu);
277	if (!table)
278		return 0;
279	ret = cpufreq_stats_create_table(policy, table);
280	if (ret)
281		return ret;
282	return 0;
283}
284
285static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
286		unsigned long val, void *data)
287{
288	struct cpufreq_freqs *freq = data;
289	struct cpufreq_stats *stat;
290	int old_index, new_index;
291
292	if (val != CPUFREQ_POSTCHANGE)
293		return 0;
294
295	stat = per_cpu(cpufreq_stats_table, freq->cpu);
296	if (!stat)
297		return 0;
298
299	old_index = stat->last_index;
300	new_index = freq_table_get_index(stat, freq->new);
301
302	/* We can't do stat->time_in_state[-1]= .. */
303	if (old_index == -1 || new_index == -1)
304		return 0;
305
306	cpufreq_stats_update(freq->cpu);
307
308	if (old_index == new_index)
309		return 0;
310
311	spin_lock(&cpufreq_stats_lock);
312	stat->last_index = new_index;
313#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
314	stat->trans_table[old_index * stat->max_state + new_index]++;
315#endif
316	stat->total_trans++;
317	spin_unlock(&cpufreq_stats_lock);
318	return 0;
319}
320
321static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
322					       unsigned long action,
323					       void *hcpu)
324{
325	unsigned int cpu = (unsigned long)hcpu;
326
327	switch (action) {
328	case CPU_ONLINE:
329	case CPU_ONLINE_FROZEN:
330		cpufreq_update_policy(cpu);
331		break;
332	case CPU_DOWN_PREPARE:
333		cpufreq_stats_free_sysfs(cpu);
334		break;
335	case CPU_DEAD:
336	case CPU_DEAD_FROZEN:
337		cpufreq_stats_free_table(cpu);
338		break;
339	}
340	return NOTIFY_OK;
341}
342
343/* priority=1 so this will get called before cpufreq_remove_dev */
344static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
345	.notifier_call = cpufreq_stat_cpu_callback,
346	.priority = 1,
347};
348
349static struct notifier_block notifier_policy_block = {
350	.notifier_call = cpufreq_stat_notifier_policy
351};
352
353static struct notifier_block notifier_trans_block = {
354	.notifier_call = cpufreq_stat_notifier_trans
355};
356
357static int __init cpufreq_stats_init(void)
358{
359	int ret;
360	unsigned int cpu;
361
362	spin_lock_init(&cpufreq_stats_lock);
363	ret = cpufreq_register_notifier(&notifier_policy_block,
364				CPUFREQ_POLICY_NOTIFIER);
365	if (ret)
366		return ret;
367
368	ret = cpufreq_register_notifier(&notifier_trans_block,
369				CPUFREQ_TRANSITION_NOTIFIER);
370	if (ret) {
371		cpufreq_unregister_notifier(&notifier_policy_block,
372				CPUFREQ_POLICY_NOTIFIER);
373		return ret;
374	}
375
376	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
377	for_each_online_cpu(cpu) {
378		cpufreq_update_policy(cpu);
379	}
380	return 0;
381}
382static void __exit cpufreq_stats_exit(void)
383{
384	unsigned int cpu;
385
386	cpufreq_unregister_notifier(&notifier_policy_block,
387			CPUFREQ_POLICY_NOTIFIER);
388	cpufreq_unregister_notifier(&notifier_trans_block,
389			CPUFREQ_TRANSITION_NOTIFIER);
390	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
391	for_each_online_cpu(cpu) {
392		cpufreq_stats_free_table(cpu);
393		cpufreq_stats_free_sysfs(cpu);
394	}
395}
396
397MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
398MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
399				"through sysfs filesystem");
400MODULE_LICENSE("GPL");
401
402module_init(cpufreq_stats_init);
403module_exit(cpufreq_stats_exit);
404