summaryrefslogtreecommitdiff
path: root/drivers/cpufreq/cpufreq_stats.c
blob: c948086a332bae702a5a6fc20b14a409e3d21f4f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/*
 *  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/cpu.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/cputime.h>

static spinlock_t cpufreq_stats_lock;

struct cpufreq_stats {
	unsigned int total_trans;
	unsigned long long last_time;
	unsigned int max_state;
	unsigned int state_num;
	unsigned int last_index;
	u64 *time_in_state;
	unsigned int *freq_table;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	unsigned int *trans_table;
#endif
};

static int cpufreq_stats_update(struct cpufreq_stats *stats)
{
	unsigned long long cur_time = get_jiffies_64();

	spin_lock(&cpufreq_stats_lock);
	stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
	stats->last_time = cur_time;
	spin_unlock(&cpufreq_stats_lock);
	return 0;
}

static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
{
	return sprintf(buf, "%d\n", policy->stats->total_trans);
}

static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
{
	struct cpufreq_stats *stats = policy->stats;
	ssize_t len = 0;
	int i;

	cpufreq_stats_update(stats);
	for (i = 0; i < stats->state_num; i++) {
		len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
			(unsigned long long)
			jiffies_64_to_clock_t(stats->time_in_state[i]));
	}
	return len;
}

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

	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
	for (i = 0; i < stats->state_num; i++) {
		if (len >= PAGE_SIZE)
			break;
		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
				stats->freq_table[i]);
	}
	if (len >= PAGE_SIZE)
		return PAGE_SIZE;

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

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

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

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

cpufreq_freq_attr_ro(total_trans);
cpufreq_freq_attr_ro(time_in_state);

static struct attribute *default_attrs[] = {
	&total_trans.attr,
	&time_in_state.attr,
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	&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 *stats, unsigned int freq)
{
	int index;
	for (index = 0; index < stats->max_state; index++)
		if (stats->freq_table[index] == freq)
			return index;
	return -1;
}

static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
{
	struct cpufreq_stats *stats = policy->stats;

	/* Already freed */
	if (!stats)
		return;

	pr_debug("%s: Free stats table\n", __func__);

	sysfs_remove_group(&policy->kobj, &stats_attr_group);
	kfree(stats->time_in_state);
	kfree(stats);
	policy->stats = NULL;
}

static void cpufreq_stats_free_table(unsigned int cpu)
{
	struct cpufreq_policy *policy;

	policy = cpufreq_cpu_get(cpu);
	if (!policy)
		return;

	__cpufreq_stats_free_table(policy);

	cpufreq_cpu_put(policy);
}

static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
{
	unsigned int i = 0, count = 0, ret = -ENOMEM;
	struct cpufreq_stats *stats;
	unsigned int alloc_size;
	unsigned int cpu = policy->cpu;
	struct cpufreq_frequency_table *pos, *table;

	/* We need cpufreq table for creating stats table */
	table = cpufreq_frequency_get_table(cpu);
	if (unlikely(!table))
		return 0;

	/* stats already initialized */
	if (policy->stats)
		return -EEXIST;

	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
	if (!stats)
		return -ENOMEM;

	/* Find total allocation size */
	cpufreq_for_each_valid_entry(pos, table)
		count++;

	alloc_size = count * sizeof(int) + count * sizeof(u64);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	alloc_size += count * count * sizeof(int);
#endif

	/* Allocate memory for time_in_state/freq_table/trans_table in one go */
	stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
	if (!stats->time_in_state)
		goto free_stat;

	stats->freq_table = (unsigned int *)(stats->time_in_state + count);

#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
	stats->trans_table = stats->freq_table + count;
#endif

	stats->max_state = count;

	/* Find valid-unique entries */
	cpufreq_for_each_valid_entry(pos, table)
		if (freq_table_get_index(stats, pos->frequency) == -1)
			stats->freq_table[i++] = pos->frequency;
	stats->state_num = i;

	spin_lock(&cpufreq_stats_lock);
	stats->last_time = get_jiffies_64();
	stats->last_index = freq_table_get_index(stats, policy->cur);
	spin_unlock(&cpufreq_stats_lock);

	policy->stats = stats;
	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
	if (!ret)
		return 0;

	/* We failed, release resources */
	policy->stats = NULL;
	kfree(stats->time_in_state);
free_stat:
	kfree(stats);

	return ret;
}

static void cpufreq_stats_create_table(unsigned int cpu)
{
	struct cpufreq_policy *policy;

	/*
	 * "likely(!policy)" because normally cpufreq_stats will be registered
	 * before cpufreq driver
	 */
	policy = cpufreq_cpu_get(cpu);
	if (likely(!policy))
		return;

	__cpufreq_stats_create_table(policy);

	cpufreq_cpu_put(policy);
}

static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
		unsigned long val, void *data)
{
	int ret = 0;
	struct cpufreq_policy *policy = data;

	if (val == CPUFREQ_CREATE_POLICY)
		ret = __cpufreq_stats_create_table(policy);
	else if (val == CPUFREQ_REMOVE_POLICY)
		__cpufreq_stats_free_table(policy);

	return ret;
}

static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
		unsigned long val, void *data)
{
	struct cpufreq_freqs *freq = data;
	struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
	struct cpufreq_stats *stats;
	int old_index, new_index;

	if (!policy) {
		pr_err("%s: No policy found\n", __func__);
		return 0;
	}

	if (val != CPUFREQ_POSTCHANGE)
		goto put_policy;

	if (!policy->stats) {
		pr_debug("%s: No stats found\n", __func__);
		goto put_policy;
	}

	stats = policy->stats;

	old_index = stats->last_index;
	new_index = freq_table_get_index(stats, freq->new);

	/* We can't do stats->time_in_state[-1]= .. */
	if (old_index == -1 || new_index == -1)
		goto put_policy;

	if (old_index == new_index)
		goto put_policy;

	cpufreq_stats_update(stats);

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

put_policy:
	cpufreq_cpu_put(policy);
	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);
	ret = cpufreq_register_notifier(&notifier_policy_block,
				CPUFREQ_POLICY_NOTIFIER);
	if (ret)
		return ret;

	for_each_online_cpu(cpu)
		cpufreq_stats_create_table(cpu);

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

	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_online_cpu(cpu)
		cpufreq_stats_free_table(cpu);
}

MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
MODULE_LICENSE("GPL");

module_init(cpufreq_stats_init);
module_exit(cpufreq_stats_exit);