xref: /linux/drivers/cpufreq/cpufreq_stats.c (revision 4c62e9764ab403d42f9b8871b1241fe7812f19d4) 
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/cpu.h>
15 #include <linux/sysfs.h>
16 #include <linux/cpufreq.h>
17 #include <linux/module.h>
18 #include <linux/jiffies.h>
19 #include <linux/percpu.h>
20 #include <linux/kobject.h>
21 #include <linux/spinlock.h>
22 #include <linux/notifier.h>
23 #include <asm/cputime.h>
24 
25 static spinlock_t cpufreq_stats_lock;
26 
27 #define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
28 static struct freq_attr _attr_##_name = {\
29 	.attr = {.name = __stringify(_name), .mode = _mode, }, \
30 	.show = _show,\
31 };
32 
33 struct cpufreq_stats {
34 	unsigned int cpu;
35 	unsigned int total_trans;
36 	unsigned long long  last_time;
37 	unsigned int max_state;
38 	unsigned int state_num;
39 	unsigned int last_index;
40 	u64 *time_in_state;
41 	unsigned int *freq_table;
42 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
43 	unsigned int *trans_table;
44 #endif
45 };
46 
47 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
48 
49 struct cpufreq_stats_attribute {
50 	struct attribute attr;
51 	ssize_t(*show) (struct cpufreq_stats *, char *);
52 };
53 
54 static int cpufreq_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 			cur_time - stat->last_time;
65 	stat->last_time = cur_time;
66 	spin_unlock(&cpufreq_stats_lock);
67 	return 0;
68 }
69 
70 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
71 {
72 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
73 	if (!stat)
74 		return 0;
75 	return sprintf(buf, "%d\n",
76 			per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
77 }
78 
79 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
80 {
81 	ssize_t len = 0;
82 	int i;
83 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
84 	if (!stat)
85 		return 0;
86 	cpufreq_stats_update(stat->cpu);
87 	for (i = 0; i < stat->state_num; i++) {
88 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
89 			(unsigned long long)
90 			cputime64_to_clock_t(stat->time_in_state[i]));
91 	}
92 	return len;
93 }
94 
95 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
96 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
97 {
98 	ssize_t len = 0;
99 	int i, j;
100 
101 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
102 	if (!stat)
103 		return 0;
104 	cpufreq_stats_update(stat->cpu);
105 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
106 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
107 	for (i = 0; i < stat->state_num; i++) {
108 		if (len >= PAGE_SIZE)
109 			break;
110 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
111 				stat->freq_table[i]);
112 	}
113 	if (len >= PAGE_SIZE)
114 		return PAGE_SIZE;
115 
116 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
117 
118 	for (i = 0; i < stat->state_num; i++) {
119 		if (len >= PAGE_SIZE)
120 			break;
121 
122 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
123 				stat->freq_table[i]);
124 
125 		for (j = 0; j < stat->state_num; j++)   {
126 			if (len >= PAGE_SIZE)
127 				break;
128 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
129 					stat->trans_table[i*stat->max_state+j]);
130 		}
131 		if (len >= PAGE_SIZE)
132 			break;
133 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
134 	}
135 	if (len >= PAGE_SIZE)
136 		return PAGE_SIZE;
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 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
159 {
160 	int index;
161 	for (index = 0; index < stat->max_state; index++)
162 		if (stat->freq_table[index] == freq)
163 			return index;
164 	return -1;
165 }
166 
167 /* should be called late in the CPU removal sequence so that the stats
168  * memory is still available in case someone tries to use it.
169  */
170 static void cpufreq_stats_free_table(unsigned int cpu)
171 {
172 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
173 	if (stat) {
174 		kfree(stat->time_in_state);
175 		kfree(stat);
176 	}
177 	per_cpu(cpufreq_stats_table, cpu) = NULL;
178 }
179 
180 /* must be called early in the CPU removal sequence (before
181  * cpufreq_remove_dev) so that policy is still valid.
182  */
183 static void cpufreq_stats_free_sysfs(unsigned int cpu)
184 {
185 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
186 	if (policy && policy->cpu == cpu)
187 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
188 	if (policy)
189 		cpufreq_cpu_put(policy);
190 }
191 
192 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
193 		struct cpufreq_frequency_table *table)
194 {
195 	unsigned int i, j, count = 0, ret = 0;
196 	struct cpufreq_stats *stat;
197 	struct cpufreq_policy *data;
198 	unsigned int alloc_size;
199 	unsigned int cpu = policy->cpu;
200 	if (per_cpu(cpufreq_stats_table, cpu))
201 		return -EBUSY;
202 	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
203 	if ((stat) == NULL)
204 		return -ENOMEM;
205 
206 	data = cpufreq_cpu_get(cpu);
207 	if (data == NULL) {
208 		ret = -EINVAL;
209 		goto error_get_fail;
210 	}
211 
212 	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
213 	if (ret)
214 		goto error_out;
215 
216 	stat->cpu = cpu;
217 	per_cpu(cpufreq_stats_table, cpu) = stat;
218 
219 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
220 		unsigned int freq = table[i].frequency;
221 		if (freq == CPUFREQ_ENTRY_INVALID)
222 			continue;
223 		count++;
224 	}
225 
226 	alloc_size = count * sizeof(int) + count * sizeof(u64);
227 
228 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
229 	alloc_size += count * count * sizeof(int);
230 #endif
231 	stat->max_state = count;
232 	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
233 	if (!stat->time_in_state) {
234 		ret = -ENOMEM;
235 		goto error_out;
236 	}
237 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
238 
239 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
240 	stat->trans_table = stat->freq_table + count;
241 #endif
242 	j = 0;
243 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
244 		unsigned int freq = table[i].frequency;
245 		if (freq == CPUFREQ_ENTRY_INVALID)
246 			continue;
247 		if (freq_table_get_index(stat, freq) == -1)
248 			stat->freq_table[j++] = freq;
249 	}
250 	stat->state_num = j;
251 	spin_lock(&cpufreq_stats_lock);
252 	stat->last_time = get_jiffies_64();
253 	stat->last_index = freq_table_get_index(stat, policy->cur);
254 	spin_unlock(&cpufreq_stats_lock);
255 	cpufreq_cpu_put(data);
256 	return 0;
257 error_out:
258 	cpufreq_cpu_put(data);
259 error_get_fail:
260 	kfree(stat);
261 	per_cpu(cpufreq_stats_table, cpu) = NULL;
262 	return ret;
263 }
264 
265 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
266 		unsigned long val, void *data)
267 {
268 	int ret;
269 	struct cpufreq_policy *policy = data;
270 	struct cpufreq_frequency_table *table;
271 	unsigned int cpu = policy->cpu;
272 	if (val != CPUFREQ_NOTIFY)
273 		return 0;
274 	table = cpufreq_frequency_get_table(cpu);
275 	if (!table)
276 		return 0;
277 	ret = cpufreq_stats_create_table(policy, table);
278 	if (ret)
279 		return ret;
280 	return 0;
281 }
282 
283 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
284 		unsigned long val, void *data)
285 {
286 	struct cpufreq_freqs *freq = data;
287 	struct cpufreq_stats *stat;
288 	int old_index, new_index;
289 
290 	if (val != CPUFREQ_POSTCHANGE)
291 		return 0;
292 
293 	stat = per_cpu(cpufreq_stats_table, freq->cpu);
294 	if (!stat)
295 		return 0;
296 
297 	old_index = stat->last_index;
298 	new_index = freq_table_get_index(stat, freq->new);
299 
300 	/* We can't do stat->time_in_state[-1]= .. */
301 	if (old_index == -1 || new_index == -1)
302 		return 0;
303 
304 	cpufreq_stats_update(freq->cpu);
305 
306 	if (old_index == new_index)
307 		return 0;
308 
309 	spin_lock(&cpufreq_stats_lock);
310 	stat->last_index = new_index;
311 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
312 	stat->trans_table[old_index * stat->max_state + new_index]++;
313 #endif
314 	stat->total_trans++;
315 	spin_unlock(&cpufreq_stats_lock);
316 	return 0;
317 }
318 
319 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
320 					       unsigned long action,
321 					       void *hcpu)
322 {
323 	unsigned int cpu = (unsigned long)hcpu;
324 
325 	switch (action) {
326 	case CPU_ONLINE:
327 	case CPU_ONLINE_FROZEN:
328 		cpufreq_update_policy(cpu);
329 		break;
330 	case CPU_DOWN_PREPARE:
331 	case CPU_DOWN_PREPARE_FROZEN:
332 		cpufreq_stats_free_sysfs(cpu);
333 		break;
334 	case CPU_DEAD:
335 	case CPU_DEAD_FROZEN:
336 		cpufreq_stats_free_table(cpu);
337 		break;
338 	}
339 	return NOTIFY_OK;
340 }
341 
342 /* priority=1 so this will get called before cpufreq_remove_dev */
343 static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
344 	.notifier_call = cpufreq_stat_cpu_callback,
345 	.priority = 1,
346 };
347 
348 static struct notifier_block notifier_policy_block = {
349 	.notifier_call = cpufreq_stat_notifier_policy
350 };
351 
352 static struct notifier_block notifier_trans_block = {
353 	.notifier_call = cpufreq_stat_notifier_trans
354 };
355 
356 static int __init cpufreq_stats_init(void)
357 {
358 	int ret;
359 	unsigned int cpu;
360 
361 	spin_lock_init(&cpufreq_stats_lock);
362 	ret = cpufreq_register_notifier(&notifier_policy_block,
363 				CPUFREQ_POLICY_NOTIFIER);
364 	if (ret)
365 		return ret;
366 
367 	ret = cpufreq_register_notifier(&notifier_trans_block,
368 				CPUFREQ_TRANSITION_NOTIFIER);
369 	if (ret) {
370 		cpufreq_unregister_notifier(&notifier_policy_block,
371 				CPUFREQ_POLICY_NOTIFIER);
372 		return ret;
373 	}
374 
375 	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
376 	for_each_online_cpu(cpu) {
377 		cpufreq_update_policy(cpu);
378 	}
379 	return 0;
380 }
381 static void __exit cpufreq_stats_exit(void)
382 {
383 	unsigned int cpu;
384 
385 	cpufreq_unregister_notifier(&notifier_policy_block,
386 			CPUFREQ_POLICY_NOTIFIER);
387 	cpufreq_unregister_notifier(&notifier_trans_block,
388 			CPUFREQ_TRANSITION_NOTIFIER);
389 	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
390 	for_each_online_cpu(cpu) {
391 		cpufreq_stats_free_table(cpu);
392 		cpufreq_stats_free_sysfs(cpu);
393 	}
394 }
395 
396 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
397 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
398 				"through sysfs filesystem");
399 MODULE_LICENSE("GPL");
400 
401 module_init(cpufreq_stats_init);
402 module_exit(cpufreq_stats_exit);
403