xref: /linux/drivers/cpufreq/cpufreq_stats.c (revision 033b5650010652c069494df58424c4b98412fe3b) 
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/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 	cputime64_t *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 			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 
71 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
72 {
73 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
74 	if (!stat)
75 		return 0;
76 	return sprintf(buf, "%d\n",
77 			per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
78 }
79 
80 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
81 {
82 	ssize_t len = 0;
83 	int i;
84 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
85 	if (!stat)
86 		return 0;
87 	cpufreq_stats_update(stat->cpu);
88 	for (i = 0; i < stat->state_num; i++) {
89 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
90 			(unsigned long long)
91 			cputime64_to_clock_t(stat->time_in_state[i]));
92 	}
93 	return len;
94 }
95 
96 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
97 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
98 {
99 	ssize_t len = 0;
100 	int i, j;
101 
102 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
103 	if (!stat)
104 		return 0;
105 	cpufreq_stats_update(stat->cpu);
106 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
107 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
108 	for (i = 0; i < stat->state_num; i++) {
109 		if (len >= PAGE_SIZE)
110 			break;
111 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
112 				stat->freq_table[i]);
113 	}
114 	if (len >= PAGE_SIZE)
115 		return PAGE_SIZE;
116 
117 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
118 
119 	for (i = 0; i < stat->state_num; i++) {
120 		if (len >= PAGE_SIZE)
121 			break;
122 
123 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
124 				stat->freq_table[i]);
125 
126 		for (j = 0; j < stat->state_num; j++)   {
127 			if (len >= PAGE_SIZE)
128 				break;
129 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
130 					stat->trans_table[i*stat->max_state+j]);
131 		}
132 		if (len >= PAGE_SIZE)
133 			break;
134 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
135 	}
136 	if (len >= PAGE_SIZE)
137 		return PAGE_SIZE;
138 	return len;
139 }
140 CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
141 #endif
142 
143 CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
144 CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
145 
146 static struct attribute *default_attrs[] = {
147 	&_attr_total_trans.attr,
148 	&_attr_time_in_state.attr,
149 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
150 	&_attr_trans_table.attr,
151 #endif
152 	NULL
153 };
154 static struct attribute_group stats_attr_group = {
155 	.attrs = default_attrs,
156 	.name = "stats"
157 };
158 
159 static int 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 /* should be called late in the CPU removal sequence so that the stats
169  * memory is still available in case someone tries to use it.
170  */
171 static void cpufreq_stats_free_table(unsigned int cpu)
172 {
173 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
174 	if (stat) {
175 		kfree(stat->time_in_state);
176 		kfree(stat);
177 	}
178 	per_cpu(cpufreq_stats_table, cpu) = NULL;
179 }
180 
181 /* must be called early in the CPU removal sequence (before
182  * cpufreq_remove_dev) so that policy is still valid.
183  */
184 static void cpufreq_stats_free_sysfs(unsigned int cpu)
185 {
186 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
187 	if (policy && policy->cpu == cpu)
188 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
189 	if (policy)
190 		cpufreq_cpu_put(policy);
191 }
192 
193 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
194 		struct cpufreq_frequency_table *table)
195 {
196 	unsigned int i, j, count = 0, ret = 0;
197 	struct cpufreq_stats *stat;
198 	struct cpufreq_policy *data;
199 	unsigned int alloc_size;
200 	unsigned int cpu = policy->cpu;
201 	if (per_cpu(cpufreq_stats_table, cpu))
202 		return -EBUSY;
203 	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
204 	if ((stat) == NULL)
205 		return -ENOMEM;
206 
207 	data = cpufreq_cpu_get(cpu);
208 	if (data == NULL) {
209 		ret = -EINVAL;
210 		goto error_get_fail;
211 	}
212 
213 	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
214 	if (ret)
215 		goto error_out;
216 
217 	stat->cpu = cpu;
218 	per_cpu(cpufreq_stats_table, cpu) = stat;
219 
220 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
221 		unsigned int freq = table[i].frequency;
222 		if (freq == CPUFREQ_ENTRY_INVALID)
223 			continue;
224 		count++;
225 	}
226 
227 	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
228 
229 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
230 	alloc_size += count * count * sizeof(int);
231 #endif
232 	stat->max_state = count;
233 	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
234 	if (!stat->time_in_state) {
235 		ret = -ENOMEM;
236 		goto error_out;
237 	}
238 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
239 
240 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
241 	stat->trans_table = stat->freq_table + count;
242 #endif
243 	j = 0;
244 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
245 		unsigned int freq = table[i].frequency;
246 		if (freq == CPUFREQ_ENTRY_INVALID)
247 			continue;
248 		if (freq_table_get_index(stat, freq) == -1)
249 			stat->freq_table[j++] = freq;
250 	}
251 	stat->state_num = j;
252 	spin_lock(&cpufreq_stats_lock);
253 	stat->last_time = get_jiffies_64();
254 	stat->last_index = freq_table_get_index(stat, policy->cur);
255 	spin_unlock(&cpufreq_stats_lock);
256 	cpufreq_cpu_put(data);
257 	return 0;
258 error_out:
259 	cpufreq_cpu_put(data);
260 error_get_fail:
261 	kfree(stat);
262 	per_cpu(cpufreq_stats_table, cpu) = NULL;
263 	return ret;
264 }
265 
266 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
267 		unsigned long val, void *data)
268 {
269 	int ret;
270 	struct cpufreq_policy *policy = data;
271 	struct cpufreq_frequency_table *table;
272 	unsigned int cpu = policy->cpu;
273 	if (val != CPUFREQ_NOTIFY)
274 		return 0;
275 	table = cpufreq_frequency_get_table(cpu);
276 	if (!table)
277 		return 0;
278 	ret = cpufreq_stats_create_table(policy, table);
279 	if (ret)
280 		return ret;
281 	return 0;
282 }
283 
284 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
285 		unsigned long val, void *data)
286 {
287 	struct cpufreq_freqs *freq = data;
288 	struct cpufreq_stats *stat;
289 	int old_index, new_index;
290 
291 	if (val != CPUFREQ_POSTCHANGE)
292 		return 0;
293 
294 	stat = per_cpu(cpufreq_stats_table, freq->cpu);
295 	if (!stat)
296 		return 0;
297 
298 	old_index = stat->last_index;
299 	new_index = freq_table_get_index(stat, freq->new);
300 
301 	/* We can't do stat->time_in_state[-1]= .. */
302 	if (old_index == -1 || new_index == -1)
303 		return 0;
304 
305 	cpufreq_stats_update(freq->cpu);
306 
307 	if (old_index == new_index)
308 		return 0;
309 
310 	spin_lock(&cpufreq_stats_lock);
311 	stat->last_index = new_index;
312 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
313 	stat->trans_table[old_index * stat->max_state + new_index]++;
314 #endif
315 	stat->total_trans++;
316 	spin_unlock(&cpufreq_stats_lock);
317 	return 0;
318 }
319 
320 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
321 					       unsigned long action,
322 					       void *hcpu)
323 {
324 	unsigned int cpu = (unsigned long)hcpu;
325 
326 	switch (action) {
327 	case CPU_ONLINE:
328 	case CPU_ONLINE_FROZEN:
329 		cpufreq_update_policy(cpu);
330 		break;
331 	case CPU_DOWN_PREPARE:
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