xref: /linux/drivers/cpufreq/cpufreq_stats.c (revision 36ca1195ad7f760a6af3814cb002bd3a3d4b4db1)
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>
22 #include <asm/cputime.h>
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 
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 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;
58 	unsigned long long cur_time;
59 
60 	cur_time = get_jiffies_64();
61 	spin_lock(&cpufreq_stats_lock);
62 	stat = 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 
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++) {
92 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
93 			(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
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);
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 
122 	for (i = 0; i < stat->state_num; i++) {
123 		if (len >= PAGE_SIZE)
124 			break;
125 
126 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
127 				stat->freq_table[i]);
128 
129 		for (j = 0; j < stat->state_num; j++)   {
130 			if (len >= PAGE_SIZE)
131 				break;
132 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
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;
195 	if ((stat = kmalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
196 		return -ENOMEM;
197 	memset(stat, 0, sizeof (struct cpufreq_stats));
198 
199 	data = cpufreq_cpu_get(cpu);
200 	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
201 		goto error_out;
202 
203 	stat->cpu = cpu;
204 	cpufreq_stats_table[cpu] = stat;
205 
206 	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
207 		unsigned int freq = table[i].frequency;
208 		if (freq == CPUFREQ_ENTRY_INVALID)
209 			continue;
210 		count++;
211 	}
212 
213 	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
214 
215 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
216 	alloc_size += count * count * sizeof(int);
217 #endif
218 	stat->max_state = count;
219 	stat->time_in_state = kmalloc(alloc_size, GFP_KERNEL);
220 	if (!stat->time_in_state) {
221 		ret = -ENOMEM;
222 		goto error_out;
223 	}
224 	memset(stat->time_in_state, 0, alloc_size);
225 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
226 
227 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
228 	stat->trans_table = stat->freq_table + count;
229 #endif
230 	j = 0;
231 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
232 		unsigned int freq = table[i].frequency;
233 		if (freq == CPUFREQ_ENTRY_INVALID)
234 			continue;
235 		if (freq_table_get_index(stat, freq) == -1)
236 			stat->freq_table[j++] = freq;
237 	}
238 	stat->state_num = j;
239 	spin_lock(&cpufreq_stats_lock);
240 	stat->last_time = get_jiffies_64();
241 	stat->last_index = freq_table_get_index(stat, policy->cur);
242 	spin_unlock(&cpufreq_stats_lock);
243 	cpufreq_cpu_put(data);
244 	return 0;
245 error_out:
246 	cpufreq_cpu_put(data);
247 	kfree(stat);
248 	cpufreq_stats_table[cpu] = NULL;
249 	return ret;
250 }
251 
252 static int
253 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
254 		void *data)
255 {
256 	int ret;
257 	struct cpufreq_policy *policy = data;
258 	struct cpufreq_frequency_table *table;
259 	unsigned int cpu = policy->cpu;
260 	if (val != CPUFREQ_NOTIFY)
261 		return 0;
262 	table = cpufreq_frequency_get_table(cpu);
263 	if (!table)
264 		return 0;
265 	if ((ret = cpufreq_stats_create_table(policy, table)))
266 		return ret;
267 	return 0;
268 }
269 
270 static int
271 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
272 		void *data)
273 {
274 	struct cpufreq_freqs *freq = data;
275 	struct cpufreq_stats *stat;
276 	int old_index, new_index;
277 
278 	if (val != CPUFREQ_POSTCHANGE)
279 		return 0;
280 
281 	stat = cpufreq_stats_table[freq->cpu];
282 	if (!stat)
283 		return 0;
284 	old_index = freq_table_get_index(stat, freq->old);
285 	new_index = freq_table_get_index(stat, freq->new);
286 
287 	cpufreq_stats_update(freq->cpu);
288 	if (old_index == new_index)
289 		return 0;
290 
291 	spin_lock(&cpufreq_stats_lock);
292 	stat->last_index = new_index;
293 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
294 	stat->trans_table[old_index * stat->max_state + new_index]++;
295 #endif
296 	stat->total_trans++;
297 	spin_unlock(&cpufreq_stats_lock);
298 	return 0;
299 }
300 
301 static struct notifier_block notifier_policy_block = {
302 	.notifier_call = cpufreq_stat_notifier_policy
303 };
304 
305 static struct notifier_block notifier_trans_block = {
306 	.notifier_call = cpufreq_stat_notifier_trans
307 };
308 
309 static int
310 __init cpufreq_stats_init(void)
311 {
312 	int ret;
313 	unsigned int cpu;
314 	spin_lock_init(&cpufreq_stats_lock);
315 	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
316 				CPUFREQ_POLICY_NOTIFIER)))
317 		return ret;
318 
319 	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
320 				CPUFREQ_TRANSITION_NOTIFIER))) {
321 		cpufreq_unregister_notifier(&notifier_policy_block,
322 				CPUFREQ_POLICY_NOTIFIER);
323 		return ret;
324 	}
325 
326 	for_each_cpu(cpu)
327 		cpufreq_update_policy(cpu);
328 	return 0;
329 }
330 static void
331 __exit cpufreq_stats_exit(void)
332 {
333 	unsigned int cpu;
334 	cpufreq_unregister_notifier(&notifier_policy_block,
335 			CPUFREQ_POLICY_NOTIFIER);
336 	cpufreq_unregister_notifier(&notifier_trans_block,
337 			CPUFREQ_TRANSITION_NOTIFIER);
338 	for_each_cpu(cpu)
339 		cpufreq_stats_free_table(cpu);
340 }
341 
342 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
343 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
344 MODULE_LICENSE ("GPL");
345 
346 module_init(cpufreq_stats_init);
347 module_exit(cpufreq_stats_exit);
348