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 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
cpufreq_stats_update(unsigned int cpu)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
show_total_trans(struct cpufreq_policy * policy,char * buf)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
show_time_in_state(struct cpufreq_policy * policy,char * buf)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
show_trans_table(struct cpufreq_policy * policy,char * buf)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
freq_table_get_index(struct cpufreq_stats * stat,unsigned int freq)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 */
cpufreq_stats_free_table(unsigned int cpu)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 */
cpufreq_stats_free_sysfs(unsigned int cpu)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
cpufreq_stats_create_table(struct cpufreq_policy * policy,struct cpufreq_frequency_table * table)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(cputime64_t);
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
cpufreq_stat_notifier_policy(struct notifier_block * nb,unsigned long val,void * data)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
cpufreq_stat_notifier_trans(struct notifier_block * nb,unsigned long val,void * data)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
cpufreq_stat_cpu_callback(struct notifier_block * nfb,unsigned long action,void * hcpu)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
cpufreq_stats_init(void)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(¬ifier_policy_block,
363 CPUFREQ_POLICY_NOTIFIER);
364 if (ret)
365 return ret;
366
367 ret = cpufreq_register_notifier(¬ifier_trans_block,
368 CPUFREQ_TRANSITION_NOTIFIER);
369 if (ret) {
370 cpufreq_unregister_notifier(¬ifier_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 }
cpufreq_stats_exit(void)381 static void __exit cpufreq_stats_exit(void)
382 {
383 unsigned int cpu;
384
385 cpufreq_unregister_notifier(¬ifier_policy_block,
386 CPUFREQ_POLICY_NOTIFIER);
387 cpufreq_unregister_notifier(¬ifier_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