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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 | struct cpufreq_stats { |
28 | unsigned int cpu; |
29 | unsigned int total_trans; |
30 | unsigned long long last_time; |
31 | unsigned int max_state; |
32 | unsigned int state_num; |
33 | unsigned int last_index; |
34 | u64 *time_in_state; |
35 | unsigned int *freq_table; |
36 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
37 | unsigned int *trans_table; |
38 | #endif |
39 | }; |
40 | |
41 | static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table); |
42 | |
43 | struct cpufreq_stats_attribute { |
44 | struct attribute attr; |
45 | ssize_t(*show) (struct cpufreq_stats *, char *); |
46 | }; |
47 | |
48 | static int cpufreq_stats_update(unsigned int cpu) |
49 | { |
50 | struct cpufreq_stats *stat; |
51 | unsigned long long cur_time; |
52 | |
53 | cur_time = get_jiffies_64(); |
54 | spin_lock(&cpufreq_stats_lock); |
55 | stat = per_cpu(cpufreq_stats_table, cpu); |
56 | if (stat->time_in_state) |
57 | stat->time_in_state[stat->last_index] += |
58 | cur_time - stat->last_time; |
59 | stat->last_time = cur_time; |
60 | spin_unlock(&cpufreq_stats_lock); |
61 | return 0; |
62 | } |
63 | |
64 | static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) |
65 | { |
66 | struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu); |
67 | if (!stat) |
68 | return 0; |
69 | return sprintf(buf, "%d\n", |
70 | per_cpu(cpufreq_stats_table, stat->cpu)->total_trans); |
71 | } |
72 | |
73 | static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) |
74 | { |
75 | ssize_t len = 0; |
76 | int i; |
77 | struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu); |
78 | if (!stat) |
79 | return 0; |
80 | cpufreq_stats_update(stat->cpu); |
81 | for (i = 0; i < stat->state_num; i++) { |
82 | len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i], |
83 | (unsigned long long) |
84 | cputime64_to_clock_t(stat->time_in_state[i])); |
85 | } |
86 | return len; |
87 | } |
88 | |
89 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
90 | static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf) |
91 | { |
92 | ssize_t len = 0; |
93 | int i, j; |
94 | |
95 | struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu); |
96 | if (!stat) |
97 | return 0; |
98 | cpufreq_stats_update(stat->cpu); |
99 | len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); |
100 | len += snprintf(buf + len, PAGE_SIZE - len, " : "); |
101 | for (i = 0; i < stat->state_num; i++) { |
102 | if (len >= PAGE_SIZE) |
103 | break; |
104 | len += snprintf(buf + len, PAGE_SIZE - len, "%9u ", |
105 | stat->freq_table[i]); |
106 | } |
107 | if (len >= PAGE_SIZE) |
108 | return PAGE_SIZE; |
109 | |
110 | len += snprintf(buf + len, PAGE_SIZE - len, "\n"); |
111 | |
112 | for (i = 0; i < stat->state_num; i++) { |
113 | if (len >= PAGE_SIZE) |
114 | break; |
115 | |
116 | len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ", |
117 | stat->freq_table[i]); |
118 | |
119 | for (j = 0; j < stat->state_num; j++) { |
120 | if (len >= PAGE_SIZE) |
121 | break; |
122 | len += snprintf(buf + len, PAGE_SIZE - len, "%9u ", |
123 | stat->trans_table[i*stat->max_state+j]); |
124 | } |
125 | if (len >= PAGE_SIZE) |
126 | break; |
127 | len += snprintf(buf + len, PAGE_SIZE - len, "\n"); |
128 | } |
129 | if (len >= PAGE_SIZE) |
130 | return PAGE_SIZE; |
131 | return len; |
132 | } |
133 | cpufreq_freq_attr_ro(trans_table); |
134 | #endif |
135 | |
136 | cpufreq_freq_attr_ro(total_trans); |
137 | cpufreq_freq_attr_ro(time_in_state); |
138 | |
139 | static struct attribute *default_attrs[] = { |
140 | &total_trans.attr, |
141 | &time_in_state.attr, |
142 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
143 | &trans_table.attr, |
144 | #endif |
145 | NULL |
146 | }; |
147 | static struct attribute_group stats_attr_group = { |
148 | .attrs = default_attrs, |
149 | .name = "stats" |
150 | }; |
151 | |
152 | static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq) |
153 | { |
154 | int index; |
155 | for (index = 0; index < stat->max_state; index++) |
156 | if (stat->freq_table[index] == freq) |
157 | return index; |
158 | return -1; |
159 | } |
160 | |
161 | /* should be called late in the CPU removal sequence so that the stats |
162 | * memory is still available in case someone tries to use it. |
163 | */ |
164 | static void cpufreq_stats_free_table(unsigned int cpu) |
165 | { |
166 | struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu); |
167 | |
168 | if (stat) { |
169 | pr_debug("%s: Free stat table\n", __func__); |
170 | kfree(stat->time_in_state); |
171 | kfree(stat); |
172 | per_cpu(cpufreq_stats_table, cpu) = NULL; |
173 | } |
174 | } |
175 | |
176 | /* must be called early in the CPU removal sequence (before |
177 | * cpufreq_remove_dev) so that policy is still valid. |
178 | */ |
179 | static void cpufreq_stats_free_sysfs(unsigned int cpu) |
180 | { |
181 | struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); |
182 | |
183 | if (!policy) |
184 | return; |
185 | |
186 | if (!cpufreq_frequency_get_table(cpu)) |
187 | goto put_ref; |
188 | |
189 | if (!policy_is_shared(policy)) { |
190 | pr_debug("%s: Free sysfs stat\n", __func__); |
191 | sysfs_remove_group(&policy->kobj, &stats_attr_group); |
192 | } |
193 | |
194 | put_ref: |
195 | cpufreq_cpu_put(policy); |
196 | } |
197 | |
198 | static int cpufreq_stats_create_table(struct cpufreq_policy *policy, |
199 | struct cpufreq_frequency_table *table) |
200 | { |
201 | unsigned int i, j, count = 0, ret = 0; |
202 | struct cpufreq_stats *stat; |
203 | struct cpufreq_policy *data; |
204 | unsigned int alloc_size; |
205 | unsigned int cpu = policy->cpu; |
206 | if (per_cpu(cpufreq_stats_table, cpu)) |
207 | return -EBUSY; |
208 | stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL); |
209 | if ((stat) == NULL) |
210 | return -ENOMEM; |
211 | |
212 | data = cpufreq_cpu_get(cpu); |
213 | if (data == NULL) { |
214 | ret = -EINVAL; |
215 | goto error_get_fail; |
216 | } |
217 | |
218 | ret = sysfs_create_group(&data->kobj, &stats_attr_group); |
219 | if (ret) |
220 | goto error_out; |
221 | |
222 | stat->cpu = cpu; |
223 | per_cpu(cpufreq_stats_table, cpu) = stat; |
224 | |
225 | for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { |
226 | unsigned int freq = table[i].frequency; |
227 | if (freq == CPUFREQ_ENTRY_INVALID) |
228 | continue; |
229 | count++; |
230 | } |
231 | |
232 | alloc_size = count * sizeof(int) + count * sizeof(u64); |
233 | |
234 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
235 | alloc_size += count * count * sizeof(int); |
236 | #endif |
237 | stat->max_state = count; |
238 | stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL); |
239 | if (!stat->time_in_state) { |
240 | ret = -ENOMEM; |
241 | goto error_out; |
242 | } |
243 | stat->freq_table = (unsigned int *)(stat->time_in_state + count); |
244 | |
245 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
246 | stat->trans_table = stat->freq_table + count; |
247 | #endif |
248 | j = 0; |
249 | for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { |
250 | unsigned int freq = table[i].frequency; |
251 | if (freq == CPUFREQ_ENTRY_INVALID) |
252 | continue; |
253 | if (freq_table_get_index(stat, freq) == -1) |
254 | stat->freq_table[j++] = freq; |
255 | } |
256 | stat->state_num = j; |
257 | spin_lock(&cpufreq_stats_lock); |
258 | stat->last_time = get_jiffies_64(); |
259 | stat->last_index = freq_table_get_index(stat, policy->cur); |
260 | spin_unlock(&cpufreq_stats_lock); |
261 | cpufreq_cpu_put(data); |
262 | return 0; |
263 | error_out: |
264 | cpufreq_cpu_put(data); |
265 | error_get_fail: |
266 | kfree(stat); |
267 | per_cpu(cpufreq_stats_table, cpu) = NULL; |
268 | return ret; |
269 | } |
270 | |
271 | static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy) |
272 | { |
273 | struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, |
274 | policy->last_cpu); |
275 | |
276 | pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n", |
277 | policy->cpu, policy->last_cpu); |
278 | per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table, |
279 | policy->last_cpu); |
280 | per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL; |
281 | stat->cpu = policy->cpu; |
282 | } |
283 | |
284 | static int cpufreq_stat_notifier_policy(struct notifier_block *nb, |
285 | unsigned long val, void *data) |
286 | { |
287 | int ret; |
288 | struct cpufreq_policy *policy = data; |
289 | struct cpufreq_frequency_table *table; |
290 | unsigned int cpu = policy->cpu; |
291 | |
292 | if (val == CPUFREQ_UPDATE_POLICY_CPU) { |
293 | cpufreq_stats_update_policy_cpu(policy); |
294 | return 0; |
295 | } |
296 | |
297 | if (val != CPUFREQ_NOTIFY) |
298 | return 0; |
299 | table = cpufreq_frequency_get_table(cpu); |
300 | if (!table) |
301 | return 0; |
302 | ret = cpufreq_stats_create_table(policy, table); |
303 | if (ret) |
304 | return ret; |
305 | return 0; |
306 | } |
307 | |
308 | static int cpufreq_stat_notifier_trans(struct notifier_block *nb, |
309 | unsigned long val, void *data) |
310 | { |
311 | struct cpufreq_freqs *freq = data; |
312 | struct cpufreq_stats *stat; |
313 | int old_index, new_index; |
314 | |
315 | if (val != CPUFREQ_POSTCHANGE) |
316 | return 0; |
317 | |
318 | stat = per_cpu(cpufreq_stats_table, freq->cpu); |
319 | if (!stat) |
320 | return 0; |
321 | |
322 | old_index = stat->last_index; |
323 | new_index = freq_table_get_index(stat, freq->new); |
324 | |
325 | /* We can't do stat->time_in_state[-1]= .. */ |
326 | if (old_index == -1 || new_index == -1) |
327 | return 0; |
328 | |
329 | cpufreq_stats_update(freq->cpu); |
330 | |
331 | if (old_index == new_index) |
332 | return 0; |
333 | |
334 | spin_lock(&cpufreq_stats_lock); |
335 | stat->last_index = new_index; |
336 | #ifdef CONFIG_CPU_FREQ_STAT_DETAILS |
337 | stat->trans_table[old_index * stat->max_state + new_index]++; |
338 | #endif |
339 | stat->total_trans++; |
340 | spin_unlock(&cpufreq_stats_lock); |
341 | return 0; |
342 | } |
343 | |
344 | static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb, |
345 | unsigned long action, |
346 | void *hcpu) |
347 | { |
348 | unsigned int cpu = (unsigned long)hcpu; |
349 | |
350 | switch (action) { |
351 | case CPU_ONLINE: |
352 | case CPU_ONLINE_FROZEN: |
353 | cpufreq_update_policy(cpu); |
354 | break; |
355 | case CPU_DOWN_PREPARE: |
356 | case CPU_DOWN_PREPARE_FROZEN: |
357 | cpufreq_stats_free_sysfs(cpu); |
358 | break; |
359 | case CPU_DEAD: |
360 | case CPU_DEAD_FROZEN: |
361 | cpufreq_stats_free_table(cpu); |
362 | break; |
363 | } |
364 | return NOTIFY_OK; |
365 | } |
366 | |
367 | /* priority=1 so this will get called before cpufreq_remove_dev */ |
368 | static struct notifier_block cpufreq_stat_cpu_notifier __refdata = { |
369 | .notifier_call = cpufreq_stat_cpu_callback, |
370 | .priority = 1, |
371 | }; |
372 | |
373 | static struct notifier_block notifier_policy_block = { |
374 | .notifier_call = cpufreq_stat_notifier_policy |
375 | }; |
376 | |
377 | static struct notifier_block notifier_trans_block = { |
378 | .notifier_call = cpufreq_stat_notifier_trans |
379 | }; |
380 | |
381 | static int __init cpufreq_stats_init(void) |
382 | { |
383 | int ret; |
384 | unsigned int cpu; |
385 | |
386 | spin_lock_init(&cpufreq_stats_lock); |
387 | ret = cpufreq_register_notifier(¬ifier_policy_block, |
388 | CPUFREQ_POLICY_NOTIFIER); |
389 | if (ret) |
390 | return ret; |
391 | |
392 | register_hotcpu_notifier(&cpufreq_stat_cpu_notifier); |
393 | for_each_online_cpu(cpu) |
394 | cpufreq_update_policy(cpu); |
395 | |
396 | ret = cpufreq_register_notifier(¬ifier_trans_block, |
397 | CPUFREQ_TRANSITION_NOTIFIER); |
398 | if (ret) { |
399 | cpufreq_unregister_notifier(¬ifier_policy_block, |
400 | CPUFREQ_POLICY_NOTIFIER); |
401 | unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier); |
402 | for_each_online_cpu(cpu) |
403 | cpufreq_stats_free_table(cpu); |
404 | return ret; |
405 | } |
406 | |
407 | return 0; |
408 | } |
409 | static void __exit cpufreq_stats_exit(void) |
410 | { |
411 | unsigned int cpu; |
412 | |
413 | cpufreq_unregister_notifier(¬ifier_policy_block, |
414 | CPUFREQ_POLICY_NOTIFIER); |
415 | cpufreq_unregister_notifier(¬ifier_trans_block, |
416 | CPUFREQ_TRANSITION_NOTIFIER); |
417 | unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier); |
418 | for_each_online_cpu(cpu) { |
419 | cpufreq_stats_free_table(cpu); |
420 | cpufreq_stats_free_sysfs(cpu); |
421 | } |
422 | } |
423 | |
424 | MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>"); |
425 | MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats " |
426 | "through sysfs filesystem"); |
427 | MODULE_LICENSE("GPL"); |
428 | |
429 | module_init(cpufreq_stats_init); |
430 | module_exit(cpufreq_stats_exit); |
431 |
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