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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/cpu.h>
13#include <linux/cpufreq.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/cputime.h>
17
18static spinlock_t cpufreq_stats_lock;
19
20struct cpufreq_stats {
21 unsigned int cpu;
22 unsigned int total_trans;
23 unsigned long long last_time;
24 unsigned int max_state;
25 unsigned int state_num;
26 unsigned int last_index;
27 u64 *time_in_state;
28 unsigned int *freq_table;
29#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
30 unsigned int *trans_table;
31#endif
32};
33
34static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
35
36struct cpufreq_stats_attribute {
37 struct attribute attr;
38 ssize_t(*show) (struct cpufreq_stats *, char *);
39};
40
41static int cpufreq_stats_update(unsigned int cpu)
42{
43 struct cpufreq_stats *stat;
44 unsigned long long cur_time;
45
46 cur_time = get_jiffies_64();
47 spin_lock(&cpufreq_stats_lock);
48 stat = per_cpu(cpufreq_stats_table, cpu);
49 if (stat->time_in_state)
50 stat->time_in_state[stat->last_index] +=
51 cur_time - stat->last_time;
52 stat->last_time = cur_time;
53 spin_unlock(&cpufreq_stats_lock);
54 return 0;
55}
56
57static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
58{
59 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
60 if (!stat)
61 return 0;
62 return sprintf(buf, "%d\n",
63 per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
64}
65
66static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
67{
68 ssize_t len = 0;
69 int i;
70 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
71 if (!stat)
72 return 0;
73 cpufreq_stats_update(stat->cpu);
74 for (i = 0; i < stat->state_num; i++) {
75 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
76 (unsigned long long)
77 jiffies_64_to_clock_t(stat->time_in_state[i]));
78 }
79 return len;
80}
81
82#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
83static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
84{
85 ssize_t len = 0;
86 int i, j;
87
88 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
89 if (!stat)
90 return 0;
91 cpufreq_stats_update(stat->cpu);
92 len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
93 len += snprintf(buf + len, PAGE_SIZE - len, " : ");
94 for (i = 0; i < stat->state_num; i++) {
95 if (len >= PAGE_SIZE)
96 break;
97 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
98 stat->freq_table[i]);
99 }
100 if (len >= PAGE_SIZE)
101 return PAGE_SIZE;
102
103 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
104
105 for (i = 0; i < stat->state_num; i++) {
106 if (len >= PAGE_SIZE)
107 break;
108
109 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
110 stat->freq_table[i]);
111
112 for (j = 0; j < stat->state_num; j++) {
113 if (len >= PAGE_SIZE)
114 break;
115 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
116 stat->trans_table[i*stat->max_state+j]);
117 }
118 if (len >= PAGE_SIZE)
119 break;
120 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
121 }
122 if (len >= PAGE_SIZE)
123 return PAGE_SIZE;
124 return len;
125}
126cpufreq_freq_attr_ro(trans_table);
127#endif
128
129cpufreq_freq_attr_ro(total_trans);
130cpufreq_freq_attr_ro(time_in_state);
131
132static struct attribute *default_attrs[] = {
133 &total_trans.attr,
134 &time_in_state.attr,
135#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
136 &trans_table.attr,
137#endif
138 NULL
139};
140static struct attribute_group stats_attr_group = {
141 .attrs = default_attrs,
142 .name = "stats"
143};
144
145static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
146{
147 int index;
148 for (index = 0; index < stat->max_state; index++)
149 if (stat->freq_table[index] == freq)
150 return index;
151 return -1;
152}
153
154static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
155{
156 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
157
158 if (!stat)
159 return;
160
161 pr_debug("%s: Free stat table\n", __func__);
162
163 sysfs_remove_group(&policy->kobj, &stats_attr_group);
164 kfree(stat->time_in_state);
165 kfree(stat);
166 per_cpu(cpufreq_stats_table, policy->cpu) = NULL;
167}
168
169static void cpufreq_stats_free_table(unsigned int cpu)
170{
171 struct cpufreq_policy *policy;
172
173 policy = cpufreq_cpu_get(cpu);
174 if (!policy)
175 return;
176
177 if (cpufreq_frequency_get_table(policy->cpu))
178 __cpufreq_stats_free_table(policy);
179
180 cpufreq_cpu_put(policy);
181}
182
183static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
184{
185 unsigned int i, j, count = 0, ret = 0;
186 struct cpufreq_stats *stat;
187 unsigned int alloc_size;
188 unsigned int cpu = policy->cpu;
189 struct cpufreq_frequency_table *table;
190
191 table = cpufreq_frequency_get_table(cpu);
192 if (unlikely(!table))
193 return 0;
194
195 if (per_cpu(cpufreq_stats_table, cpu))
196 return -EBUSY;
197 stat = kzalloc(sizeof(*stat), GFP_KERNEL);
198 if ((stat) == NULL)
199 return -ENOMEM;
200
201 ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
202 if (ret)
203 goto error_out;
204
205 stat->cpu = cpu;
206 per_cpu(cpufreq_stats_table, cpu) = stat;
207
208 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
209 unsigned int freq = table[i].frequency;
210 if (freq == CPUFREQ_ENTRY_INVALID)
211 continue;
212 count++;
213 }
214
215 alloc_size = count * sizeof(int) + count * sizeof(u64);
216
217#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
218 alloc_size += count * count * sizeof(int);
219#endif
220 stat->max_state = count;
221 stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
222 if (!stat->time_in_state) {
223 ret = -ENOMEM;
224 goto error_alloc;
225 }
226 stat->freq_table = (unsigned int *)(stat->time_in_state + count);
227
228#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
229 stat->trans_table = stat->freq_table + count;
230#endif
231 j = 0;
232 for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
233 unsigned int freq = table[i].frequency;
234 if (freq == CPUFREQ_ENTRY_INVALID)
235 continue;
236 if (freq_table_get_index(stat, freq) == -1)
237 stat->freq_table[j++] = freq;
238 }
239 stat->state_num = j;
240 spin_lock(&cpufreq_stats_lock);
241 stat->last_time = get_jiffies_64();
242 stat->last_index = freq_table_get_index(stat, policy->cur);
243 spin_unlock(&cpufreq_stats_lock);
244 return 0;
245error_alloc:
246 sysfs_remove_group(&policy->kobj, &stats_attr_group);
247error_out:
248 kfree(stat);
249 per_cpu(cpufreq_stats_table, cpu) = NULL;
250 return ret;
251}
252
253static void cpufreq_stats_create_table(unsigned int cpu)
254{
255 struct cpufreq_policy *policy;
256
257 /*
258 * "likely(!policy)" because normally cpufreq_stats will be registered
259 * before cpufreq driver
260 */
261 policy = cpufreq_cpu_get(cpu);
262 if (likely(!policy))
263 return;
264
265 __cpufreq_stats_create_table(policy);
266
267 cpufreq_cpu_put(policy);
268}
269
270static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
271{
272 struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
273 policy->last_cpu);
274
275 pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
276 policy->cpu, policy->last_cpu);
277 per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
278 policy->last_cpu);
279 per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
280 stat->cpu = policy->cpu;
281}
282
283static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
284 unsigned long val, void *data)
285{
286 int ret = 0;
287 struct cpufreq_policy *policy = data;
288
289 if (val == CPUFREQ_UPDATE_POLICY_CPU) {
290 cpufreq_stats_update_policy_cpu(policy);
291 return 0;
292 }
293
294 if (val == CPUFREQ_CREATE_POLICY)
295 ret = __cpufreq_stats_create_table(policy);
296 else if (val == CPUFREQ_REMOVE_POLICY)
297 __cpufreq_stats_free_table(policy);
298
299 return ret;
300}
301
302static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
303 unsigned long val, void *data)
304{
305 struct cpufreq_freqs *freq = data;
306 struct cpufreq_stats *stat;
307 int old_index, new_index;
308
309 if (val != CPUFREQ_POSTCHANGE)
310 return 0;
311
312 stat = per_cpu(cpufreq_stats_table, freq->cpu);
313 if (!stat)
314 return 0;
315
316 old_index = stat->last_index;
317 new_index = freq_table_get_index(stat, freq->new);
318
319 /* We can't do stat->time_in_state[-1]= .. */
320 if (old_index == -1 || new_index == -1)
321 return 0;
322
323 cpufreq_stats_update(freq->cpu);
324
325 if (old_index == new_index)
326 return 0;
327
328 spin_lock(&cpufreq_stats_lock);
329 stat->last_index = new_index;
330#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
331 stat->trans_table[old_index * stat->max_state + new_index]++;
332#endif
333 stat->total_trans++;
334 spin_unlock(&cpufreq_stats_lock);
335 return 0;
336}
337
338static struct notifier_block notifier_policy_block = {
339 .notifier_call = cpufreq_stat_notifier_policy
340};
341
342static struct notifier_block notifier_trans_block = {
343 .notifier_call = cpufreq_stat_notifier_trans
344};
345
346static int __init cpufreq_stats_init(void)
347{
348 int ret;
349 unsigned int cpu;
350
351 spin_lock_init(&cpufreq_stats_lock);
352 ret = cpufreq_register_notifier(¬ifier_policy_block,
353 CPUFREQ_POLICY_NOTIFIER);
354 if (ret)
355 return ret;
356
357 for_each_online_cpu(cpu)
358 cpufreq_stats_create_table(cpu);
359
360 ret = cpufreq_register_notifier(¬ifier_trans_block,
361 CPUFREQ_TRANSITION_NOTIFIER);
362 if (ret) {
363 cpufreq_unregister_notifier(¬ifier_policy_block,
364 CPUFREQ_POLICY_NOTIFIER);
365 for_each_online_cpu(cpu)
366 cpufreq_stats_free_table(cpu);
367 return ret;
368 }
369
370 return 0;
371}
372static void __exit cpufreq_stats_exit(void)
373{
374 unsigned int cpu;
375
376 cpufreq_unregister_notifier(¬ifier_policy_block,
377 CPUFREQ_POLICY_NOTIFIER);
378 cpufreq_unregister_notifier(¬ifier_trans_block,
379 CPUFREQ_TRANSITION_NOTIFIER);
380 for_each_online_cpu(cpu)
381 cpufreq_stats_free_table(cpu);
382}
383
384MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
385MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
386 "through sysfs filesystem");
387MODULE_LICENSE("GPL");
388
389module_init(cpufreq_stats_init);
390module_exit(cpufreq_stats_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/cpufreq/cpufreq_stats.c
4 *
5 * Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
7 */
8
9#include <linux/cpu.h>
10#include <linux/cpufreq.h>
11#include <linux/module.h>
12#include <linux/sched/clock.h>
13#include <linux/slab.h>
14
15struct cpufreq_stats {
16 unsigned int total_trans;
17 unsigned long long last_time;
18 unsigned int max_state;
19 unsigned int state_num;
20 unsigned int last_index;
21 u64 *time_in_state;
22 unsigned int *freq_table;
23 unsigned int *trans_table;
24
25 /* Deferred reset */
26 unsigned int reset_pending;
27 unsigned long long reset_time;
28};
29
30static void cpufreq_stats_update(struct cpufreq_stats *stats,
31 unsigned long long time)
32{
33 unsigned long long cur_time = local_clock();
34
35 stats->time_in_state[stats->last_index] += cur_time - time;
36 stats->last_time = cur_time;
37}
38
39static void cpufreq_stats_reset_table(struct cpufreq_stats *stats)
40{
41 unsigned int count = stats->max_state;
42
43 memset(stats->time_in_state, 0, count * sizeof(u64));
44 memset(stats->trans_table, 0, count * count * sizeof(int));
45 stats->last_time = local_clock();
46 stats->total_trans = 0;
47
48 /* Adjust for the time elapsed since reset was requested */
49 WRITE_ONCE(stats->reset_pending, 0);
50 /*
51 * Prevent the reset_time read from being reordered before the
52 * reset_pending accesses in cpufreq_stats_record_transition().
53 */
54 smp_rmb();
55 cpufreq_stats_update(stats, READ_ONCE(stats->reset_time));
56}
57
58static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
59{
60 struct cpufreq_stats *stats = policy->stats;
61
62 if (READ_ONCE(stats->reset_pending))
63 return sprintf(buf, "%d\n", 0);
64 else
65 return sprintf(buf, "%u\n", stats->total_trans);
66}
67cpufreq_freq_attr_ro(total_trans);
68
69static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
70{
71 struct cpufreq_stats *stats = policy->stats;
72 bool pending = READ_ONCE(stats->reset_pending);
73 unsigned long long time;
74 ssize_t len = 0;
75 int i;
76
77 for (i = 0; i < stats->state_num; i++) {
78 if (pending) {
79 if (i == stats->last_index) {
80 /*
81 * Prevent the reset_time read from occurring
82 * before the reset_pending read above.
83 */
84 smp_rmb();
85 time = local_clock() - READ_ONCE(stats->reset_time);
86 } else {
87 time = 0;
88 }
89 } else {
90 time = stats->time_in_state[i];
91 if (i == stats->last_index)
92 time += local_clock() - stats->last_time;
93 }
94
95 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
96 nsec_to_clock_t(time));
97 }
98 return len;
99}
100cpufreq_freq_attr_ro(time_in_state);
101
102/* We don't care what is written to the attribute */
103static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
104 size_t count)
105{
106 struct cpufreq_stats *stats = policy->stats;
107
108 /*
109 * Defer resetting of stats to cpufreq_stats_record_transition() to
110 * avoid races.
111 */
112 WRITE_ONCE(stats->reset_time, local_clock());
113 /*
114 * The memory barrier below is to prevent the readers of reset_time from
115 * seeing a stale or partially updated value.
116 */
117 smp_wmb();
118 WRITE_ONCE(stats->reset_pending, 1);
119
120 return count;
121}
122cpufreq_freq_attr_wo(reset);
123
124static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
125{
126 struct cpufreq_stats *stats = policy->stats;
127 bool pending = READ_ONCE(stats->reset_pending);
128 ssize_t len = 0;
129 int i, j, count;
130
131 len += sysfs_emit_at(buf, len, " From : To\n");
132 len += sysfs_emit_at(buf, len, " : ");
133 for (i = 0; i < stats->state_num; i++) {
134 if (len >= PAGE_SIZE - 1)
135 break;
136 len += sysfs_emit_at(buf, len, "%9u ", stats->freq_table[i]);
137 }
138 if (len >= PAGE_SIZE - 1)
139 return PAGE_SIZE - 1;
140
141 len += sysfs_emit_at(buf, len, "\n");
142
143 for (i = 0; i < stats->state_num; i++) {
144 if (len >= PAGE_SIZE - 1)
145 break;
146
147 len += sysfs_emit_at(buf, len, "%9u: ", stats->freq_table[i]);
148
149 for (j = 0; j < stats->state_num; j++) {
150 if (len >= PAGE_SIZE - 1)
151 break;
152
153 if (pending)
154 count = 0;
155 else
156 count = stats->trans_table[i * stats->max_state + j];
157
158 len += sysfs_emit_at(buf, len, "%9u ", count);
159 }
160 if (len >= PAGE_SIZE - 1)
161 break;
162 len += sysfs_emit_at(buf, len, "\n");
163 }
164
165 if (len >= PAGE_SIZE - 1) {
166 pr_warn_once("cpufreq transition table exceeds PAGE_SIZE. Disabling\n");
167 return -EFBIG;
168 }
169 return len;
170}
171cpufreq_freq_attr_ro(trans_table);
172
173static struct attribute *default_attrs[] = {
174 &total_trans.attr,
175 &time_in_state.attr,
176 &reset.attr,
177 &trans_table.attr,
178 NULL
179};
180static const struct attribute_group stats_attr_group = {
181 .attrs = default_attrs,
182 .name = "stats"
183};
184
185static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
186{
187 int index;
188 for (index = 0; index < stats->max_state; index++)
189 if (stats->freq_table[index] == freq)
190 return index;
191 return -1;
192}
193
194void cpufreq_stats_free_table(struct cpufreq_policy *policy)
195{
196 struct cpufreq_stats *stats = policy->stats;
197
198 /* Already freed */
199 if (!stats)
200 return;
201
202 pr_debug("%s: Free stats table\n", __func__);
203
204 sysfs_remove_group(&policy->kobj, &stats_attr_group);
205 kfree(stats->time_in_state);
206 kfree(stats);
207 policy->stats = NULL;
208}
209
210void cpufreq_stats_create_table(struct cpufreq_policy *policy)
211{
212 unsigned int i = 0, count;
213 struct cpufreq_stats *stats;
214 unsigned int alloc_size;
215 struct cpufreq_frequency_table *pos;
216
217 count = cpufreq_table_count_valid_entries(policy);
218 if (!count)
219 return;
220
221 /* stats already initialized */
222 if (policy->stats)
223 return;
224
225 stats = kzalloc(sizeof(*stats), GFP_KERNEL);
226 if (!stats)
227 return;
228
229 alloc_size = count * sizeof(int) + count * sizeof(u64);
230
231 alloc_size += count * count * sizeof(int);
232
233 /* Allocate memory for time_in_state/freq_table/trans_table in one go */
234 stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
235 if (!stats->time_in_state)
236 goto free_stat;
237
238 stats->freq_table = (unsigned int *)(stats->time_in_state + count);
239
240 stats->trans_table = stats->freq_table + count;
241
242 stats->max_state = count;
243
244 /* Find valid-unique entries */
245 cpufreq_for_each_valid_entry(pos, policy->freq_table)
246 if (policy->freq_table_sorted != CPUFREQ_TABLE_UNSORTED ||
247 freq_table_get_index(stats, pos->frequency) == -1)
248 stats->freq_table[i++] = pos->frequency;
249
250 stats->state_num = i;
251 stats->last_time = local_clock();
252 stats->last_index = freq_table_get_index(stats, policy->cur);
253
254 policy->stats = stats;
255 if (!sysfs_create_group(&policy->kobj, &stats_attr_group))
256 return;
257
258 /* We failed, release resources */
259 policy->stats = NULL;
260 kfree(stats->time_in_state);
261free_stat:
262 kfree(stats);
263}
264
265void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
266 unsigned int new_freq)
267{
268 struct cpufreq_stats *stats = policy->stats;
269 int old_index, new_index;
270
271 if (unlikely(!stats))
272 return;
273
274 if (unlikely(READ_ONCE(stats->reset_pending)))
275 cpufreq_stats_reset_table(stats);
276
277 old_index = stats->last_index;
278 new_index = freq_table_get_index(stats, new_freq);
279
280 /* We can't do stats->time_in_state[-1]= .. */
281 if (unlikely(old_index == -1 || new_index == -1 || old_index == new_index))
282 return;
283
284 cpufreq_stats_update(stats, stats->last_time);
285
286 stats->last_index = new_index;
287 stats->trans_table[old_index * stats->max_state + new_index]++;
288 stats->total_trans++;
289}