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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}
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 total_trans;
22 unsigned long long last_time;
23 unsigned int max_state;
24 unsigned int state_num;
25 unsigned int last_index;
26 u64 *time_in_state;
27 unsigned int *freq_table;
28#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
29 unsigned int *trans_table;
30#endif
31};
32
33static int cpufreq_stats_update(struct cpufreq_stats *stats)
34{
35 unsigned long long cur_time = get_jiffies_64();
36
37 spin_lock(&cpufreq_stats_lock);
38 stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
39 stats->last_time = cur_time;
40 spin_unlock(&cpufreq_stats_lock);
41 return 0;
42}
43
44static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
45{
46 return sprintf(buf, "%d\n", policy->stats->total_trans);
47}
48
49static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
50{
51 struct cpufreq_stats *stats = policy->stats;
52 ssize_t len = 0;
53 int i;
54
55 cpufreq_stats_update(stats);
56 for (i = 0; i < stats->state_num; i++) {
57 len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
58 (unsigned long long)
59 jiffies_64_to_clock_t(stats->time_in_state[i]));
60 }
61 return len;
62}
63
64#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
65static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
66{
67 struct cpufreq_stats *stats = policy->stats;
68 ssize_t len = 0;
69 int i, j;
70
71 len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
72 len += snprintf(buf + len, PAGE_SIZE - len, " : ");
73 for (i = 0; i < stats->state_num; i++) {
74 if (len >= PAGE_SIZE)
75 break;
76 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
77 stats->freq_table[i]);
78 }
79 if (len >= PAGE_SIZE)
80 return PAGE_SIZE;
81
82 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
83
84 for (i = 0; i < stats->state_num; i++) {
85 if (len >= PAGE_SIZE)
86 break;
87
88 len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
89 stats->freq_table[i]);
90
91 for (j = 0; j < stats->state_num; j++) {
92 if (len >= PAGE_SIZE)
93 break;
94 len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
95 stats->trans_table[i*stats->max_state+j]);
96 }
97 if (len >= PAGE_SIZE)
98 break;
99 len += snprintf(buf + len, PAGE_SIZE - len, "\n");
100 }
101 if (len >= PAGE_SIZE)
102 return PAGE_SIZE;
103 return len;
104}
105cpufreq_freq_attr_ro(trans_table);
106#endif
107
108cpufreq_freq_attr_ro(total_trans);
109cpufreq_freq_attr_ro(time_in_state);
110
111static struct attribute *default_attrs[] = {
112 &total_trans.attr,
113 &time_in_state.attr,
114#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
115 &trans_table.attr,
116#endif
117 NULL
118};
119static struct attribute_group stats_attr_group = {
120 .attrs = default_attrs,
121 .name = "stats"
122};
123
124static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
125{
126 int index;
127 for (index = 0; index < stats->max_state; index++)
128 if (stats->freq_table[index] == freq)
129 return index;
130 return -1;
131}
132
133static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
134{
135 struct cpufreq_stats *stats = policy->stats;
136
137 /* Already freed */
138 if (!stats)
139 return;
140
141 pr_debug("%s: Free stats table\n", __func__);
142
143 sysfs_remove_group(&policy->kobj, &stats_attr_group);
144 kfree(stats->time_in_state);
145 kfree(stats);
146 policy->stats = NULL;
147}
148
149static void cpufreq_stats_free_table(unsigned int cpu)
150{
151 struct cpufreq_policy *policy;
152
153 policy = cpufreq_cpu_get(cpu);
154 if (!policy)
155 return;
156
157 __cpufreq_stats_free_table(policy);
158
159 cpufreq_cpu_put(policy);
160}
161
162static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
163{
164 unsigned int i = 0, count = 0, ret = -ENOMEM;
165 struct cpufreq_stats *stats;
166 unsigned int alloc_size;
167 unsigned int cpu = policy->cpu;
168 struct cpufreq_frequency_table *pos, *table;
169
170 /* We need cpufreq table for creating stats table */
171 table = cpufreq_frequency_get_table(cpu);
172 if (unlikely(!table))
173 return 0;
174
175 /* stats already initialized */
176 if (policy->stats)
177 return -EEXIST;
178
179 stats = kzalloc(sizeof(*stats), GFP_KERNEL);
180 if (!stats)
181 return -ENOMEM;
182
183 /* Find total allocation size */
184 cpufreq_for_each_valid_entry(pos, table)
185 count++;
186
187 alloc_size = count * sizeof(int) + count * sizeof(u64);
188
189#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
190 alloc_size += count * count * sizeof(int);
191#endif
192
193 /* Allocate memory for time_in_state/freq_table/trans_table in one go */
194 stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
195 if (!stats->time_in_state)
196 goto free_stat;
197
198 stats->freq_table = (unsigned int *)(stats->time_in_state + count);
199
200#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
201 stats->trans_table = stats->freq_table + count;
202#endif
203
204 stats->max_state = count;
205
206 /* Find valid-unique entries */
207 cpufreq_for_each_valid_entry(pos, table)
208 if (freq_table_get_index(stats, pos->frequency) == -1)
209 stats->freq_table[i++] = pos->frequency;
210
211 stats->state_num = i;
212 stats->last_time = get_jiffies_64();
213 stats->last_index = freq_table_get_index(stats, policy->cur);
214
215 policy->stats = stats;
216 ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
217 if (!ret)
218 return 0;
219
220 /* We failed, release resources */
221 policy->stats = NULL;
222 kfree(stats->time_in_state);
223free_stat:
224 kfree(stats);
225
226 return ret;
227}
228
229static void cpufreq_stats_create_table(unsigned int cpu)
230{
231 struct cpufreq_policy *policy;
232
233 /*
234 * "likely(!policy)" because normally cpufreq_stats will be registered
235 * before cpufreq driver
236 */
237 policy = cpufreq_cpu_get(cpu);
238 if (likely(!policy))
239 return;
240
241 __cpufreq_stats_create_table(policy);
242
243 cpufreq_cpu_put(policy);
244}
245
246static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
247 unsigned long val, void *data)
248{
249 int ret = 0;
250 struct cpufreq_policy *policy = data;
251
252 if (val == CPUFREQ_CREATE_POLICY)
253 ret = __cpufreq_stats_create_table(policy);
254 else if (val == CPUFREQ_REMOVE_POLICY)
255 __cpufreq_stats_free_table(policy);
256
257 return ret;
258}
259
260static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
261 unsigned long val, void *data)
262{
263 struct cpufreq_freqs *freq = data;
264 struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
265 struct cpufreq_stats *stats;
266 int old_index, new_index;
267
268 if (!policy) {
269 pr_err("%s: No policy found\n", __func__);
270 return 0;
271 }
272
273 if (val != CPUFREQ_POSTCHANGE)
274 goto put_policy;
275
276 if (!policy->stats) {
277 pr_debug("%s: No stats found\n", __func__);
278 goto put_policy;
279 }
280
281 stats = policy->stats;
282
283 old_index = stats->last_index;
284 new_index = freq_table_get_index(stats, freq->new);
285
286 /* We can't do stats->time_in_state[-1]= .. */
287 if (old_index == -1 || new_index == -1)
288 goto put_policy;
289
290 if (old_index == new_index)
291 goto put_policy;
292
293 cpufreq_stats_update(stats);
294
295 stats->last_index = new_index;
296#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
297 stats->trans_table[old_index * stats->max_state + new_index]++;
298#endif
299 stats->total_trans++;
300
301put_policy:
302 cpufreq_cpu_put(policy);
303 return 0;
304}
305
306static struct notifier_block notifier_policy_block = {
307 .notifier_call = cpufreq_stat_notifier_policy
308};
309
310static struct notifier_block notifier_trans_block = {
311 .notifier_call = cpufreq_stat_notifier_trans
312};
313
314static int __init cpufreq_stats_init(void)
315{
316 int ret;
317 unsigned int cpu;
318
319 spin_lock_init(&cpufreq_stats_lock);
320 ret = cpufreq_register_notifier(¬ifier_policy_block,
321 CPUFREQ_POLICY_NOTIFIER);
322 if (ret)
323 return ret;
324
325 for_each_online_cpu(cpu)
326 cpufreq_stats_create_table(cpu);
327
328 ret = cpufreq_register_notifier(¬ifier_trans_block,
329 CPUFREQ_TRANSITION_NOTIFIER);
330 if (ret) {
331 cpufreq_unregister_notifier(¬ifier_policy_block,
332 CPUFREQ_POLICY_NOTIFIER);
333 for_each_online_cpu(cpu)
334 cpufreq_stats_free_table(cpu);
335 return ret;
336 }
337
338 return 0;
339}
340static void __exit cpufreq_stats_exit(void)
341{
342 unsigned int cpu;
343
344 cpufreq_unregister_notifier(¬ifier_policy_block,
345 CPUFREQ_POLICY_NOTIFIER);
346 cpufreq_unregister_notifier(¬ifier_trans_block,
347 CPUFREQ_TRANSITION_NOTIFIER);
348 for_each_online_cpu(cpu)
349 cpufreq_stats_free_table(cpu);
350}
351
352MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
353MODULE_DESCRIPTION("Export cpufreq stats via sysfs");
354MODULE_LICENSE("GPL");
355
356module_init(cpufreq_stats_init);
357module_exit(cpufreq_stats_exit);