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-rw-r--r--kernel/trace/ring_buffer_benchmark.c416
1 files changed, 416 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
new file mode 100644
index 000000000000..8d68e149a8b3
--- /dev/null
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -0,0 +1,416 @@
1/*
2 * ring buffer tester and benchmark
3 *
4 * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
5 */
6#include <linux/ring_buffer.h>
7#include <linux/completion.h>
8#include <linux/kthread.h>
9#include <linux/module.h>
10#include <linux/time.h>
11
12struct rb_page {
13 u64 ts;
14 local_t commit;
15 char data[4080];
16};
17
18/* run time and sleep time in seconds */
19#define RUN_TIME 10
20#define SLEEP_TIME 10
21
22/* number of events for writer to wake up the reader */
23static int wakeup_interval = 100;
24
25static int reader_finish;
26static struct completion read_start;
27static struct completion read_done;
28
29static struct ring_buffer *buffer;
30static struct task_struct *producer;
31static struct task_struct *consumer;
32static unsigned long read;
33
34static int disable_reader;
35module_param(disable_reader, uint, 0644);
36MODULE_PARM_DESC(disable_reader, "only run producer");
37
38static int read_events;
39
40static int kill_test;
41
42#define KILL_TEST() \
43 do { \
44 if (!kill_test) { \
45 kill_test = 1; \
46 WARN_ON(1); \
47 } \
48 } while (0)
49
50enum event_status {
51 EVENT_FOUND,
52 EVENT_DROPPED,
53};
54
55static enum event_status read_event(int cpu)
56{
57 struct ring_buffer_event *event;
58 int *entry;
59 u64 ts;
60
61 event = ring_buffer_consume(buffer, cpu, &ts);
62 if (!event)
63 return EVENT_DROPPED;
64
65 entry = ring_buffer_event_data(event);
66 if (*entry != cpu) {
67 KILL_TEST();
68 return EVENT_DROPPED;
69 }
70
71 read++;
72 return EVENT_FOUND;
73}
74
75static enum event_status read_page(int cpu)
76{
77 struct ring_buffer_event *event;
78 struct rb_page *rpage;
79 unsigned long commit;
80 void *bpage;
81 int *entry;
82 int ret;
83 int inc;
84 int i;
85
86 bpage = ring_buffer_alloc_read_page(buffer);
87 if (!bpage)
88 return EVENT_DROPPED;
89
90 ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
91 if (ret >= 0) {
92 rpage = bpage;
93 commit = local_read(&rpage->commit);
94 for (i = 0; i < commit && !kill_test; i += inc) {
95
96 if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
97 KILL_TEST();
98 break;
99 }
100
101 inc = -1;
102 event = (void *)&rpage->data[i];
103 switch (event->type_len) {
104 case RINGBUF_TYPE_PADDING:
105 /* We don't expect any padding */
106 KILL_TEST();
107 break;
108 case RINGBUF_TYPE_TIME_EXTEND:
109 inc = 8;
110 break;
111 case 0:
112 entry = ring_buffer_event_data(event);
113 if (*entry != cpu) {
114 KILL_TEST();
115 break;
116 }
117 read++;
118 if (!event->array[0]) {
119 KILL_TEST();
120 break;
121 }
122 inc = event->array[0];
123 break;
124 default:
125 entry = ring_buffer_event_data(event);
126 if (*entry != cpu) {
127 KILL_TEST();
128 break;
129 }
130 read++;
131 inc = ((event->type_len + 1) * 4);
132 }
133 if (kill_test)
134 break;
135
136 if (inc <= 0) {
137 KILL_TEST();
138 break;
139 }
140 }
141 }
142 ring_buffer_free_read_page(buffer, bpage);
143
144 if (ret < 0)
145 return EVENT_DROPPED;
146 return EVENT_FOUND;
147}
148
149static void ring_buffer_consumer(void)
150{
151 /* toggle between reading pages and events */
152 read_events ^= 1;
153
154 read = 0;
155 while (!reader_finish && !kill_test) {
156 int found;
157
158 do {
159 int cpu;
160
161 found = 0;
162 for_each_online_cpu(cpu) {
163 enum event_status stat;
164
165 if (read_events)
166 stat = read_event(cpu);
167 else
168 stat = read_page(cpu);
169
170 if (kill_test)
171 break;
172 if (stat == EVENT_FOUND)
173 found = 1;
174 }
175 } while (found && !kill_test);
176
177 set_current_state(TASK_INTERRUPTIBLE);
178 if (reader_finish)
179 break;
180
181 schedule();
182 __set_current_state(TASK_RUNNING);
183 }
184 reader_finish = 0;
185 complete(&read_done);
186}
187
188static void ring_buffer_producer(void)
189{
190 struct timeval start_tv;
191 struct timeval end_tv;
192 unsigned long long time;
193 unsigned long long entries;
194 unsigned long long overruns;
195 unsigned long missed = 0;
196 unsigned long hit = 0;
197 unsigned long avg;
198 int cnt = 0;
199
200 /*
201 * Hammer the buffer for 10 secs (this may
202 * make the system stall)
203 */
204 pr_info("Starting ring buffer hammer\n");
205 do_gettimeofday(&start_tv);
206 do {
207 struct ring_buffer_event *event;
208 int *entry;
209
210 event = ring_buffer_lock_reserve(buffer, 10);
211 if (!event) {
212 missed++;
213 } else {
214 hit++;
215 entry = ring_buffer_event_data(event);
216 *entry = smp_processor_id();
217 ring_buffer_unlock_commit(buffer, event);
218 }
219 do_gettimeofday(&end_tv);
220
221 cnt++;
222 if (consumer && !(cnt % wakeup_interval))
223 wake_up_process(consumer);
224
225#ifndef CONFIG_PREEMPT
226 /*
227 * If we are a non preempt kernel, the 10 second run will
228 * stop everything while it runs. Instead, we will call
229 * cond_resched and also add any time that was lost by a
230 * rescedule.
231 *
232 * Do a cond resched at the same frequency we would wake up
233 * the reader.
234 */
235 if (cnt % wakeup_interval)
236 cond_resched();
237#endif
238
239 } while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
240 pr_info("End ring buffer hammer\n");
241
242 if (consumer) {
243 /* Init both completions here to avoid races */
244 init_completion(&read_start);
245 init_completion(&read_done);
246 /* the completions must be visible before the finish var */
247 smp_wmb();
248 reader_finish = 1;
249 /* finish var visible before waking up the consumer */
250 smp_wmb();
251 wake_up_process(consumer);
252 wait_for_completion(&read_done);
253 }
254
255 time = end_tv.tv_sec - start_tv.tv_sec;
256 time *= USEC_PER_SEC;
257 time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
258
259 entries = ring_buffer_entries(buffer);
260 overruns = ring_buffer_overruns(buffer);
261
262 if (kill_test)
263 pr_info("ERROR!\n");
264 pr_info("Time: %lld (usecs)\n", time);
265 pr_info("Overruns: %lld\n", overruns);
266 if (disable_reader)
267 pr_info("Read: (reader disabled)\n");
268 else
269 pr_info("Read: %ld (by %s)\n", read,
270 read_events ? "events" : "pages");
271 pr_info("Entries: %lld\n", entries);
272 pr_info("Total: %lld\n", entries + overruns + read);
273 pr_info("Missed: %ld\n", missed);
274 pr_info("Hit: %ld\n", hit);
275
276 /* Convert time from usecs to millisecs */
277 do_div(time, USEC_PER_MSEC);
278 if (time)
279 hit /= (long)time;
280 else
281 pr_info("TIME IS ZERO??\n");
282
283 pr_info("Entries per millisec: %ld\n", hit);
284
285 if (hit) {
286 /* Calculate the average time in nanosecs */
287 avg = NSEC_PER_MSEC / hit;
288 pr_info("%ld ns per entry\n", avg);
289 }
290
291 if (missed) {
292 if (time)
293 missed /= (long)time;
294
295 pr_info("Total iterations per millisec: %ld\n", hit + missed);
296
297 /* it is possible that hit + missed will overflow and be zero */
298 if (!(hit + missed)) {
299 pr_info("hit + missed overflowed and totalled zero!\n");
300 hit--; /* make it non zero */
301 }
302
303 /* Caculate the average time in nanosecs */
304 avg = NSEC_PER_MSEC / (hit + missed);
305 pr_info("%ld ns per entry\n", avg);
306 }
307}
308
309static void wait_to_die(void)
310{
311 set_current_state(TASK_INTERRUPTIBLE);
312 while (!kthread_should_stop()) {
313 schedule();
314 set_current_state(TASK_INTERRUPTIBLE);
315 }
316 __set_current_state(TASK_RUNNING);
317}
318
319static int ring_buffer_consumer_thread(void *arg)
320{
321 while (!kthread_should_stop() && !kill_test) {
322 complete(&read_start);
323
324 ring_buffer_consumer();
325
326 set_current_state(TASK_INTERRUPTIBLE);
327 if (kthread_should_stop() || kill_test)
328 break;
329
330 schedule();
331 __set_current_state(TASK_RUNNING);
332 }
333 __set_current_state(TASK_RUNNING);
334
335 if (kill_test)
336 wait_to_die();
337
338 return 0;
339}
340
341static int ring_buffer_producer_thread(void *arg)
342{
343 init_completion(&read_start);
344
345 while (!kthread_should_stop() && !kill_test) {
346 ring_buffer_reset(buffer);
347
348 if (consumer) {
349 smp_wmb();
350 wake_up_process(consumer);
351 wait_for_completion(&read_start);
352 }
353
354 ring_buffer_producer();
355
356 pr_info("Sleeping for 10 secs\n");
357 set_current_state(TASK_INTERRUPTIBLE);
358 schedule_timeout(HZ * SLEEP_TIME);
359 __set_current_state(TASK_RUNNING);
360 }
361
362 if (kill_test)
363 wait_to_die();
364
365 return 0;
366}
367
368static int __init ring_buffer_benchmark_init(void)
369{
370 int ret;
371
372 /* make a one meg buffer in overwite mode */
373 buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
374 if (!buffer)
375 return -ENOMEM;
376
377 if (!disable_reader) {
378 consumer = kthread_create(ring_buffer_consumer_thread,
379 NULL, "rb_consumer");
380 ret = PTR_ERR(consumer);
381 if (IS_ERR(consumer))
382 goto out_fail;
383 }
384
385 producer = kthread_run(ring_buffer_producer_thread,
386 NULL, "rb_producer");
387 ret = PTR_ERR(producer);
388
389 if (IS_ERR(producer))
390 goto out_kill;
391
392 return 0;
393
394 out_kill:
395 if (consumer)
396 kthread_stop(consumer);
397
398 out_fail:
399 ring_buffer_free(buffer);
400 return ret;
401}
402
403static void __exit ring_buffer_benchmark_exit(void)
404{
405 kthread_stop(producer);
406 if (consumer)
407 kthread_stop(consumer);
408 ring_buffer_free(buffer);
409}
410
411module_init(ring_buffer_benchmark_init);
412module_exit(ring_buffer_benchmark_exit);
413
414MODULE_AUTHOR("Steven Rostedt");
415MODULE_DESCRIPTION("ring_buffer_benchmark");
416MODULE_LICENSE("GPL");
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-22 23:22:57 -0500