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Commit | Line | Data |
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5092dbc9 SR |
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> | |
ae7e81c0 | 9 | #include <uapi/linux/sched/types.h> |
5092dbc9 | 10 | #include <linux/module.h> |
da194930 | 11 | #include <linux/ktime.h> |
79615760 | 12 | #include <asm/local.h> |
5092dbc9 SR |
13 | |
14 | struct rb_page { | |
15 | u64 ts; | |
16 | local_t commit; | |
17 | char data[4080]; | |
18 | }; | |
19 | ||
20 | /* run time and sleep time in seconds */ | |
da194930 | 21 | #define RUN_TIME 10ULL |
5092dbc9 SR |
22 | #define SLEEP_TIME 10 |
23 | ||
24 | /* number of events for writer to wake up the reader */ | |
25 | static int wakeup_interval = 100; | |
26 | ||
27 | static int reader_finish; | |
8b46ff69 PM |
28 | static DECLARE_COMPLETION(read_start); |
29 | static DECLARE_COMPLETION(read_done); | |
5092dbc9 SR |
30 | |
31 | static struct ring_buffer *buffer; | |
32 | static struct task_struct *producer; | |
33 | static struct task_struct *consumer; | |
34 | static unsigned long read; | |
35 | ||
33d657d1 | 36 | static unsigned int disable_reader; |
5092dbc9 SR |
37 | module_param(disable_reader, uint, 0644); |
38 | MODULE_PARM_DESC(disable_reader, "only run producer"); | |
39 | ||
33d657d1 | 40 | static unsigned int write_iteration = 50; |
a6f0eb6a SR |
41 | module_param(write_iteration, uint, 0644); |
42 | MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings"); | |
43 | ||
2b3942e4 DY |
44 | static int producer_nice = MAX_NICE; |
45 | static int consumer_nice = MAX_NICE; | |
7ac07434 SR |
46 | |
47 | static int producer_fifo = -1; | |
48 | static int consumer_fifo = -1; | |
49 | ||
7364e865 | 50 | module_param(producer_nice, int, 0644); |
7ac07434 SR |
51 | MODULE_PARM_DESC(producer_nice, "nice prio for producer"); |
52 | ||
7364e865 | 53 | module_param(consumer_nice, int, 0644); |
7ac07434 SR |
54 | MODULE_PARM_DESC(consumer_nice, "nice prio for consumer"); |
55 | ||
7364e865 | 56 | module_param(producer_fifo, int, 0644); |
7ac07434 SR |
57 | MODULE_PARM_DESC(producer_fifo, "fifo prio for producer"); |
58 | ||
7364e865 | 59 | module_param(consumer_fifo, int, 0644); |
7ac07434 SR |
60 | MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer"); |
61 | ||
5092dbc9 SR |
62 | static int read_events; |
63 | ||
f47cb66d | 64 | static int test_error; |
5092dbc9 | 65 | |
f47cb66d | 66 | #define TEST_ERROR() \ |
5092dbc9 | 67 | do { \ |
f47cb66d PM |
68 | if (!test_error) { \ |
69 | test_error = 1; \ | |
5092dbc9 SR |
70 | WARN_ON(1); \ |
71 | } \ | |
72 | } while (0) | |
73 | ||
74 | enum event_status { | |
75 | EVENT_FOUND, | |
76 | EVENT_DROPPED, | |
77 | }; | |
78 | ||
f47cb66d PM |
79 | static bool break_test(void) |
80 | { | |
81 | return test_error || kthread_should_stop(); | |
82 | } | |
83 | ||
5092dbc9 SR |
84 | static enum event_status read_event(int cpu) |
85 | { | |
86 | struct ring_buffer_event *event; | |
87 | int *entry; | |
88 | u64 ts; | |
89 | ||
66a8cb95 | 90 | event = ring_buffer_consume(buffer, cpu, &ts, NULL); |
5092dbc9 SR |
91 | if (!event) |
92 | return EVENT_DROPPED; | |
93 | ||
94 | entry = ring_buffer_event_data(event); | |
95 | if (*entry != cpu) { | |
f47cb66d | 96 | TEST_ERROR(); |
5092dbc9 SR |
97 | return EVENT_DROPPED; |
98 | } | |
99 | ||
100 | read++; | |
101 | return EVENT_FOUND; | |
102 | } | |
103 | ||
104 | static enum event_status read_page(int cpu) | |
105 | { | |
106 | struct ring_buffer_event *event; | |
107 | struct rb_page *rpage; | |
108 | unsigned long commit; | |
109 | void *bpage; | |
110 | int *entry; | |
111 | int ret; | |
112 | int inc; | |
113 | int i; | |
114 | ||
7ea59064 | 115 | bpage = ring_buffer_alloc_read_page(buffer, cpu); |
a7e52ad7 | 116 | if (IS_ERR(bpage)) |
00c81a58 SR |
117 | return EVENT_DROPPED; |
118 | ||
5092dbc9 SR |
119 | ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1); |
120 | if (ret >= 0) { | |
121 | rpage = bpage; | |
a838b2e6 SR |
122 | /* The commit may have missed event flags set, clear them */ |
123 | commit = local_read(&rpage->commit) & 0xfffff; | |
f47cb66d | 124 | for (i = 0; i < commit && !test_error ; i += inc) { |
5092dbc9 SR |
125 | |
126 | if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) { | |
f47cb66d | 127 | TEST_ERROR(); |
5092dbc9 SR |
128 | break; |
129 | } | |
130 | ||
131 | inc = -1; | |
132 | event = (void *)&rpage->data[i]; | |
133 | switch (event->type_len) { | |
134 | case RINGBUF_TYPE_PADDING: | |
9086c7b9 SR |
135 | /* failed writes may be discarded events */ |
136 | if (!event->time_delta) | |
f47cb66d | 137 | TEST_ERROR(); |
9086c7b9 | 138 | inc = event->array[0] + 4; |
5092dbc9 SR |
139 | break; |
140 | case RINGBUF_TYPE_TIME_EXTEND: | |
141 | inc = 8; | |
142 | break; | |
143 | case 0: | |
144 | entry = ring_buffer_event_data(event); | |
145 | if (*entry != cpu) { | |
f47cb66d | 146 | TEST_ERROR(); |
5092dbc9 SR |
147 | break; |
148 | } | |
149 | read++; | |
150 | if (!event->array[0]) { | |
f47cb66d | 151 | TEST_ERROR(); |
5092dbc9 SR |
152 | break; |
153 | } | |
9086c7b9 | 154 | inc = event->array[0] + 4; |
5092dbc9 SR |
155 | break; |
156 | default: | |
157 | entry = ring_buffer_event_data(event); | |
158 | if (*entry != cpu) { | |
f47cb66d | 159 | TEST_ERROR(); |
5092dbc9 SR |
160 | break; |
161 | } | |
162 | read++; | |
163 | inc = ((event->type_len + 1) * 4); | |
164 | } | |
f47cb66d | 165 | if (test_error) |
5092dbc9 SR |
166 | break; |
167 | ||
168 | if (inc <= 0) { | |
f47cb66d | 169 | TEST_ERROR(); |
5092dbc9 SR |
170 | break; |
171 | } | |
172 | } | |
173 | } | |
73a757e6 | 174 | ring_buffer_free_read_page(buffer, cpu, bpage); |
5092dbc9 SR |
175 | |
176 | if (ret < 0) | |
177 | return EVENT_DROPPED; | |
178 | return EVENT_FOUND; | |
179 | } | |
180 | ||
181 | static void ring_buffer_consumer(void) | |
182 | { | |
183 | /* toggle between reading pages and events */ | |
184 | read_events ^= 1; | |
185 | ||
186 | read = 0; | |
8b46ff69 PM |
187 | /* |
188 | * Continue running until the producer specifically asks to stop | |
189 | * and is ready for the completion. | |
190 | */ | |
191 | while (!READ_ONCE(reader_finish)) { | |
192 | int found = 1; | |
5092dbc9 | 193 | |
f47cb66d | 194 | while (found && !test_error) { |
5092dbc9 SR |
195 | int cpu; |
196 | ||
197 | found = 0; | |
198 | for_each_online_cpu(cpu) { | |
199 | enum event_status stat; | |
200 | ||
201 | if (read_events) | |
202 | stat = read_event(cpu); | |
203 | else | |
204 | stat = read_page(cpu); | |
205 | ||
f47cb66d | 206 | if (test_error) |
5092dbc9 | 207 | break; |
8b46ff69 | 208 | |
5092dbc9 SR |
209 | if (stat == EVENT_FOUND) |
210 | found = 1; | |
8b46ff69 | 211 | |
5092dbc9 | 212 | } |
8b46ff69 | 213 | } |
5092dbc9 | 214 | |
8b46ff69 PM |
215 | /* Wait till the producer wakes us up when there is more data |
216 | * available or when the producer wants us to finish reading. | |
217 | */ | |
5092dbc9 SR |
218 | set_current_state(TASK_INTERRUPTIBLE); |
219 | if (reader_finish) | |
220 | break; | |
221 | ||
222 | schedule(); | |
5092dbc9 | 223 | } |
8b46ff69 | 224 | __set_current_state(TASK_RUNNING); |
5092dbc9 SR |
225 | reader_finish = 0; |
226 | complete(&read_done); | |
227 | } | |
228 | ||
229 | static void ring_buffer_producer(void) | |
230 | { | |
da194930 | 231 | ktime_t start_time, end_time, timeout; |
5092dbc9 SR |
232 | unsigned long long time; |
233 | unsigned long long entries; | |
234 | unsigned long long overruns; | |
235 | unsigned long missed = 0; | |
236 | unsigned long hit = 0; | |
237 | unsigned long avg; | |
238 | int cnt = 0; | |
239 | ||
240 | /* | |
241 | * Hammer the buffer for 10 secs (this may | |
242 | * make the system stall) | |
243 | */ | |
4b221f03 | 244 | trace_printk("Starting ring buffer hammer\n"); |
da194930 TR |
245 | start_time = ktime_get(); |
246 | timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC); | |
5092dbc9 SR |
247 | do { |
248 | struct ring_buffer_event *event; | |
249 | int *entry; | |
a6f0eb6a SR |
250 | int i; |
251 | ||
252 | for (i = 0; i < write_iteration; i++) { | |
253 | event = ring_buffer_lock_reserve(buffer, 10); | |
254 | if (!event) { | |
255 | missed++; | |
256 | } else { | |
257 | hit++; | |
258 | entry = ring_buffer_event_data(event); | |
259 | *entry = smp_processor_id(); | |
260 | ring_buffer_unlock_commit(buffer, event); | |
261 | } | |
5092dbc9 | 262 | } |
da194930 | 263 | end_time = ktime_get(); |
5092dbc9 | 264 | |
0574ea42 SR |
265 | cnt++; |
266 | if (consumer && !(cnt % wakeup_interval)) | |
5092dbc9 SR |
267 | wake_up_process(consumer); |
268 | ||
0574ea42 | 269 | #ifndef CONFIG_PREEMPT |
29c8000e SR |
270 | /* |
271 | * If we are a non preempt kernel, the 10 second run will | |
272 | * stop everything while it runs. Instead, we will call | |
273 | * cond_resched and also add any time that was lost by a | |
274 | * rescedule. | |
0574ea42 SR |
275 | * |
276 | * Do a cond resched at the same frequency we would wake up | |
277 | * the reader. | |
29c8000e | 278 | */ |
0574ea42 SR |
279 | if (cnt % wakeup_interval) |
280 | cond_resched(); | |
281 | #endif | |
f47cb66d | 282 | } while (ktime_before(end_time, timeout) && !break_test()); |
4b221f03 | 283 | trace_printk("End ring buffer hammer\n"); |
5092dbc9 SR |
284 | |
285 | if (consumer) { | |
286 | /* Init both completions here to avoid races */ | |
287 | init_completion(&read_start); | |
288 | init_completion(&read_done); | |
289 | /* the completions must be visible before the finish var */ | |
290 | smp_wmb(); | |
291 | reader_finish = 1; | |
5092dbc9 SR |
292 | wake_up_process(consumer); |
293 | wait_for_completion(&read_done); | |
294 | } | |
295 | ||
da194930 | 296 | time = ktime_us_delta(end_time, start_time); |
5092dbc9 SR |
297 | |
298 | entries = ring_buffer_entries(buffer); | |
299 | overruns = ring_buffer_overruns(buffer); | |
300 | ||
f47cb66d | 301 | if (test_error) |
4b221f03 | 302 | trace_printk("ERROR!\n"); |
7ac07434 SR |
303 | |
304 | if (!disable_reader) { | |
305 | if (consumer_fifo < 0) | |
306 | trace_printk("Running Consumer at nice: %d\n", | |
307 | consumer_nice); | |
308 | else | |
309 | trace_printk("Running Consumer at SCHED_FIFO %d\n", | |
310 | consumer_fifo); | |
311 | } | |
312 | if (producer_fifo < 0) | |
313 | trace_printk("Running Producer at nice: %d\n", | |
314 | producer_nice); | |
315 | else | |
316 | trace_printk("Running Producer at SCHED_FIFO %d\n", | |
317 | producer_fifo); | |
318 | ||
319 | /* Let the user know that the test is running at low priority */ | |
320 | if (producer_fifo < 0 && consumer_fifo < 0 && | |
2b3942e4 | 321 | producer_nice == MAX_NICE && consumer_nice == MAX_NICE) |
7ac07434 SR |
322 | trace_printk("WARNING!!! This test is running at lowest priority.\n"); |
323 | ||
4b221f03 SR |
324 | trace_printk("Time: %lld (usecs)\n", time); |
325 | trace_printk("Overruns: %lld\n", overruns); | |
5092dbc9 | 326 | if (disable_reader) |
4b221f03 | 327 | trace_printk("Read: (reader disabled)\n"); |
5092dbc9 | 328 | else |
4b221f03 | 329 | trace_printk("Read: %ld (by %s)\n", read, |
5092dbc9 | 330 | read_events ? "events" : "pages"); |
4b221f03 SR |
331 | trace_printk("Entries: %lld\n", entries); |
332 | trace_printk("Total: %lld\n", entries + overruns + read); | |
333 | trace_printk("Missed: %ld\n", missed); | |
334 | trace_printk("Hit: %ld\n", hit); | |
5092dbc9 | 335 | |
5a772b2b SR |
336 | /* Convert time from usecs to millisecs */ |
337 | do_div(time, USEC_PER_MSEC); | |
5092dbc9 SR |
338 | if (time) |
339 | hit /= (long)time; | |
340 | else | |
4b221f03 | 341 | trace_printk("TIME IS ZERO??\n"); |
5092dbc9 | 342 | |
4b221f03 | 343 | trace_printk("Entries per millisec: %ld\n", hit); |
5092dbc9 SR |
344 | |
345 | if (hit) { | |
5a772b2b SR |
346 | /* Calculate the average time in nanosecs */ |
347 | avg = NSEC_PER_MSEC / hit; | |
4b221f03 | 348 | trace_printk("%ld ns per entry\n", avg); |
5092dbc9 | 349 | } |
7da3046d | 350 | |
7da3046d SR |
351 | if (missed) { |
352 | if (time) | |
353 | missed /= (long)time; | |
354 | ||
4b221f03 SR |
355 | trace_printk("Total iterations per millisec: %ld\n", |
356 | hit + missed); | |
7da3046d | 357 | |
d988ff94 SR |
358 | /* it is possible that hit + missed will overflow and be zero */ |
359 | if (!(hit + missed)) { | |
4b221f03 | 360 | trace_printk("hit + missed overflowed and totalled zero!\n"); |
d988ff94 SR |
361 | hit--; /* make it non zero */ |
362 | } | |
363 | ||
5a772b2b SR |
364 | /* Caculate the average time in nanosecs */ |
365 | avg = NSEC_PER_MSEC / (hit + missed); | |
4b221f03 | 366 | trace_printk("%ld ns per entry\n", avg); |
7da3046d | 367 | } |
5092dbc9 SR |
368 | } |
369 | ||
370 | static void wait_to_die(void) | |
371 | { | |
372 | set_current_state(TASK_INTERRUPTIBLE); | |
373 | while (!kthread_should_stop()) { | |
374 | schedule(); | |
375 | set_current_state(TASK_INTERRUPTIBLE); | |
376 | } | |
377 | __set_current_state(TASK_RUNNING); | |
378 | } | |
379 | ||
380 | static int ring_buffer_consumer_thread(void *arg) | |
381 | { | |
f47cb66d | 382 | while (!break_test()) { |
5092dbc9 SR |
383 | complete(&read_start); |
384 | ||
385 | ring_buffer_consumer(); | |
386 | ||
387 | set_current_state(TASK_INTERRUPTIBLE); | |
f47cb66d | 388 | if (break_test()) |
5092dbc9 | 389 | break; |
5092dbc9 | 390 | schedule(); |
5092dbc9 SR |
391 | } |
392 | __set_current_state(TASK_RUNNING); | |
393 | ||
b44754d8 | 394 | if (!kthread_should_stop()) |
5092dbc9 SR |
395 | wait_to_die(); |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
400 | static int ring_buffer_producer_thread(void *arg) | |
401 | { | |
f47cb66d | 402 | while (!break_test()) { |
5092dbc9 SR |
403 | ring_buffer_reset(buffer); |
404 | ||
405 | if (consumer) { | |
5092dbc9 SR |
406 | wake_up_process(consumer); |
407 | wait_for_completion(&read_start); | |
408 | } | |
409 | ||
410 | ring_buffer_producer(); | |
f47cb66d | 411 | if (break_test()) |
b44754d8 | 412 | goto out_kill; |
5092dbc9 | 413 | |
4b221f03 | 414 | trace_printk("Sleeping for 10 secs\n"); |
5092dbc9 | 415 | set_current_state(TASK_INTERRUPTIBLE); |
f47cb66d PM |
416 | if (break_test()) |
417 | goto out_kill; | |
5092dbc9 | 418 | schedule_timeout(HZ * SLEEP_TIME); |
5092dbc9 SR |
419 | } |
420 | ||
b44754d8 | 421 | out_kill: |
f47cb66d | 422 | __set_current_state(TASK_RUNNING); |
b44754d8 | 423 | if (!kthread_should_stop()) |
5092dbc9 SR |
424 | wait_to_die(); |
425 | ||
426 | return 0; | |
427 | } | |
428 | ||
429 | static int __init ring_buffer_benchmark_init(void) | |
430 | { | |
431 | int ret; | |
432 | ||
433 | /* make a one meg buffer in overwite mode */ | |
434 | buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE); | |
435 | if (!buffer) | |
436 | return -ENOMEM; | |
437 | ||
438 | if (!disable_reader) { | |
439 | consumer = kthread_create(ring_buffer_consumer_thread, | |
440 | NULL, "rb_consumer"); | |
441 | ret = PTR_ERR(consumer); | |
442 | if (IS_ERR(consumer)) | |
443 | goto out_fail; | |
444 | } | |
445 | ||
446 | producer = kthread_run(ring_buffer_producer_thread, | |
447 | NULL, "rb_producer"); | |
448 | ret = PTR_ERR(producer); | |
449 | ||
450 | if (IS_ERR(producer)) | |
451 | goto out_kill; | |
452 | ||
98e4833b IM |
453 | /* |
454 | * Run them as low-prio background tasks by default: | |
455 | */ | |
7ac07434 SR |
456 | if (!disable_reader) { |
457 | if (consumer_fifo >= 0) { | |
458 | struct sched_param param = { | |
459 | .sched_priority = consumer_fifo | |
460 | }; | |
461 | sched_setscheduler(consumer, SCHED_FIFO, ¶m); | |
462 | } else | |
463 | set_user_nice(consumer, consumer_nice); | |
464 | } | |
465 | ||
466 | if (producer_fifo >= 0) { | |
467 | struct sched_param param = { | |
10802932 | 468 | .sched_priority = producer_fifo |
7ac07434 SR |
469 | }; |
470 | sched_setscheduler(producer, SCHED_FIFO, ¶m); | |
471 | } else | |
472 | set_user_nice(producer, producer_nice); | |
98e4833b | 473 | |
5092dbc9 SR |
474 | return 0; |
475 | ||
476 | out_kill: | |
477 | if (consumer) | |
478 | kthread_stop(consumer); | |
479 | ||
480 | out_fail: | |
481 | ring_buffer_free(buffer); | |
482 | return ret; | |
483 | } | |
484 | ||
485 | static void __exit ring_buffer_benchmark_exit(void) | |
486 | { | |
487 | kthread_stop(producer); | |
488 | if (consumer) | |
489 | kthread_stop(consumer); | |
490 | ring_buffer_free(buffer); | |
491 | } | |
492 | ||
493 | module_init(ring_buffer_benchmark_init); | |
494 | module_exit(ring_buffer_benchmark_exit); | |
495 | ||
496 | MODULE_AUTHOR("Steven Rostedt"); | |
497 | MODULE_DESCRIPTION("ring_buffer_benchmark"); | |
498 | MODULE_LICENSE("GPL"); |