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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 <uapi/linux/sched/types.h>
10#include <linux/module.h>
11#include <linux/ktime.h>
12#include <asm/local.h>
13
14struct rb_page {
15 u64 ts;
16 local_t commit;
17 char data[4080];
18};
19
20/* run time and sleep time in seconds */
21#define RUN_TIME 10ULL
22#define SLEEP_TIME 10
23
24/* number of events for writer to wake up the reader */
25static int wakeup_interval = 100;
26
27static int reader_finish;
28static DECLARE_COMPLETION(read_start);
29static DECLARE_COMPLETION(read_done);
30
31static struct ring_buffer *buffer;
32static struct task_struct *producer;
33static struct task_struct *consumer;
34static unsigned long read;
35
36static unsigned int disable_reader;
37module_param(disable_reader, uint, 0644);
38MODULE_PARM_DESC(disable_reader, "only run producer");
39
40static unsigned int write_iteration = 50;
41module_param(write_iteration, uint, 0644);
42MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
43
44static int producer_nice = MAX_NICE;
45static int consumer_nice = MAX_NICE;
46
47static int producer_fifo = -1;
48static int consumer_fifo = -1;
49
50module_param(producer_nice, int, 0644);
51MODULE_PARM_DESC(producer_nice, "nice prio for producer");
52
53module_param(consumer_nice, int, 0644);
54MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
55
56module_param(producer_fifo, int, 0644);
57MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
58
59module_param(consumer_fifo, int, 0644);
60MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
61
62static int read_events;
63
64static int test_error;
65
66#define TEST_ERROR() \
67 do { \
68 if (!test_error) { \
69 test_error = 1; \
70 WARN_ON(1); \
71 } \
72 } while (0)
73
74enum event_status {
75 EVENT_FOUND,
76 EVENT_DROPPED,
77};
78
79static bool break_test(void)
80{
81 return test_error || kthread_should_stop();
82}
83
84static enum event_status read_event(int cpu)
85{
86 struct ring_buffer_event *event;
87 int *entry;
88 u64 ts;
89
90 event = ring_buffer_consume(buffer, cpu, &ts, NULL);
91 if (!event)
92 return EVENT_DROPPED;
93
94 entry = ring_buffer_event_data(event);
95 if (*entry != cpu) {
96 TEST_ERROR();
97 return EVENT_DROPPED;
98 }
99
100 read++;
101 return EVENT_FOUND;
102}
103
104static 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
115 bpage = ring_buffer_alloc_read_page(buffer, cpu);
116 if (IS_ERR(bpage))
117 return EVENT_DROPPED;
118
119 ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
120 if (ret >= 0) {
121 rpage = bpage;
122 /* The commit may have missed event flags set, clear them */
123 commit = local_read(&rpage->commit) & 0xfffff;
124 for (i = 0; i < commit && !test_error ; i += inc) {
125
126 if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
127 TEST_ERROR();
128 break;
129 }
130
131 inc = -1;
132 event = (void *)&rpage->data[i];
133 switch (event->type_len) {
134 case RINGBUF_TYPE_PADDING:
135 /* failed writes may be discarded events */
136 if (!event->time_delta)
137 TEST_ERROR();
138 inc = event->array[0] + 4;
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) {
146 TEST_ERROR();
147 break;
148 }
149 read++;
150 if (!event->array[0]) {
151 TEST_ERROR();
152 break;
153 }
154 inc = event->array[0] + 4;
155 break;
156 default:
157 entry = ring_buffer_event_data(event);
158 if (*entry != cpu) {
159 TEST_ERROR();
160 break;
161 }
162 read++;
163 inc = ((event->type_len + 1) * 4);
164 }
165 if (test_error)
166 break;
167
168 if (inc <= 0) {
169 TEST_ERROR();
170 break;
171 }
172 }
173 }
174 ring_buffer_free_read_page(buffer, cpu, bpage);
175
176 if (ret < 0)
177 return EVENT_DROPPED;
178 return EVENT_FOUND;
179}
180
181static void ring_buffer_consumer(void)
182{
183 /* toggle between reading pages and events */
184 read_events ^= 1;
185
186 read = 0;
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;
193
194 while (found && !test_error) {
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
206 if (test_error)
207 break;
208
209 if (stat == EVENT_FOUND)
210 found = 1;
211
212 }
213 }
214
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 */
218 set_current_state(TASK_INTERRUPTIBLE);
219 if (reader_finish)
220 break;
221
222 schedule();
223 }
224 __set_current_state(TASK_RUNNING);
225 reader_finish = 0;
226 complete(&read_done);
227}
228
229static void ring_buffer_producer(void)
230{
231 ktime_t start_time, end_time, timeout;
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 */
244 trace_printk("Starting ring buffer hammer\n");
245 start_time = ktime_get();
246 timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
247 do {
248 struct ring_buffer_event *event;
249 int *entry;
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 }
262 }
263 end_time = ktime_get();
264
265 cnt++;
266 if (consumer && !(cnt % wakeup_interval))
267 wake_up_process(consumer);
268
269#ifndef CONFIG_PREEMPT
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.
275 *
276 * Do a cond resched at the same frequency we would wake up
277 * the reader.
278 */
279 if (cnt % wakeup_interval)
280 cond_resched();
281#endif
282 } while (ktime_before(end_time, timeout) && !break_test());
283 trace_printk("End ring buffer hammer\n");
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;
292 wake_up_process(consumer);
293 wait_for_completion(&read_done);
294 }
295
296 time = ktime_us_delta(end_time, start_time);
297
298 entries = ring_buffer_entries(buffer);
299 overruns = ring_buffer_overruns(buffer);
300
301 if (test_error)
302 trace_printk("ERROR!\n");
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 &&
321 producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
322 trace_printk("WARNING!!! This test is running at lowest priority.\n");
323
324 trace_printk("Time: %lld (usecs)\n", time);
325 trace_printk("Overruns: %lld\n", overruns);
326 if (disable_reader)
327 trace_printk("Read: (reader disabled)\n");
328 else
329 trace_printk("Read: %ld (by %s)\n", read,
330 read_events ? "events" : "pages");
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);
335
336 /* Convert time from usecs to millisecs */
337 do_div(time, USEC_PER_MSEC);
338 if (time)
339 hit /= (long)time;
340 else
341 trace_printk("TIME IS ZERO??\n");
342
343 trace_printk("Entries per millisec: %ld\n", hit);
344
345 if (hit) {
346 /* Calculate the average time in nanosecs */
347 avg = NSEC_PER_MSEC / hit;
348 trace_printk("%ld ns per entry\n", avg);
349 }
350
351 if (missed) {
352 if (time)
353 missed /= (long)time;
354
355 trace_printk("Total iterations per millisec: %ld\n",
356 hit + missed);
357
358 /* it is possible that hit + missed will overflow and be zero */
359 if (!(hit + missed)) {
360 trace_printk("hit + missed overflowed and totalled zero!\n");
361 hit--; /* make it non zero */
362 }
363
364 /* Caculate the average time in nanosecs */
365 avg = NSEC_PER_MSEC / (hit + missed);
366 trace_printk("%ld ns per entry\n", avg);
367 }
368}
369
370static 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
380static int ring_buffer_consumer_thread(void *arg)
381{
382 while (!break_test()) {
383 complete(&read_start);
384
385 ring_buffer_consumer();
386
387 set_current_state(TASK_INTERRUPTIBLE);
388 if (break_test())
389 break;
390 schedule();
391 }
392 __set_current_state(TASK_RUNNING);
393
394 if (!kthread_should_stop())
395 wait_to_die();
396
397 return 0;
398}
399
400static int ring_buffer_producer_thread(void *arg)
401{
402 while (!break_test()) {
403 ring_buffer_reset(buffer);
404
405 if (consumer) {
406 wake_up_process(consumer);
407 wait_for_completion(&read_start);
408 }
409
410 ring_buffer_producer();
411 if (break_test())
412 goto out_kill;
413
414 trace_printk("Sleeping for 10 secs\n");
415 set_current_state(TASK_INTERRUPTIBLE);
416 if (break_test())
417 goto out_kill;
418 schedule_timeout(HZ * SLEEP_TIME);
419 }
420
421out_kill:
422 __set_current_state(TASK_RUNNING);
423 if (!kthread_should_stop())
424 wait_to_die();
425
426 return 0;
427}
428
429static 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
453 /*
454 * Run them as low-prio background tasks by default:
455 */
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 = {
468 .sched_priority = producer_fifo
469 };
470 sched_setscheduler(producer, SCHED_FIFO, ¶m);
471 } else
472 set_user_nice(producer, producer_nice);
473
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
485static 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
493module_init(ring_buffer_benchmark_init);
494module_exit(ring_buffer_benchmark_exit);
495
496MODULE_AUTHOR("Steven Rostedt");
497MODULE_DESCRIPTION("ring_buffer_benchmark");
498MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer tester and benchmark
4 *
5 * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
6 */
7#include <linux/ring_buffer.h>
8#include <linux/completion.h>
9#include <linux/kthread.h>
10#include <uapi/linux/sched/types.h>
11#include <linux/module.h>
12#include <linux/ktime.h>
13#include <asm/local.h>
14
15struct rb_page {
16 u64 ts;
17 local_t commit;
18 char data[4080];
19};
20
21/* run time and sleep time in seconds */
22#define RUN_TIME 10ULL
23#define SLEEP_TIME 10
24
25/* number of events for writer to wake up the reader */
26static int wakeup_interval = 100;
27
28static int reader_finish;
29static DECLARE_COMPLETION(read_start);
30static DECLARE_COMPLETION(read_done);
31
32static struct trace_buffer *buffer;
33static struct task_struct *producer;
34static struct task_struct *consumer;
35static unsigned long read;
36
37static unsigned int disable_reader;
38module_param(disable_reader, uint, 0644);
39MODULE_PARM_DESC(disable_reader, "only run producer");
40
41static unsigned int write_iteration = 50;
42module_param(write_iteration, uint, 0644);
43MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
44
45static int producer_nice = MAX_NICE;
46static int consumer_nice = MAX_NICE;
47
48static int producer_fifo;
49static int consumer_fifo;
50
51module_param(producer_nice, int, 0644);
52MODULE_PARM_DESC(producer_nice, "nice prio for producer");
53
54module_param(consumer_nice, int, 0644);
55MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
56
57module_param(producer_fifo, int, 0644);
58MODULE_PARM_DESC(producer_fifo, "use fifo for producer: 0 - disabled, 1 - low prio, 2 - fifo");
59
60module_param(consumer_fifo, int, 0644);
61MODULE_PARM_DESC(consumer_fifo, "use fifo for consumer: 0 - disabled, 1 - low prio, 2 - fifo");
62
63static int read_events;
64
65static int test_error;
66
67#define TEST_ERROR() \
68 do { \
69 if (!test_error) { \
70 test_error = 1; \
71 WARN_ON(1); \
72 } \
73 } while (0)
74
75enum event_status {
76 EVENT_FOUND,
77 EVENT_DROPPED,
78};
79
80static bool break_test(void)
81{
82 return test_error || kthread_should_stop();
83}
84
85static enum event_status read_event(int cpu)
86{
87 struct ring_buffer_event *event;
88 int *entry;
89 u64 ts;
90
91 event = ring_buffer_consume(buffer, cpu, &ts, NULL);
92 if (!event)
93 return EVENT_DROPPED;
94
95 entry = ring_buffer_event_data(event);
96 if (*entry != cpu) {
97 TEST_ERROR();
98 return EVENT_DROPPED;
99 }
100
101 read++;
102 return EVENT_FOUND;
103}
104
105static enum event_status read_page(int cpu)
106{
107 struct ring_buffer_event *event;
108 struct rb_page *rpage;
109 unsigned long commit;
110 void *bpage;
111 int *entry;
112 int ret;
113 int inc;
114 int i;
115
116 bpage = ring_buffer_alloc_read_page(buffer, cpu);
117 if (IS_ERR(bpage))
118 return EVENT_DROPPED;
119
120 ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
121 if (ret >= 0) {
122 rpage = bpage;
123 /* The commit may have missed event flags set, clear them */
124 commit = local_read(&rpage->commit) & 0xfffff;
125 for (i = 0; i < commit && !test_error ; i += inc) {
126
127 if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
128 TEST_ERROR();
129 break;
130 }
131
132 inc = -1;
133 event = (void *)&rpage->data[i];
134 switch (event->type_len) {
135 case RINGBUF_TYPE_PADDING:
136 /* failed writes may be discarded events */
137 if (!event->time_delta)
138 TEST_ERROR();
139 inc = event->array[0] + 4;
140 break;
141 case RINGBUF_TYPE_TIME_EXTEND:
142 inc = 8;
143 break;
144 case 0:
145 entry = ring_buffer_event_data(event);
146 if (*entry != cpu) {
147 TEST_ERROR();
148 break;
149 }
150 read++;
151 if (!event->array[0]) {
152 TEST_ERROR();
153 break;
154 }
155 inc = event->array[0] + 4;
156 break;
157 default:
158 entry = ring_buffer_event_data(event);
159 if (*entry != cpu) {
160 TEST_ERROR();
161 break;
162 }
163 read++;
164 inc = ((event->type_len + 1) * 4);
165 }
166 if (test_error)
167 break;
168
169 if (inc <= 0) {
170 TEST_ERROR();
171 break;
172 }
173 }
174 }
175 ring_buffer_free_read_page(buffer, cpu, bpage);
176
177 if (ret < 0)
178 return EVENT_DROPPED;
179 return EVENT_FOUND;
180}
181
182static void ring_buffer_consumer(void)
183{
184 /* toggle between reading pages and events */
185 read_events ^= 1;
186
187 read = 0;
188 /*
189 * Continue running until the producer specifically asks to stop
190 * and is ready for the completion.
191 */
192 while (!READ_ONCE(reader_finish)) {
193 int found = 1;
194
195 while (found && !test_error) {
196 int cpu;
197
198 found = 0;
199 for_each_online_cpu(cpu) {
200 enum event_status stat;
201
202 if (read_events)
203 stat = read_event(cpu);
204 else
205 stat = read_page(cpu);
206
207 if (test_error)
208 break;
209
210 if (stat == EVENT_FOUND)
211 found = 1;
212
213 }
214 }
215
216 /* Wait till the producer wakes us up when there is more data
217 * available or when the producer wants us to finish reading.
218 */
219 set_current_state(TASK_INTERRUPTIBLE);
220 if (reader_finish)
221 break;
222
223 schedule();
224 }
225 __set_current_state(TASK_RUNNING);
226 reader_finish = 0;
227 complete(&read_done);
228}
229
230static void ring_buffer_producer(void)
231{
232 ktime_t start_time, end_time, timeout;
233 unsigned long long time;
234 unsigned long long entries;
235 unsigned long long overruns;
236 unsigned long missed = 0;
237 unsigned long hit = 0;
238 unsigned long avg;
239 int cnt = 0;
240
241 /*
242 * Hammer the buffer for 10 secs (this may
243 * make the system stall)
244 */
245 trace_printk("Starting ring buffer hammer\n");
246 start_time = ktime_get();
247 timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
248 do {
249 struct ring_buffer_event *event;
250 int *entry;
251 int i;
252
253 for (i = 0; i < write_iteration; i++) {
254 event = ring_buffer_lock_reserve(buffer, 10);
255 if (!event) {
256 missed++;
257 } else {
258 hit++;
259 entry = ring_buffer_event_data(event);
260 *entry = smp_processor_id();
261 ring_buffer_unlock_commit(buffer);
262 }
263 }
264 end_time = ktime_get();
265
266 cnt++;
267 if (consumer && !(cnt % wakeup_interval))
268 wake_up_process(consumer);
269
270#ifndef CONFIG_PREEMPTION
271 /*
272 * If we are a non preempt kernel, the 10 seconds run will
273 * stop everything while it runs. Instead, we will call
274 * cond_resched and also add any time that was lost by a
275 * reschedule.
276 *
277 * Do a cond resched at the same frequency we would wake up
278 * the reader.
279 */
280 if (cnt % wakeup_interval)
281 cond_resched();
282#endif
283 } while (ktime_before(end_time, timeout) && !break_test());
284 trace_printk("End ring buffer hammer\n");
285
286 if (consumer) {
287 /* Init both completions here to avoid races */
288 init_completion(&read_start);
289 init_completion(&read_done);
290 /* the completions must be visible before the finish var */
291 smp_wmb();
292 reader_finish = 1;
293 wake_up_process(consumer);
294 wait_for_completion(&read_done);
295 }
296
297 time = ktime_us_delta(end_time, start_time);
298
299 entries = ring_buffer_entries(buffer);
300 overruns = ring_buffer_overruns(buffer);
301
302 if (test_error)
303 trace_printk("ERROR!\n");
304
305 if (!disable_reader) {
306 if (consumer_fifo)
307 trace_printk("Running Consumer at SCHED_FIFO %s\n",
308 consumer_fifo == 1 ? "low" : "high");
309 else
310 trace_printk("Running Consumer at nice: %d\n",
311 consumer_nice);
312 }
313 if (producer_fifo)
314 trace_printk("Running Producer at SCHED_FIFO %s\n",
315 producer_fifo == 1 ? "low" : "high");
316 else
317 trace_printk("Running Producer at nice: %d\n",
318 producer_nice);
319
320 /* Let the user know that the test is running at low priority */
321 if (!producer_fifo && !consumer_fifo &&
322 producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
323 trace_printk("WARNING!!! This test is running at lowest priority.\n");
324
325 trace_printk("Time: %lld (usecs)\n", time);
326 trace_printk("Overruns: %lld\n", overruns);
327 if (disable_reader)
328 trace_printk("Read: (reader disabled)\n");
329 else
330 trace_printk("Read: %ld (by %s)\n", read,
331 read_events ? "events" : "pages");
332 trace_printk("Entries: %lld\n", entries);
333 trace_printk("Total: %lld\n", entries + overruns + read);
334 trace_printk("Missed: %ld\n", missed);
335 trace_printk("Hit: %ld\n", hit);
336
337 /* Convert time from usecs to millisecs */
338 do_div(time, USEC_PER_MSEC);
339 if (time)
340 hit /= (long)time;
341 else
342 trace_printk("TIME IS ZERO??\n");
343
344 trace_printk("Entries per millisec: %ld\n", hit);
345
346 if (hit) {
347 /* Calculate the average time in nanosecs */
348 avg = NSEC_PER_MSEC / hit;
349 trace_printk("%ld ns per entry\n", avg);
350 }
351
352 if (missed) {
353 if (time)
354 missed /= (long)time;
355
356 trace_printk("Total iterations per millisec: %ld\n",
357 hit + missed);
358
359 /* it is possible that hit + missed will overflow and be zero */
360 if (!(hit + missed)) {
361 trace_printk("hit + missed overflowed and totalled zero!\n");
362 hit--; /* make it non zero */
363 }
364
365 /* Calculate the average time in nanosecs */
366 avg = NSEC_PER_MSEC / (hit + missed);
367 trace_printk("%ld ns per entry\n", avg);
368 }
369}
370
371static void wait_to_die(void)
372{
373 set_current_state(TASK_INTERRUPTIBLE);
374 while (!kthread_should_stop()) {
375 schedule();
376 set_current_state(TASK_INTERRUPTIBLE);
377 }
378 __set_current_state(TASK_RUNNING);
379}
380
381static int ring_buffer_consumer_thread(void *arg)
382{
383 while (!break_test()) {
384 complete(&read_start);
385
386 ring_buffer_consumer();
387
388 set_current_state(TASK_INTERRUPTIBLE);
389 if (break_test())
390 break;
391 schedule();
392 }
393 __set_current_state(TASK_RUNNING);
394
395 if (!kthread_should_stop())
396 wait_to_die();
397
398 return 0;
399}
400
401static int ring_buffer_producer_thread(void *arg)
402{
403 while (!break_test()) {
404 ring_buffer_reset(buffer);
405
406 if (consumer) {
407 wake_up_process(consumer);
408 wait_for_completion(&read_start);
409 }
410
411 ring_buffer_producer();
412 if (break_test())
413 goto out_kill;
414
415 trace_printk("Sleeping for 10 secs\n");
416 set_current_state(TASK_INTERRUPTIBLE);
417 if (break_test())
418 goto out_kill;
419 schedule_timeout(HZ * SLEEP_TIME);
420 }
421
422out_kill:
423 __set_current_state(TASK_RUNNING);
424 if (!kthread_should_stop())
425 wait_to_die();
426
427 return 0;
428}
429
430static int __init ring_buffer_benchmark_init(void)
431{
432 int ret;
433
434 /* make a one meg buffer in overwite mode */
435 buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
436 if (!buffer)
437 return -ENOMEM;
438
439 if (!disable_reader) {
440 consumer = kthread_create(ring_buffer_consumer_thread,
441 NULL, "rb_consumer");
442 ret = PTR_ERR(consumer);
443 if (IS_ERR(consumer))
444 goto out_fail;
445 }
446
447 producer = kthread_run(ring_buffer_producer_thread,
448 NULL, "rb_producer");
449 ret = PTR_ERR(producer);
450
451 if (IS_ERR(producer))
452 goto out_kill;
453
454 /*
455 * Run them as low-prio background tasks by default:
456 */
457 if (!disable_reader) {
458 if (consumer_fifo >= 2)
459 sched_set_fifo(consumer);
460 else if (consumer_fifo == 1)
461 sched_set_fifo_low(consumer);
462 else
463 set_user_nice(consumer, consumer_nice);
464 }
465
466 if (producer_fifo >= 2)
467 sched_set_fifo(producer);
468 else if (producer_fifo == 1)
469 sched_set_fifo_low(producer);
470 else
471 set_user_nice(producer, producer_nice);
472
473 return 0;
474
475 out_kill:
476 if (consumer)
477 kthread_stop(consumer);
478
479 out_fail:
480 ring_buffer_free(buffer);
481 return ret;
482}
483
484static void __exit ring_buffer_benchmark_exit(void)
485{
486 kthread_stop(producer);
487 if (consumer)
488 kthread_stop(consumer);
489 ring_buffer_free(buffer);
490}
491
492module_init(ring_buffer_benchmark_init);
493module_exit(ring_buffer_benchmark_exit);
494
495MODULE_AUTHOR("Steven Rostedt");
496MODULE_DESCRIPTION("ring_buffer_benchmark");
497MODULE_LICENSE("GPL");