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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 buffer_data_read_page *bpage;
108 struct ring_buffer_event *event;
109 struct rb_page *rpage;
110 unsigned long commit;
111 int page_size;
112 int *entry;
113 int ret;
114 int inc;
115 int i;
116
117 bpage = ring_buffer_alloc_read_page(buffer, cpu);
118 if (IS_ERR(bpage))
119 return EVENT_DROPPED;
120
121 page_size = ring_buffer_subbuf_size_get(buffer);
122 ret = ring_buffer_read_page(buffer, bpage, page_size, cpu, 1);
123 if (ret >= 0) {
124 rpage = ring_buffer_read_page_data(bpage);
125 /* The commit may have missed event flags set, clear them */
126 commit = local_read(&rpage->commit) & 0xfffff;
127 for (i = 0; i < commit && !test_error ; i += inc) {
128
129 if (i >= (page_size - offsetof(struct rb_page, data))) {
130 TEST_ERROR();
131 break;
132 }
133
134 inc = -1;
135 event = (void *)&rpage->data[i];
136 switch (event->type_len) {
137 case RINGBUF_TYPE_PADDING:
138 /* failed writes may be discarded events */
139 if (!event->time_delta)
140 TEST_ERROR();
141 inc = event->array[0] + 4;
142 break;
143 case RINGBUF_TYPE_TIME_EXTEND:
144 inc = 8;
145 break;
146 case 0:
147 entry = ring_buffer_event_data(event);
148 if (*entry != cpu) {
149 TEST_ERROR();
150 break;
151 }
152 read++;
153 if (!event->array[0]) {
154 TEST_ERROR();
155 break;
156 }
157 inc = event->array[0] + 4;
158 break;
159 default:
160 entry = ring_buffer_event_data(event);
161 if (*entry != cpu) {
162 TEST_ERROR();
163 break;
164 }
165 read++;
166 inc = ((event->type_len + 1) * 4);
167 }
168 if (test_error)
169 break;
170
171 if (inc <= 0) {
172 TEST_ERROR();
173 break;
174 }
175 }
176 }
177 ring_buffer_free_read_page(buffer, cpu, bpage);
178
179 if (ret < 0)
180 return EVENT_DROPPED;
181 return EVENT_FOUND;
182}
183
184static void ring_buffer_consumer(void)
185{
186 /* toggle between reading pages and events */
187 read_events ^= 1;
188
189 read = 0;
190 /*
191 * Continue running until the producer specifically asks to stop
192 * and is ready for the completion.
193 */
194 while (!READ_ONCE(reader_finish)) {
195 int found = 1;
196
197 while (found && !test_error) {
198 int cpu;
199
200 found = 0;
201 for_each_online_cpu(cpu) {
202 enum event_status stat;
203
204 if (read_events)
205 stat = read_event(cpu);
206 else
207 stat = read_page(cpu);
208
209 if (test_error)
210 break;
211
212 if (stat == EVENT_FOUND)
213 found = 1;
214
215 }
216 }
217
218 /* Wait till the producer wakes us up when there is more data
219 * available or when the producer wants us to finish reading.
220 */
221 set_current_state(TASK_INTERRUPTIBLE);
222 if (reader_finish)
223 break;
224
225 schedule();
226 }
227 __set_current_state(TASK_RUNNING);
228 reader_finish = 0;
229 complete(&read_done);
230}
231
232static void ring_buffer_producer(void)
233{
234 ktime_t start_time, end_time, timeout;
235 unsigned long long time;
236 unsigned long long entries;
237 unsigned long long overruns;
238 unsigned long missed = 0;
239 unsigned long hit = 0;
240 unsigned long avg;
241 int cnt = 0;
242
243 /*
244 * Hammer the buffer for 10 secs (this may
245 * make the system stall)
246 */
247 trace_printk("Starting ring buffer hammer\n");
248 start_time = ktime_get();
249 timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
250 do {
251 struct ring_buffer_event *event;
252 int *entry;
253 int i;
254
255 for (i = 0; i < write_iteration; i++) {
256 event = ring_buffer_lock_reserve(buffer, 10);
257 if (!event) {
258 missed++;
259 } else {
260 hit++;
261 entry = ring_buffer_event_data(event);
262 *entry = smp_processor_id();
263 ring_buffer_unlock_commit(buffer);
264 }
265 }
266 end_time = ktime_get();
267
268 cnt++;
269 if (consumer && !(cnt % wakeup_interval))
270 wake_up_process(consumer);
271
272#ifndef CONFIG_PREEMPTION
273 /*
274 * If we are a non preempt kernel, the 10 seconds run will
275 * stop everything while it runs. Instead, we will call
276 * cond_resched and also add any time that was lost by a
277 * reschedule.
278 *
279 * Do a cond resched at the same frequency we would wake up
280 * the reader.
281 */
282 if (cnt % wakeup_interval)
283 cond_resched();
284#endif
285 } while (ktime_before(end_time, timeout) && !break_test());
286 trace_printk("End ring buffer hammer\n");
287
288 if (consumer) {
289 /* Init both completions here to avoid races */
290 init_completion(&read_start);
291 init_completion(&read_done);
292 /* the completions must be visible before the finish var */
293 smp_wmb();
294 reader_finish = 1;
295 wake_up_process(consumer);
296 wait_for_completion(&read_done);
297 }
298
299 time = ktime_us_delta(end_time, start_time);
300
301 entries = ring_buffer_entries(buffer);
302 overruns = ring_buffer_overruns(buffer);
303
304 if (test_error)
305 trace_printk("ERROR!\n");
306
307 if (!disable_reader) {
308 if (consumer_fifo)
309 trace_printk("Running Consumer at SCHED_FIFO %s\n",
310 str_low_high(consumer_fifo == 1));
311 else
312 trace_printk("Running Consumer at nice: %d\n",
313 consumer_nice);
314 }
315 if (producer_fifo)
316 trace_printk("Running Producer at SCHED_FIFO %s\n",
317 str_low_high(producer_fifo == 1));
318 else
319 trace_printk("Running Producer at nice: %d\n",
320 producer_nice);
321
322 /* Let the user know that the test is running at low priority */
323 if (!producer_fifo && !consumer_fifo &&
324 producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
325 trace_printk("WARNING!!! This test is running at lowest priority.\n");
326
327 trace_printk("Time: %lld (usecs)\n", time);
328 trace_printk("Overruns: %lld\n", overruns);
329 if (disable_reader)
330 trace_printk("Read: (reader disabled)\n");
331 else
332 trace_printk("Read: %ld (by %s)\n", read,
333 read_events ? "events" : "pages");
334 trace_printk("Entries: %lld\n", entries);
335 trace_printk("Total: %lld\n", entries + overruns + read);
336 trace_printk("Missed: %ld\n", missed);
337 trace_printk("Hit: %ld\n", hit);
338
339 /* Convert time from usecs to millisecs */
340 do_div(time, USEC_PER_MSEC);
341 if (time)
342 hit /= (long)time;
343 else
344 trace_printk("TIME IS ZERO??\n");
345
346 trace_printk("Entries per millisec: %ld\n", hit);
347
348 if (hit) {
349 /* Calculate the average time in nanosecs */
350 avg = NSEC_PER_MSEC / hit;
351 trace_printk("%ld ns per entry\n", avg);
352 }
353
354 if (missed) {
355 if (time)
356 missed /= (long)time;
357
358 trace_printk("Total iterations per millisec: %ld\n",
359 hit + missed);
360
361 /* it is possible that hit + missed will overflow and be zero */
362 if (!(hit + missed)) {
363 trace_printk("hit + missed overflowed and totalled zero!\n");
364 hit--; /* make it non zero */
365 }
366
367 /* Calculate the average time in nanosecs */
368 avg = NSEC_PER_MSEC / (hit + missed);
369 trace_printk("%ld ns per entry\n", avg);
370 }
371}
372
373static void wait_to_die(void)
374{
375 set_current_state(TASK_INTERRUPTIBLE);
376 while (!kthread_should_stop()) {
377 schedule();
378 set_current_state(TASK_INTERRUPTIBLE);
379 }
380 __set_current_state(TASK_RUNNING);
381}
382
383static int ring_buffer_consumer_thread(void *arg)
384{
385 while (!break_test()) {
386 complete(&read_start);
387
388 ring_buffer_consumer();
389
390 set_current_state(TASK_INTERRUPTIBLE);
391 if (break_test())
392 break;
393 schedule();
394 }
395 __set_current_state(TASK_RUNNING);
396
397 if (!kthread_should_stop())
398 wait_to_die();
399
400 return 0;
401}
402
403static int ring_buffer_producer_thread(void *arg)
404{
405 while (!break_test()) {
406 ring_buffer_reset(buffer);
407
408 if (consumer) {
409 wake_up_process(consumer);
410 wait_for_completion(&read_start);
411 }
412
413 ring_buffer_producer();
414 if (break_test())
415 goto out_kill;
416
417 trace_printk("Sleeping for 10 secs\n");
418 set_current_state(TASK_INTERRUPTIBLE);
419 if (break_test())
420 goto out_kill;
421 schedule_timeout(HZ * SLEEP_TIME);
422 }
423
424out_kill:
425 __set_current_state(TASK_RUNNING);
426 if (!kthread_should_stop())
427 wait_to_die();
428
429 return 0;
430}
431
432static int __init ring_buffer_benchmark_init(void)
433{
434 int ret;
435
436 /* make a one meg buffer in overwite mode */
437 buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
438 if (!buffer)
439 return -ENOMEM;
440
441 if (!disable_reader) {
442 consumer = kthread_create(ring_buffer_consumer_thread,
443 NULL, "rb_consumer");
444 ret = PTR_ERR(consumer);
445 if (IS_ERR(consumer))
446 goto out_fail;
447 }
448
449 producer = kthread_run(ring_buffer_producer_thread,
450 NULL, "rb_producer");
451 ret = PTR_ERR(producer);
452
453 if (IS_ERR(producer))
454 goto out_kill;
455
456 /*
457 * Run them as low-prio background tasks by default:
458 */
459 if (!disable_reader) {
460 if (consumer_fifo >= 2)
461 sched_set_fifo(consumer);
462 else if (consumer_fifo == 1)
463 sched_set_fifo_low(consumer);
464 else
465 set_user_nice(consumer, consumer_nice);
466 }
467
468 if (producer_fifo >= 2)
469 sched_set_fifo(producer);
470 else if (producer_fifo == 1)
471 sched_set_fifo_low(producer);
472 else
473 set_user_nice(producer, producer_nice);
474
475 return 0;
476
477 out_kill:
478 if (consumer)
479 kthread_stop(consumer);
480
481 out_fail:
482 ring_buffer_free(buffer);
483 return ret;
484}
485
486static void __exit ring_buffer_benchmark_exit(void)
487{
488 kthread_stop(producer);
489 if (consumer)
490 kthread_stop(consumer);
491 ring_buffer_free(buffer);
492}
493
494module_init(ring_buffer_benchmark_init);
495module_exit(ring_buffer_benchmark_exit);
496
497MODULE_AUTHOR("Steven Rostedt");
498MODULE_DESCRIPTION("ring_buffer_benchmark");
499MODULE_LICENSE("GPL");