[linux-2.6-block.git] / kernel / trace / ring_buffer_benchmark.c

/*
 * ring buffer tester and benchmark
 *
 * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
 */
#include <linux/ring_buffer.h>
#include <linux/completion.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/ktime.h>
#include <asm/local.h>

struct rb_page {
	u64		ts;
	local_t		commit;
	char		data[4080];
};

/* run time and sleep time in seconds */
#define RUN_TIME	10ULL
#define SLEEP_TIME	10

/* number of events for writer to wake up the reader */
static int wakeup_interval = 100;

static int reader_finish;
static DECLARE_COMPLETION(read_start);
static DECLARE_COMPLETION(read_done);

static struct ring_buffer *buffer;
static struct task_struct *producer;
static struct task_struct *consumer;
static unsigned long read;

static unsigned int disable_reader;
module_param(disable_reader, uint, 0644);
MODULE_PARM_DESC(disable_reader, "only run producer");

static unsigned int write_iteration = 50;
module_param(write_iteration, uint, 0644);
MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");

static int producer_nice = MAX_NICE;
static int consumer_nice = MAX_NICE;

static int producer_fifo = -1;
static int consumer_fifo = -1;

module_param(producer_nice, int, 0644);
MODULE_PARM_DESC(producer_nice, "nice prio for producer");

module_param(consumer_nice, int, 0644);
MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");

module_param(producer_fifo, int, 0644);
MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");

module_param(consumer_fifo, int, 0644);
MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");

static int read_events;

static int test_error;

#define TEST_ERROR()				\
	do {					\
		if (!test_error) {		\
			test_error = 1;		\
			WARN_ON(1);		\
		}				\
	} while (0)

enum event_status {
	EVENT_FOUND,
	EVENT_DROPPED,
};

static bool break_test(void)
{
	return test_error || kthread_should_stop();
}

static enum event_status read_event(int cpu)
{
	struct ring_buffer_event *event;
	int *entry;
	u64 ts;

	event = ring_buffer_consume(buffer, cpu, &ts, NULL);
	if (!event)
		return EVENT_DROPPED;

	entry = ring_buffer_event_data(event);
	if (*entry != cpu) {
		TEST_ERROR();
		return EVENT_DROPPED;
	}

	read++;
	return EVENT_FOUND;
}

static enum event_status read_page(int cpu)
{
	struct ring_buffer_event *event;
	struct rb_page *rpage;
	unsigned long commit;
	void *bpage;
	int *entry;
	int ret;
	int inc;
	int i;

	bpage = ring_buffer_alloc_read_page(buffer, cpu);
	if (!bpage)
		return EVENT_DROPPED;

	ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
	if (ret >= 0) {
		rpage = bpage;
		/* The commit may have missed event flags set, clear them */
		commit = local_read(&rpage->commit) & 0xfffff;
		for (i = 0; i < commit && !test_error ; i += inc) {

			if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
				TEST_ERROR();
				break;
			}

			inc = -1;
			event = (void *)&rpage->data[i];
			switch (event->type_len) {
			case RINGBUF_TYPE_PADDING:
				/* failed writes may be discarded events */
				if (!event->time_delta)
					TEST_ERROR();
				inc = event->array[0] + 4;
				break;
			case RINGBUF_TYPE_TIME_EXTEND:
				inc = 8;
				break;
			case 0:
				entry = ring_buffer_event_data(event);
				if (*entry != cpu) {
					TEST_ERROR();
					break;
				}
				read++;
				if (!event->array[0]) {
					TEST_ERROR();
					break;
				}
				inc = event->array[0] + 4;
				break;
			default:
				entry = ring_buffer_event_data(event);
				if (*entry != cpu) {
					TEST_ERROR();
					break;
				}
				read++;
				inc = ((event->type_len + 1) * 4);
			}
			if (test_error)
				break;

			if (inc <= 0) {
				TEST_ERROR();
				break;
			}
		}
	}
	ring_buffer_free_read_page(buffer, bpage);

	if (ret < 0)
		return EVENT_DROPPED;
	return EVENT_FOUND;
}

static void ring_buffer_consumer(void)
{
	/* toggle between reading pages and events */
	read_events ^= 1;

	read = 0;
	/*
	 * Continue running until the producer specifically asks to stop
	 * and is ready for the completion.
	 */
	while (!READ_ONCE(reader_finish)) {
		int found = 1;

		while (found && !test_error) {
			int cpu;

			found = 0;
			for_each_online_cpu(cpu) {
				enum event_status stat;

				if (read_events)
					stat = read_event(cpu);
				else
					stat = read_page(cpu);

				if (test_error)
					break;

				if (stat == EVENT_FOUND)
					found = 1;

			}
		}

		/* Wait till the producer wakes us up when there is more data
		 * available or when the producer wants us to finish reading.
		 */
		set_current_state(TASK_INTERRUPTIBLE);
		if (reader_finish)
			break;

		schedule();
	}
	__set_current_state(TASK_RUNNING);
	reader_finish = 0;
	complete(&read_done);
}

static void ring_buffer_producer(void)
{
	ktime_t start_time, end_time, timeout;
	unsigned long long time;
	unsigned long long entries;
	unsigned long long overruns;
	unsigned long missed = 0;
	unsigned long hit = 0;
	unsigned long avg;
	int cnt = 0;

	/*
	 * Hammer the buffer for 10 secs (this may
	 * make the system stall)
	 */
	trace_printk("Starting ring buffer hammer\n");
	start_time = ktime_get();
	timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
	do {
		struct ring_buffer_event *event;
		int *entry;
		int i;

		for (i = 0; i < write_iteration; i++) {
			event = ring_buffer_lock_reserve(buffer, 10);
			if (!event) {
				missed++;
			} else {
				hit++;
				entry = ring_buffer_event_data(event);
				*entry = smp_processor_id();
				ring_buffer_unlock_commit(buffer, event);
			}
		}
		end_time = ktime_get();

		cnt++;
		if (consumer && !(cnt % wakeup_interval))
			wake_up_process(consumer);

#ifndef CONFIG_PREEMPT
		/*
		 * If we are a non preempt kernel, the 10 second run will
		 * stop everything while it runs. Instead, we will call
		 * cond_resched and also add any time that was lost by a
		 * rescedule.
		 *
		 * Do a cond resched at the same frequency we would wake up
		 * the reader.
		 */
		if (cnt % wakeup_interval)
			cond_resched();
#endif
	} while (ktime_before(end_time, timeout) && !break_test());
	trace_printk("End ring buffer hammer\n");

	if (consumer) {
		/* Init both completions here to avoid races */
		init_completion(&read_start);
		init_completion(&read_done);
		/* the completions must be visible before the finish var */
		smp_wmb();
		reader_finish = 1;
		wake_up_process(consumer);
		wait_for_completion(&read_done);
	}

	time = ktime_us_delta(end_time, start_time);

	entries = ring_buffer_entries(buffer);
	overruns = ring_buffer_overruns(buffer);

	if (test_error)
		trace_printk("ERROR!\n");

	if (!disable_reader) {
		if (consumer_fifo < 0)
			trace_printk("Running Consumer at nice: %d\n",
				     consumer_nice);
		else
			trace_printk("Running Consumer at SCHED_FIFO %d\n",
				     consumer_fifo);
	}
	if (producer_fifo < 0)
		trace_printk("Running Producer at nice: %d\n",
			     producer_nice);
	else
		trace_printk("Running Producer at SCHED_FIFO %d\n",
			     producer_fifo);

	/* Let the user know that the test is running at low priority */
	if (producer_fifo < 0 && consumer_fifo < 0 &&
	    producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
		trace_printk("WARNING!!! This test is running at lowest priority.\n");

	trace_printk("Time:     %lld (usecs)\n", time);
	trace_printk("Overruns: %lld\n", overruns);
	if (disable_reader)
		trace_printk("Read:     (reader disabled)\n");
	else
		trace_printk("Read:     %ld  (by %s)\n", read,
			read_events ? "events" : "pages");
	trace_printk("Entries:  %lld\n", entries);
	trace_printk("Total:    %lld\n", entries + overruns + read);
	trace_printk("Missed:   %ld\n", missed);
	trace_printk("Hit:      %ld\n", hit);

	/* Convert time from usecs to millisecs */
	do_div(time, USEC_PER_MSEC);
	if (time)
		hit /= (long)time;
	else
		trace_printk("TIME IS ZERO??\n");

	trace_printk("Entries per millisec: %ld\n", hit);

	if (hit) {
		/* Calculate the average time in nanosecs */
		avg = NSEC_PER_MSEC / hit;
		trace_printk("%ld ns per entry\n", avg);
	}

	if (missed) {
		if (time)
			missed /= (long)time;

		trace_printk("Total iterations per millisec: %ld\n",
			     hit + missed);

		/* it is possible that hit + missed will overflow and be zero */
		if (!(hit + missed)) {
			trace_printk("hit + missed overflowed and totalled zero!\n");
			hit--; /* make it non zero */
		}

		/* Caculate the average time in nanosecs */
		avg = NSEC_PER_MSEC / (hit + missed);
		trace_printk("%ld ns per entry\n", avg);
	}
}

static void wait_to_die(void)
{
	set_current_state(TASK_INTERRUPTIBLE);
	while (!kthread_should_stop()) {
		schedule();
		set_current_state(TASK_INTERRUPTIBLE);
	}
	__set_current_state(TASK_RUNNING);
}

static int ring_buffer_consumer_thread(void *arg)
{
	while (!break_test()) {
		complete(&read_start);

		ring_buffer_consumer();

		set_current_state(TASK_INTERRUPTIBLE);
		if (break_test())
			break;
		schedule();
	}
	__set_current_state(TASK_RUNNING);

	if (!kthread_should_stop())
		wait_to_die();

	return 0;
}

static int ring_buffer_producer_thread(void *arg)
{
	while (!break_test()) {
		ring_buffer_reset(buffer);

		if (consumer) {
			wake_up_process(consumer);
			wait_for_completion(&read_start);
		}

		ring_buffer_producer();
		if (break_test())
			goto out_kill;

		trace_printk("Sleeping for 10 secs\n");
		set_current_state(TASK_INTERRUPTIBLE);
		if (break_test())
			goto out_kill;
		schedule_timeout(HZ * SLEEP_TIME);
	}

out_kill:
	__set_current_state(TASK_RUNNING);
	if (!kthread_should_stop())
		wait_to_die();

	return 0;
}

static int __init ring_buffer_benchmark_init(void)
{
	int ret;

	/* make a one meg buffer in overwite mode */
	buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
	if (!buffer)
		return -ENOMEM;

	if (!disable_reader) {
		consumer = kthread_create(ring_buffer_consumer_thread,
					  NULL, "rb_consumer");
		ret = PTR_ERR(consumer);
		if (IS_ERR(consumer))
			goto out_fail;
	}

	producer = kthread_run(ring_buffer_producer_thread,
			       NULL, "rb_producer");
	ret = PTR_ERR(producer);

	if (IS_ERR(producer))
		goto out_kill;

	/*
	 * Run them as low-prio background tasks by default:
	 */
	if (!disable_reader) {
		if (consumer_fifo >= 0) {
			struct sched_param param = {
				.sched_priority = consumer_fifo
			};
			sched_setscheduler(consumer, SCHED_FIFO, &param);
		} else
			set_user_nice(consumer, consumer_nice);
	}

	if (producer_fifo >= 0) {
		struct sched_param param = {
			.sched_priority = producer_fifo
		};
		sched_setscheduler(producer, SCHED_FIFO, &param);
	} else
		set_user_nice(producer, producer_nice);

	return 0;

 out_kill:
	if (consumer)
		kthread_stop(consumer);

 out_fail:
	ring_buffer_free(buffer);
	return ret;
}

static void __exit ring_buffer_benchmark_exit(void)
{
	kthread_stop(producer);
	if (consumer)
		kthread_stop(consumer);
	ring_buffer_free(buffer);
}

module_init(ring_buffer_benchmark_init);
module_exit(ring_buffer_benchmark_exit);

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