[mirror_ubuntu-artful-kernel.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 <uapi/linux/sched/types.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 (IS_ERR(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, cpu, 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>
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);
8b46ff69 PM	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;
2b3942e4 DY	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");
7ac07434 SR	52
7364e865	53	module_param(consumer_nice, int, 0644);
7ac07434 SR	54	MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
7ac07434 SR	55
7364e865	56	module_param(producer_fifo, int, 0644);
7ac07434 SR	57	MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
7ac07434 SR	58
7364e865	59	module_param(consumer_fifo, int, 0644);
7ac07434 SR	60	MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
7ac07434 SR	61
5092dbc9 SR	62	static int read_events;
5092dbc9 SR	63
f47cb66d	64	static int test_error;
5092dbc9	65
f47cb66d	66	#define TEST_ERROR() \
5092dbc9	67	do { \
f47cb66d PM	68	if (!test_error) { \
f47cb66d PM	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;
00c81a58 SR	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 */
a838b2e6 SR	123	commit = local_read(&rpage->commit) & 0xfffff;
f47cb66d	124	for (i = 0; i < commit && !test_error ; i += inc) {
5092dbc9 SR	125
5092dbc9 SR	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 */
9086c7b9 SR	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;
5092dbc9 SR	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)
5092dbc9 SR	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();
da194930 TR	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++;
0574ea42 SR	266	if (consumer && !(cnt % wakeup_interval))
5092dbc9 SR	267	wake_up_process(consumer);
5092dbc9 SR	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");
7ac07434 SR	323
4b221f03 SR	324	trace_printk("Time: %lld (usecs)\n", time);
4b221f03 SR	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 */
5a772b2b SR	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
5092dbc9 SR	345	if (hit) {
5a772b2b SR	346	/* Calculate the average time in nanosecs */
5a772b2b SR	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",
4b221f03 SR	356	hit + missed);
7da3046d	357
d988ff94 SR	358	/* it is possible that hit + missed will overflow and be zero */
d988ff94 SR	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 */
5a772b2b SR	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())
f47cb66d PM	417	goto out_kill;
5092dbc9	418	schedule_timeout(HZ * SLEEP_TIME);
5092dbc9 SR	419	}
5092dbc9 SR	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, &param);
	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, &param);
	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");