[linux.git] / kernel / trace / ring_buffer_benchmark.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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 trace_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_PREEMPTION
		/*
		 * If we are a non preempt kernel, the 10 seconds run will
		 * stop everything while it runs. Instead, we will call
		 * cond_resched and also add any time that was lost by a
		 * reschedule.
		 *
		 * 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 */
		}

		/* Calculate 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
bcea3f96	1	// SPDX-License-Identifier: GPL-2.0
5092dbc9 SR	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>
ae7e81c0	10	#include <uapi/linux/sched/types.h>
5092dbc9	11	#include <linux/module.h>
da194930	12	#include <linux/ktime.h>
79615760	13	#include <asm/local.h>
5092dbc9 SR	14
	15	struct rb_page {
	16	u64 ts;
	17	local_t commit;
	18	char data[4080];
	19	};
	20
	21	/* run time and sleep time in seconds */
da194930	22	#define RUN_TIME 10ULL
5092dbc9 SR	23	#define SLEEP_TIME 10
	24
	25	/* number of events for writer to wake up the reader */
	26	static int wakeup_interval = 100;
	27
	28	static int reader_finish;
8b46ff69 PM	29	static DECLARE_COMPLETION(read_start);
8b46ff69 PM	30	static DECLARE_COMPLETION(read_done);
5092dbc9	31
13292494	32	static struct trace_buffer *buffer;
5092dbc9 SR	33	static struct task_struct *producer;
	34	static struct task_struct *consumer;
	35	static unsigned long read;
	36
33d657d1	37	static unsigned int disable_reader;
5092dbc9 SR	38	module_param(disable_reader, uint, 0644);
	39	MODULE_PARM_DESC(disable_reader, "only run producer");
	40
33d657d1	41	static unsigned int write_iteration = 50;
a6f0eb6a SR	42	module_param(write_iteration, uint, 0644);
	43	MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
	44
2b3942e4 DY	45	static int producer_nice = MAX_NICE;
2b3942e4 DY	46	static int consumer_nice = MAX_NICE;
7ac07434 SR	47
	48	static int producer_fifo = -1;
	49	static int consumer_fifo = -1;
	50
7364e865	51	module_param(producer_nice, int, 0644);
7ac07434 SR	52	MODULE_PARM_DESC(producer_nice, "nice prio for producer");
7ac07434 SR	53
7364e865	54	module_param(consumer_nice, int, 0644);
7ac07434 SR	55	MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
7ac07434 SR	56
7364e865	57	module_param(producer_fifo, int, 0644);
7ac07434 SR	58	MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
7ac07434 SR	59
7364e865	60	module_param(consumer_fifo, int, 0644);
7ac07434 SR	61	MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
7ac07434 SR	62
5092dbc9 SR	63	static int read_events;
5092dbc9 SR	64
f47cb66d	65	static int test_error;
5092dbc9	66
f47cb66d	67	#define TEST_ERROR() \
5092dbc9	68	do { \
f47cb66d PM	69	if (!test_error) { \
f47cb66d PM	70	test_error = 1; \
5092dbc9 SR	71	WARN_ON(1); \
	72	} \
	73	} while (0)
	74
	75	enum event_status {
	76	EVENT_FOUND,
	77	EVENT_DROPPED,
	78	};
	79
f47cb66d PM	80	static bool break_test(void)
	81	{
	82	return test_error \|\| kthread_should_stop();
	83	}
	84
5092dbc9 SR	85	static enum event_status read_event(int cpu)
	86	{
	87	struct ring_buffer_event *event;
	88	int *entry;
	89	u64 ts;
	90
66a8cb95	91	event = ring_buffer_consume(buffer, cpu, &ts, NULL);
5092dbc9 SR	92	if (!event)
	93	return EVENT_DROPPED;
	94
	95	entry = ring_buffer_event_data(event);
	96	if (*entry != cpu) {
f47cb66d	97	TEST_ERROR();
5092dbc9 SR	98	return EVENT_DROPPED;
	99	}
	100
	101	read++;
	102	return EVENT_FOUND;
	103	}
	104
	105	static 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
7ea59064	116	bpage = ring_buffer_alloc_read_page(buffer, cpu);
a7e52ad7	117	if (IS_ERR(bpage))
00c81a58 SR	118	return EVENT_DROPPED;
00c81a58 SR	119
5092dbc9 SR	120	ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
	121	if (ret >= 0) {
	122	rpage = bpage;
a838b2e6 SR	123	/* The commit may have missed event flags set, clear them */
a838b2e6 SR	124	commit = local_read(&rpage->commit) & 0xfffff;
f47cb66d	125	for (i = 0; i < commit && !test_error ; i += inc) {
5092dbc9 SR	126
5092dbc9 SR	127	if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
f47cb66d	128	TEST_ERROR();
5092dbc9 SR	129	break;
	130	}
	131
	132	inc = -1;
	133	event = (void *)&rpage->data[i];
	134	switch (event->type_len) {
	135	case RINGBUF_TYPE_PADDING:
9086c7b9 SR	136	/* failed writes may be discarded events */
9086c7b9 SR	137	if (!event->time_delta)
f47cb66d	138	TEST_ERROR();
9086c7b9	139	inc = event->array[0] + 4;
5092dbc9 SR	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) {
f47cb66d	147	TEST_ERROR();
5092dbc9 SR	148	break;
	149	}
	150	read++;
	151	if (!event->array[0]) {
f47cb66d	152	TEST_ERROR();
5092dbc9 SR	153	break;
5092dbc9 SR	154	}
9086c7b9	155	inc = event->array[0] + 4;
5092dbc9 SR	156	break;
	157	default:
	158	entry = ring_buffer_event_data(event);
	159	if (*entry != cpu) {
f47cb66d	160	TEST_ERROR();
5092dbc9 SR	161	break;
	162	}
	163	read++;
	164	inc = ((event->type_len + 1) * 4);
	165	}
f47cb66d	166	if (test_error)
5092dbc9 SR	167	break;
	168
	169	if (inc <= 0) {
f47cb66d	170	TEST_ERROR();
5092dbc9 SR	171	break;
	172	}
	173	}
	174	}
73a757e6	175	ring_buffer_free_read_page(buffer, cpu, bpage);
5092dbc9 SR	176
	177	if (ret < 0)
	178	return EVENT_DROPPED;
	179	return EVENT_FOUND;
	180	}
	181
	182	static void ring_buffer_consumer(void)
	183	{
	184	/* toggle between reading pages and events */
	185	read_events ^= 1;
	186
	187	read = 0;
8b46ff69 PM	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;
5092dbc9	194
f47cb66d	195	while (found && !test_error) {
5092dbc9 SR	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
f47cb66d	207	if (test_error)
5092dbc9	208	break;
8b46ff69	209
5092dbc9 SR	210	if (stat == EVENT_FOUND)
5092dbc9 SR	211	found = 1;
8b46ff69	212
5092dbc9	213	}
8b46ff69	214	}
5092dbc9	215
8b46ff69 PM	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	*/
5092dbc9 SR	219	set_current_state(TASK_INTERRUPTIBLE);
	220	if (reader_finish)
	221	break;
	222
	223	schedule();
5092dbc9	224	}
8b46ff69	225	__set_current_state(TASK_RUNNING);
5092dbc9 SR	226	reader_finish = 0;
	227	complete(&read_done);
	228	}
	229
	230	static void ring_buffer_producer(void)
	231	{
da194930	232	ktime_t start_time, end_time, timeout;
5092dbc9 SR	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	*/
4b221f03	245	trace_printk("Starting ring buffer hammer\n");
da194930 TR	246	start_time = ktime_get();
da194930 TR	247	timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
5092dbc9 SR	248	do {
	249	struct ring_buffer_event *event;
	250	int *entry;
a6f0eb6a SR	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, event);
	262	}
5092dbc9	263	}
da194930	264	end_time = ktime_get();
5092dbc9	265
0574ea42 SR	266	cnt++;
0574ea42 SR	267	if (consumer && !(cnt % wakeup_interval))
5092dbc9 SR	268	wake_up_process(consumer);
5092dbc9 SR	269
30c93704	270	#ifndef CONFIG_PREEMPTION
29c8000e	271	/*
a82a4804	272	* If we are a non preempt kernel, the 10 seconds run will
29c8000e SR	273	* stop everything while it runs. Instead, we will call
29c8000e SR	274	* cond_resched and also add any time that was lost by a
a82a4804	275	* reschedule.
0574ea42 SR	276	*
	277	* Do a cond resched at the same frequency we would wake up
	278	* the reader.
29c8000e	279	*/
0574ea42 SR	280	if (cnt % wakeup_interval)
	281	cond_resched();
	282	#endif
f47cb66d	283	} while (ktime_before(end_time, timeout) && !break_test());
4b221f03	284	trace_printk("End ring buffer hammer\n");
5092dbc9 SR	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;
5092dbc9 SR	293	wake_up_process(consumer);
	294	wait_for_completion(&read_done);
	295	}
	296
da194930	297	time = ktime_us_delta(end_time, start_time);
5092dbc9 SR	298
	299	entries = ring_buffer_entries(buffer);
	300	overruns = ring_buffer_overruns(buffer);
	301
f47cb66d	302	if (test_error)
4b221f03	303	trace_printk("ERROR!\n");
7ac07434 SR	304
	305	if (!disable_reader) {
	306	if (consumer_fifo < 0)
	307	trace_printk("Running Consumer at nice: %d\n",
	308	consumer_nice);
	309	else
	310	trace_printk("Running Consumer at SCHED_FIFO %d\n",
	311	consumer_fifo);
	312	}
	313	if (producer_fifo < 0)
	314	trace_printk("Running Producer at nice: %d\n",
	315	producer_nice);
	316	else
	317	trace_printk("Running Producer at SCHED_FIFO %d\n",
	318	producer_fifo);
	319
	320	/* Let the user know that the test is running at low priority */
	321	if (producer_fifo < 0 && consumer_fifo < 0 &&
2b3942e4	322	producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
7ac07434 SR	323	trace_printk("WARNING!!! This test is running at lowest priority.\n");
7ac07434 SR	324
4b221f03 SR	325	trace_printk("Time: %lld (usecs)\n", time);
4b221f03 SR	326	trace_printk("Overruns: %lld\n", overruns);
5092dbc9	327	if (disable_reader)
4b221f03	328	trace_printk("Read: (reader disabled)\n");
5092dbc9	329	else
4b221f03	330	trace_printk("Read: %ld (by %s)\n", read,
5092dbc9	331	read_events ? "events" : "pages");
4b221f03 SR	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);
5092dbc9	336
5a772b2b SR	337	/* Convert time from usecs to millisecs */
5a772b2b SR	338	do_div(time, USEC_PER_MSEC);
5092dbc9 SR	339	if (time)
	340	hit /= (long)time;
	341	else
4b221f03	342	trace_printk("TIME IS ZERO??\n");
5092dbc9	343
4b221f03	344	trace_printk("Entries per millisec: %ld\n", hit);
5092dbc9 SR	345
5092dbc9 SR	346	if (hit) {
5a772b2b SR	347	/* Calculate the average time in nanosecs */
5a772b2b SR	348	avg = NSEC_PER_MSEC / hit;
4b221f03	349	trace_printk("%ld ns per entry\n", avg);
5092dbc9	350	}
7da3046d	351
7da3046d SR	352	if (missed) {
	353	if (time)
	354	missed /= (long)time;
	355
4b221f03 SR	356	trace_printk("Total iterations per millisec: %ld\n",
4b221f03 SR	357	hit + missed);
7da3046d	358
d988ff94 SR	359	/* it is possible that hit + missed will overflow and be zero */
d988ff94 SR	360	if (!(hit + missed)) {
4b221f03	361	trace_printk("hit + missed overflowed and totalled zero!\n");
d988ff94 SR	362	hit--; /* make it non zero */
	363	}
	364
5c173bed	365	/* Calculate the average time in nanosecs */
5a772b2b	366	avg = NSEC_PER_MSEC / (hit + missed);
4b221f03	367	trace_printk("%ld ns per entry\n", avg);
7da3046d	368	}
5092dbc9 SR	369	}
	370
	371	static 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
	381	static int ring_buffer_consumer_thread(void *arg)
	382	{
f47cb66d	383	while (!break_test()) {
5092dbc9 SR	384	complete(&read_start);
	385
	386	ring_buffer_consumer();
	387
	388	set_current_state(TASK_INTERRUPTIBLE);
f47cb66d	389	if (break_test())
5092dbc9	390	break;
5092dbc9	391	schedule();
5092dbc9 SR	392	}
	393	__set_current_state(TASK_RUNNING);
	394
b44754d8	395	if (!kthread_should_stop())
5092dbc9 SR	396	wait_to_die();
	397
	398	return 0;
	399	}
	400
	401	static int ring_buffer_producer_thread(void *arg)
	402	{
f47cb66d	403	while (!break_test()) {
5092dbc9 SR	404	ring_buffer_reset(buffer);
	405
	406	if (consumer) {
5092dbc9 SR	407	wake_up_process(consumer);
	408	wait_for_completion(&read_start);
	409	}
	410
	411	ring_buffer_producer();
f47cb66d	412	if (break_test())
b44754d8	413	goto out_kill;
5092dbc9	414
4b221f03	415	trace_printk("Sleeping for 10 secs\n");
5092dbc9	416	set_current_state(TASK_INTERRUPTIBLE);
f47cb66d PM	417	if (break_test())
f47cb66d PM	418	goto out_kill;
5092dbc9	419	schedule_timeout(HZ * SLEEP_TIME);
5092dbc9 SR	420	}
5092dbc9 SR	421
b44754d8	422	out_kill:
f47cb66d	423	__set_current_state(TASK_RUNNING);
b44754d8	424	if (!kthread_should_stop())
5092dbc9 SR	425	wait_to_die();
	426
	427	return 0;
	428	}
	429
	430	static 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
98e4833b IM	454	/*
	455	* Run them as low-prio background tasks by default:
	456	*/
7ac07434 SR	457	if (!disable_reader) {
	458	if (consumer_fifo >= 0) {
	459	struct sched_param param = {
	460	.sched_priority = consumer_fifo
	461	};
	462	sched_setscheduler(consumer, SCHED_FIFO, &param);
	463	} else
	464	set_user_nice(consumer, consumer_nice);
	465	}
	466
	467	if (producer_fifo >= 0) {
	468	struct sched_param param = {
10802932	469	.sched_priority = producer_fifo
7ac07434 SR	470	};
	471	sched_setscheduler(producer, SCHED_FIFO, &param);
	472	} else
	473	set_user_nice(producer, producer_nice);
98e4833b	474
5092dbc9 SR	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
	486	static 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
	494	module_init(ring_buffer_benchmark_init);
	495	module_exit(ring_buffer_benchmark_exit);
	496
	497	MODULE_AUTHOR("Steven Rostedt");
	498	MODULE_DESCRIPTION("ring_buffer_benchmark");
	499	MODULE_LICENSE("GPL");