[mirror_ubuntu-zesty-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 <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 struct completion read_start;
static struct 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 kill_test;

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

enum event_status {
	EVENT_FOUND,
	EVENT_DROPPED,
};

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) {
		KILL_TEST();
		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 && !kill_test; i += inc) {

			if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
				KILL_TEST();
				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)
					KILL_TEST();
				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) {
					KILL_TEST();
					break;
				}
				read++;
				if (!event->array[0]) {
					KILL_TEST();
					break;
				}
				inc = event->array[0] + 4;
				break;
			default:
				entry = ring_buffer_event_data(event);
				if (*entry != cpu) {
					KILL_TEST();
					break;
				}
				read++;
				inc = ((event->type_len + 1) * 4);
			}
			if (kill_test)
				break;

			if (inc <= 0) {
				KILL_TEST();
				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;
	while (!reader_finish && !kill_test) {
		int found;

		do {
			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 (kill_test)
					break;
				if (stat == EVENT_FOUND)
					found = 1;
			}
		} while (found && !kill_test);

		set_current_state(TASK_INTERRUPTIBLE);
		if (reader_finish)
			break;

		schedule();
	}
	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
		if (kthread_should_stop())
			kill_test = 1;

	} while (ktime_before(end_time, timeout) && !kill_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;
		/* finish var visible before waking up the consumer */
		smp_wmb();
		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 (kill_test && !kthread_should_stop())
		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 (!kthread_should_stop() && !kill_test) {
		complete(&read_start);

		ring_buffer_consumer();

		set_current_state(TASK_INTERRUPTIBLE);
		if (kthread_should_stop() || kill_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)
{
	init_completion(&read_start);

	while (!kthread_should_stop() && !kill_test) {
		ring_buffer_reset(buffer);

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

		ring_buffer_producer();
		if (kill_test)
			goto out_kill;

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

out_kill:
	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;
	27	static struct completion read_start;
	28	static struct completion read_done;
	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;
	62
	63	static int kill_test;
	64
	65	#define KILL_TEST() \
	66	do { \
	67	if (!kill_test) { \
	68	kill_test = 1; \
	69	WARN_ON(1); \
	70	} \
	71	} while (0)
	72
	73	enum event_status {
	74	EVENT_FOUND,
	75	EVENT_DROPPED,
	76	};
	77
	78	static enum event_status read_event(int cpu)
	79	{
	80	struct ring_buffer_event *event;
	81	int *entry;
	82	u64 ts;
	83
66a8cb95	84	event = ring_buffer_consume(buffer, cpu, &ts, NULL);
5092dbc9 SR	85	if (!event)
	86	return EVENT_DROPPED;
	87
	88	entry = ring_buffer_event_data(event);
	89	if (*entry != cpu) {
	90	KILL_TEST();
	91	return EVENT_DROPPED;
	92	}
	93
	94	read++;
	95	return EVENT_FOUND;
	96	}
	97
	98	static enum event_status read_page(int cpu)
	99	{
	100	struct ring_buffer_event *event;
	101	struct rb_page *rpage;
	102	unsigned long commit;
	103	void *bpage;
	104	int *entry;
	105	int ret;
	106	int inc;
	107	int i;
	108
7ea59064	109	bpage = ring_buffer_alloc_read_page(buffer, cpu);
00c81a58 SR	110	if (!bpage)
	111	return EVENT_DROPPED;
	112
5092dbc9 SR	113	ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
	114	if (ret >= 0) {
	115	rpage = bpage;
a838b2e6 SR	116	/* The commit may have missed event flags set, clear them */
a838b2e6 SR	117	commit = local_read(&rpage->commit) & 0xfffff;
5092dbc9 SR	118	for (i = 0; i < commit && !kill_test; i += inc) {
	119
	120	if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
	121	KILL_TEST();
	122	break;
	123	}
	124
	125	inc = -1;
	126	event = (void *)&rpage->data[i];
	127	switch (event->type_len) {
	128	case RINGBUF_TYPE_PADDING:
9086c7b9 SR	129	/* failed writes may be discarded events */
	130	if (!event->time_delta)
	131	KILL_TEST();
	132	inc = event->array[0] + 4;
5092dbc9 SR	133	break;
	134	case RINGBUF_TYPE_TIME_EXTEND:
	135	inc = 8;
	136	break;
	137	case 0:
	138	entry = ring_buffer_event_data(event);
	139	if (*entry != cpu) {
	140	KILL_TEST();
	141	break;
	142	}
	143	read++;
	144	if (!event->array[0]) {
	145	KILL_TEST();
	146	break;
	147	}
9086c7b9	148	inc = event->array[0] + 4;
5092dbc9 SR	149	break;
	150	default:
	151	entry = ring_buffer_event_data(event);
	152	if (*entry != cpu) {
	153	KILL_TEST();
	154	break;
	155	}
	156	read++;
	157	inc = ((event->type_len + 1) * 4);
	158	}
	159	if (kill_test)
	160	break;
	161
	162	if (inc <= 0) {
	163	KILL_TEST();
	164	break;
	165	}
	166	}
	167	}
	168	ring_buffer_free_read_page(buffer, bpage);
	169
	170	if (ret < 0)
	171	return EVENT_DROPPED;
	172	return EVENT_FOUND;
	173	}
	174
	175	static void ring_buffer_consumer(void)
	176	{
	177	/* toggle between reading pages and events */
	178	read_events ^= 1;
	179
	180	read = 0;
	181	while (!reader_finish && !kill_test) {
	182	int found;
	183
	184	do {
	185	int cpu;
	186
	187	found = 0;
	188	for_each_online_cpu(cpu) {
	189	enum event_status stat;
	190
	191	if (read_events)
	192	stat = read_event(cpu);
	193	else
	194	stat = read_page(cpu);
	195
	196	if (kill_test)
	197	break;
	198	if (stat == EVENT_FOUND)
	199	found = 1;
	200	}
	201	} while (found && !kill_test);
	202
	203	set_current_state(TASK_INTERRUPTIBLE);
	204	if (reader_finish)
	205	break;
	206
	207	schedule();
5092dbc9 SR	208	}
	209	reader_finish = 0;
	210	complete(&read_done);
	211	}
	212
	213	static void ring_buffer_producer(void)
	214	{
da194930	215	ktime_t start_time, end_time, timeout;
5092dbc9 SR	216	unsigned long long time;
	217	unsigned long long entries;
	218	unsigned long long overruns;
	219	unsigned long missed = 0;
	220	unsigned long hit = 0;
	221	unsigned long avg;
	222	int cnt = 0;
	223
	224	/*
	225	* Hammer the buffer for 10 secs (this may
	226	* make the system stall)
	227	*/
4b221f03	228	trace_printk("Starting ring buffer hammer\n");
da194930 TR	229	start_time = ktime_get();
da194930 TR	230	timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
5092dbc9 SR	231	do {
	232	struct ring_buffer_event *event;
	233	int *entry;
a6f0eb6a SR	234	int i;
	235
	236	for (i = 0; i < write_iteration; i++) {
	237	event = ring_buffer_lock_reserve(buffer, 10);
	238	if (!event) {
	239	missed++;
	240	} else {
	241	hit++;
	242	entry = ring_buffer_event_data(event);
	243	*entry = smp_processor_id();
	244	ring_buffer_unlock_commit(buffer, event);
	245	}
5092dbc9	246	}
da194930	247	end_time = ktime_get();
5092dbc9	248
0574ea42 SR	249	cnt++;
0574ea42 SR	250	if (consumer && !(cnt % wakeup_interval))
5092dbc9 SR	251	wake_up_process(consumer);
5092dbc9 SR	252
0574ea42	253	#ifndef CONFIG_PREEMPT
29c8000e SR	254	/*
	255	* If we are a non preempt kernel, the 10 second run will
	256	* stop everything while it runs. Instead, we will call
	257	* cond_resched and also add any time that was lost by a
	258	* rescedule.
0574ea42 SR	259	*
	260	* Do a cond resched at the same frequency we would wake up
	261	* the reader.
29c8000e	262	*/
0574ea42 SR	263	if (cnt % wakeup_interval)
	264	cond_resched();
	265	#endif
b44754d8 PM	266	if (kthread_should_stop())
b44754d8 PM	267	kill_test = 1;
3e07a4f6	268
da194930	269	} while (ktime_before(end_time, timeout) && !kill_test);
4b221f03	270	trace_printk("End ring buffer hammer\n");
5092dbc9 SR	271
	272	if (consumer) {
	273	/* Init both completions here to avoid races */
	274	init_completion(&read_start);
	275	init_completion(&read_done);
	276	/* the completions must be visible before the finish var */
	277	smp_wmb();
	278	reader_finish = 1;
	279	/* finish var visible before waking up the consumer */
	280	smp_wmb();
	281	wake_up_process(consumer);
	282	wait_for_completion(&read_done);
	283	}
	284
da194930	285	time = ktime_us_delta(end_time, start_time);
5092dbc9 SR	286
	287	entries = ring_buffer_entries(buffer);
	288	overruns = ring_buffer_overruns(buffer);
	289
b44754d8	290	if (kill_test && !kthread_should_stop())
4b221f03	291	trace_printk("ERROR!\n");
7ac07434 SR	292
	293	if (!disable_reader) {
	294	if (consumer_fifo < 0)
	295	trace_printk("Running Consumer at nice: %d\n",
	296	consumer_nice);
	297	else
	298	trace_printk("Running Consumer at SCHED_FIFO %d\n",
	299	consumer_fifo);
	300	}
	301	if (producer_fifo < 0)
	302	trace_printk("Running Producer at nice: %d\n",
	303	producer_nice);
	304	else
	305	trace_printk("Running Producer at SCHED_FIFO %d\n",
	306	producer_fifo);
	307
	308	/* Let the user know that the test is running at low priority */
	309	if (producer_fifo < 0 && consumer_fifo < 0 &&
2b3942e4	310	producer_nice == MAX_NICE && consumer_nice == MAX_NICE)
7ac07434 SR	311	trace_printk("WARNING!!! This test is running at lowest priority.\n");
7ac07434 SR	312
4b221f03 SR	313	trace_printk("Time: %lld (usecs)\n", time);
4b221f03 SR	314	trace_printk("Overruns: %lld\n", overruns);
5092dbc9	315	if (disable_reader)
4b221f03	316	trace_printk("Read: (reader disabled)\n");
5092dbc9	317	else
4b221f03	318	trace_printk("Read: %ld (by %s)\n", read,
5092dbc9	319	read_events ? "events" : "pages");
4b221f03 SR	320	trace_printk("Entries: %lld\n", entries);
	321	trace_printk("Total: %lld\n", entries + overruns + read);
	322	trace_printk("Missed: %ld\n", missed);
	323	trace_printk("Hit: %ld\n", hit);
5092dbc9	324
5a772b2b SR	325	/* Convert time from usecs to millisecs */
5a772b2b SR	326	do_div(time, USEC_PER_MSEC);
5092dbc9 SR	327	if (time)
	328	hit /= (long)time;
	329	else
4b221f03	330	trace_printk("TIME IS ZERO??\n");
5092dbc9	331
4b221f03	332	trace_printk("Entries per millisec: %ld\n", hit);
5092dbc9 SR	333
5092dbc9 SR	334	if (hit) {
5a772b2b SR	335	/* Calculate the average time in nanosecs */
5a772b2b SR	336	avg = NSEC_PER_MSEC / hit;
4b221f03	337	trace_printk("%ld ns per entry\n", avg);
5092dbc9	338	}
7da3046d	339
7da3046d SR	340	if (missed) {
	341	if (time)
	342	missed /= (long)time;
	343
4b221f03 SR	344	trace_printk("Total iterations per millisec: %ld\n",
4b221f03 SR	345	hit + missed);
7da3046d	346
d988ff94 SR	347	/* it is possible that hit + missed will overflow and be zero */
d988ff94 SR	348	if (!(hit + missed)) {
4b221f03	349	trace_printk("hit + missed overflowed and totalled zero!\n");
d988ff94 SR	350	hit--; /* make it non zero */
	351	}
	352
5a772b2b SR	353	/* Caculate the average time in nanosecs */
5a772b2b SR	354	avg = NSEC_PER_MSEC / (hit + missed);
4b221f03	355	trace_printk("%ld ns per entry\n", avg);
7da3046d	356	}
5092dbc9 SR	357	}
	358
	359	static void wait_to_die(void)
	360	{
	361	set_current_state(TASK_INTERRUPTIBLE);
	362	while (!kthread_should_stop()) {
	363	schedule();
	364	set_current_state(TASK_INTERRUPTIBLE);
	365	}
	366	__set_current_state(TASK_RUNNING);
	367	}
	368
	369	static int ring_buffer_consumer_thread(void *arg)
	370	{
	371	while (!kthread_should_stop() && !kill_test) {
	372	complete(&read_start);
	373
	374	ring_buffer_consumer();
	375
	376	set_current_state(TASK_INTERRUPTIBLE);
	377	if (kthread_should_stop() \|\| kill_test)
	378	break;
	379
	380	schedule();
5092dbc9 SR	381	}
	382	__set_current_state(TASK_RUNNING);
	383
b44754d8	384	if (!kthread_should_stop())
5092dbc9 SR	385	wait_to_die();
	386
	387	return 0;
	388	}
	389
	390	static int ring_buffer_producer_thread(void *arg)
	391	{
	392	init_completion(&read_start);
	393
	394	while (!kthread_should_stop() && !kill_test) {
	395	ring_buffer_reset(buffer);
	396
	397	if (consumer) {
	398	smp_wmb();
	399	wake_up_process(consumer);
	400	wait_for_completion(&read_start);
	401	}
	402
	403	ring_buffer_producer();
b44754d8 PM	404	if (kill_test)
b44754d8 PM	405	goto out_kill;
5092dbc9	406
4b221f03	407	trace_printk("Sleeping for 10 secs\n");
5092dbc9 SR	408	set_current_state(TASK_INTERRUPTIBLE);
5092dbc9 SR	409	schedule_timeout(HZ * SLEEP_TIME);
5092dbc9 SR	410	}
5092dbc9 SR	411
b44754d8 PM	412	out_kill:
b44754d8 PM	413	if (!kthread_should_stop())
5092dbc9 SR	414	wait_to_die();
	415
	416	return 0;
	417	}
	418
	419	static int __init ring_buffer_benchmark_init(void)
	420	{
	421	int ret;
	422
	423	/* make a one meg buffer in overwite mode */
	424	buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
	425	if (!buffer)
	426	return -ENOMEM;
	427
	428	if (!disable_reader) {
	429	consumer = kthread_create(ring_buffer_consumer_thread,
	430	NULL, "rb_consumer");
	431	ret = PTR_ERR(consumer);
	432	if (IS_ERR(consumer))
	433	goto out_fail;
	434	}
	435
	436	producer = kthread_run(ring_buffer_producer_thread,
	437	NULL, "rb_producer");
	438	ret = PTR_ERR(producer);
	439
	440	if (IS_ERR(producer))
	441	goto out_kill;
	442
98e4833b IM	443	/*
	444	* Run them as low-prio background tasks by default:
	445	*/
7ac07434 SR	446	if (!disable_reader) {
	447	if (consumer_fifo >= 0) {
	448	struct sched_param param = {
	449	.sched_priority = consumer_fifo
	450	};
	451	sched_setscheduler(consumer, SCHED_FIFO, &param);
	452	} else
	453	set_user_nice(consumer, consumer_nice);
	454	}
	455
	456	if (producer_fifo >= 0) {
	457	struct sched_param param = {
10802932	458	.sched_priority = producer_fifo
7ac07434 SR	459	};
	460	sched_setscheduler(producer, SCHED_FIFO, &param);
	461	} else
	462	set_user_nice(producer, producer_nice);
98e4833b	463
5092dbc9 SR	464	return 0;
	465
	466	out_kill:
	467	if (consumer)
	468	kthread_stop(consumer);
	469
	470	out_fail:
	471	ring_buffer_free(buffer);
	472	return ret;
	473	}
	474
	475	static void __exit ring_buffer_benchmark_exit(void)
	476	{
	477	kthread_stop(producer);
	478	if (consumer)
	479	kthread_stop(consumer);
	480	ring_buffer_free(buffer);
	481	}
	482
	483	module_init(ring_buffer_benchmark_init);
	484	module_exit(ring_buffer_benchmark_exit);
	485
	486	MODULE_AUTHOR("Steven Rostedt");
	487	MODULE_DESCRIPTION("ring_buffer_benchmark");
	488	MODULE_LICENSE("GPL");