[lttv.git] / trunk / tests / kernel / test-fair-rwlock.c

/* test-fair-rwlock.c
 *
 */

#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/timex.h>
#include <linux/fair-rwlock.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <asm/ptrace.h>

#if (NR_CPUS > 64 && (BITS_PER_LONG == 32 || NR_CPUS > 32768))
#error "fair rwlock needs more bits per long to deal with that many CPUs"
#endif

#define THREAD_ROFFSET	1UL
#define THREAD_RMASK	((NR_CPUS - 1) * THREAD_ROFFSET)
#define SOFTIRQ_ROFFSET	(THREAD_RMASK + 1)
#define SOFTIRQ_RMASK	((NR_CPUS - 1) * SOFTIRQ_ROFFSET)
#define HARDIRQ_ROFFSET	((SOFTIRQ_RMASK | THREAD_RMASK) + 1)
#define HARDIRQ_RMASK	((NR_CPUS - 1) * HARDIRQ_ROFFSET)

#define SUBSCRIBERS_WOFFSET	\
	((HARDIRQ_RMASK | SOFTIRQ_RMASK | THREAD_RMASK) + 1)
#define SUBSCRIBERS_WMASK	\
	((NR_CPUS - 1) * SUBSCRIBERS_WOFFSET)
#define WRITER_MUTEX		\
	((SUBSCRIBERS_WMASK | HARDIRQ_RMASK | SOFTIRQ_RMASK | THREAD_RMASK) + 1)
#define SOFTIRQ_WMASK	(WRITER_MUTEX << 1)
#define SOFTIRQ_WOFFSET	SOFTIRQ_WMASK
#define HARDIRQ_WMASK	(SOFTIRQ_WMASK << 1)
#define HARDIRQ_WOFFSET	HARDIRQ_WMASK

#define NR_VARS 100
#define NR_WRITERS 3
#define NR_READERS 6
#define NR_INTERRUPT_READERS 2

static int var[NR_VARS];
static struct task_struct *reader_threads[NR_READERS];
static struct task_struct *writer_threads[NR_WRITERS];
static struct task_struct *interrupt_reader;

static struct fair_rwlock frwlock = {
	.value = ATOMIC_LONG_INIT(0),
};

struct proc_dir_entry *pentry = NULL;

static int reader_thread(void *data)
{
	int i;
	int prev, cur;
	unsigned long iter = 0;
	cycles_t time1, time2, delaymax = 0;

	printk("reader_thread/%lu runnning\n", (unsigned long)data);
	do {
		iter++;
		preempt_disable();	/* for get_cycles accuracy */
		time1 = get_cycles();
		fair_read_lock(&frwlock);
		time2 = get_cycles();
		delaymax = max(delaymax, time2 - time1);
		prev = var[0];
		for (i = 1; i < NR_VARS; i++) {
			cur = var[i];
			if (cur != prev)
				printk(KERN_ALERT
				"Unequal cur %d/prev %d at i %d, iter %lu "
				"in thread\n", cur, prev, i, iter);
		}
		fair_read_unlock(&frwlock);
		preempt_enable();	/* for get_cycles accuracy */
		//msleep(100);
	} while (!kthread_should_stop());
	printk("reader_thread/%lu iterations : %lu, "
		"max contention %llu cycles\n",
		(unsigned long)data, iter, delaymax);
	return 0;
}

DEFINE_PER_CPU(cycles_t, int_delaymax);

static void interrupt_reader_ipi(void *data)
{
	int i;
	int prev, cur;
	cycles_t time1, time2;
	cycles_t *delaymax;

	/*
	 * Skip the ipi caller, not in irq context.
	 */
	if (!in_irq())
		return;

	delaymax = &per_cpu(int_delaymax, smp_processor_id());
	time1 = get_cycles();
	fair_read_lock(&frwlock);
	time2 = get_cycles();
	*delaymax = max(*delaymax, time2 - time1);
	prev = var[0];
	for (i = 1; i < NR_VARS; i++) {
		cur = var[i];
		if (cur != prev)
			printk(KERN_ALERT
			"Unequal cur %d/prev %d at i %d in interrupt\n",
				cur, prev, i);
	}
	fair_read_unlock(&frwlock);
}

static int interrupt_reader_thread(void *data)
{
	unsigned long iter = 0;
	int i;

	do {
		iter++;
		on_each_cpu(interrupt_reader_ipi, NULL, 0);
		msleep(100);
	} while (!kthread_should_stop());
	printk("interrupt_reader_thread/%lu iterations : %lu\n",
			(unsigned long)data, iter);
	for_each_online_cpu(i) {
		printk("interrupt readers on CPU %i, "
			"max contention : %llu cycles\n",
			i, per_cpu(int_delaymax, i));
	}
	return 0;
}

static int writer_thread(void *data)
{
	int i;
	int new;
	unsigned long iter = 0;
	cycles_t time1, time2, delaymax = 0;

	printk("writer_thread/%lu runnning\n", (unsigned long)data);
	do {
		iter++;
		preempt_disable();	/* for get_cycles accuracy */
		time1 = get_cycles();
		fair_write_lock_irq(&frwlock);
		//fair_write_lock(&frwlock);
		time2 = get_cycles();
		delaymax = max(delaymax, time2 - time1);
		new = (int)get_cycles();
		for (i = 0; i < NR_VARS; i++) {
			var[i] = new;
		}
		//fair_write_unlock(&frwlock);
		fair_write_unlock_irq(&frwlock);
		preempt_enable();	/* for get_cycles accuracy */
		//msleep(100);
	} while (!kthread_should_stop());
	printk("writer_thread/%lu iterations : %lu, "
		"max contention %llu cycles\n",
		(unsigned long)data, iter, delaymax);
	return 0;
}

static void fair_rwlock_create(void)
{
	unsigned long i;

	for (i = 0; i < NR_READERS; i++) {
		printk("starting reader thread %lu\n", i);
		reader_threads[i] = kthread_run(reader_thread, (void *)i,
			"frwlock_reader");
		BUG_ON(!reader_threads[i]);
	}

	printk("starting interrupt reader %lu\n", i);
	interrupt_reader = kthread_run(interrupt_reader_thread, NULL,
		"frwlock_interrupt_reader");

	for (i = 0; i < NR_WRITERS; i++) {
		printk("starting writer thread %lu\n", i);
		writer_threads[i] = kthread_run(writer_thread, (void *)i,
			"frwlock_writer");
		BUG_ON(!writer_threads[i]);
	}
}

static void fair_rwlock_stop(void)
{
	unsigned long i;

	for (i = 0; i < NR_WRITERS; i++) {
		kthread_stop(writer_threads[i]);
	}

	for (i = 0; i < NR_READERS; i++) {
		kthread_stop(reader_threads[i]);
	}

	kthread_stop(interrupt_reader);
}


static void perform_test(const char *name, void (*callback)(void))
{
	printk("%s\n", name);
	callback();
}

static int my_open(struct inode *inode, struct file *file)
{
	perform_test("fair-rwlock-create", fair_rwlock_create);
	ssleep(30);
	perform_test("fair-rwlock-stop", fair_rwlock_stop);

	return -EPERM;
}


static struct file_operations my_operations = {
	.open = my_open,
};

int init_module(void)
{
	pentry = create_proc_entry("testfrwlock", 0444, NULL);
	if (pentry)
		pentry->proc_fops = &my_operations;

	printk("NR_CPUS : %d\n", NR_CPUS);
	printk("THREAD_ROFFSET : %lX\n", THREAD_ROFFSET);
	printk("THREAD_RMASK : %lX\n", THREAD_RMASK);
	printk("SOFTIRQ_ROFFSET : %lX\n", SOFTIRQ_ROFFSET);
	printk("SOFTIRQ_RMASK : %lX\n", SOFTIRQ_RMASK);
	printk("HARDIRQ_ROFFSET : %lX\n", HARDIRQ_ROFFSET);
	printk("HARDIRQ_RMASK : %lX\n", HARDIRQ_RMASK);
	printk("SUBSCRIBERS_WOFFSET : %lX\n", SUBSCRIBERS_WOFFSET);
	printk("SUBSCRIBERS_WMASK : %lX\n", SUBSCRIBERS_WMASK);
	printk("WRITER_MUTEX : %lX\n", WRITER_MUTEX);
	printk("SOFTIRQ_WMASK : %lX\n", SOFTIRQ_WMASK);
	printk("HARDIRQ_WMASK : %lX\n", HARDIRQ_WMASK);

	return 0;
}

void cleanup_module(void)
{
	remove_proc_entry("testfrwlock", NULL);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Fair rwlock test");
Commit	Line	Data
f0a36bb1	1	/* test-fair-rwlock.c
	2	*
	3	*/
	4
	5	#include <linux/module.h>
	6	#include <linux/proc_fs.h>
	7	#include <linux/sched.h>
	8	#include <linux/timex.h>
	9	#include <linux/fair-rwlock.h>
	10	#include <linux/kthread.h>
	11	#include <linux/delay.h>
	12	#include <linux/hardirq.h>
	13	#include <linux/module.h>
7f563886	14	#include <linux/percpu.h>
f0a36bb1	15	#include <asm/ptrace.h>
f0a36bb1	16
7f563886	17	#if (NR_CPUS > 64 && (BITS_PER_LONG == 32 \|\| NR_CPUS > 32768))
f0a36bb1	18	#error "fair rwlock needs more bits per long to deal with that many CPUs"
	19	#endif
	20
	21	#define THREAD_ROFFSET 1UL
	22	#define THREAD_RMASK ((NR_CPUS - 1) * THREAD_ROFFSET)
	23	#define SOFTIRQ_ROFFSET (THREAD_RMASK + 1)
	24	#define SOFTIRQ_RMASK ((NR_CPUS - 1) * SOFTIRQ_ROFFSET)
	25	#define HARDIRQ_ROFFSET ((SOFTIRQ_RMASK \| THREAD_RMASK) + 1)
	26	#define HARDIRQ_RMASK ((NR_CPUS - 1) * HARDIRQ_ROFFSET)
	27
7f563886	28	#define SUBSCRIBERS_WOFFSET \
	29	((HARDIRQ_RMASK \| SOFTIRQ_RMASK \| THREAD_RMASK) + 1)
	30	#define SUBSCRIBERS_WMASK \
	31	((NR_CPUS - 1) * SUBSCRIBERS_WOFFSET)
	32	#define WRITER_MUTEX \
	33	((SUBSCRIBERS_WMASK \| HARDIRQ_RMASK \| SOFTIRQ_RMASK \| THREAD_RMASK) + 1)
	34	#define SOFTIRQ_WMASK (WRITER_MUTEX << 1)
	35	#define SOFTIRQ_WOFFSET SOFTIRQ_WMASK
426d6b67	36	#define HARDIRQ_WMASK (SOFTIRQ_WMASK << 1)
7f563886	37	#define HARDIRQ_WOFFSET HARDIRQ_WMASK
f0a36bb1	38
	39	#define NR_VARS 100
	40	#define NR_WRITERS 3
	41	#define NR_READERS 6
	42	#define NR_INTERRUPT_READERS 2
	43
	44	static int var[NR_VARS];
	45	static struct task_struct *reader_threads[NR_READERS];
	46	static struct task_struct *writer_threads[NR_WRITERS];
	47	static struct task_struct *interrupt_reader;
	48
	49	static struct fair_rwlock frwlock = {
	50	.value = ATOMIC_LONG_INIT(0),
f0a36bb1	51	};
	52
	53	struct proc_dir_entry *pentry = NULL;
	54
	55	static int reader_thread(void *data)
	56	{
	57	int i;
	58	int prev, cur;
	59	unsigned long iter = 0;
7f563886	60	cycles_t time1, time2, delaymax = 0;
f0a36bb1	61
	62	printk("reader_thread/%lu runnning\n", (unsigned long)data);
	63	do {
	64	iter++;
7f563886	65	preempt_disable(); /* for get_cycles accuracy */
7f563886	66	time1 = get_cycles();
f0a36bb1	67	fair_read_lock(&frwlock);
7f563886	68	time2 = get_cycles();
7f563886	69	delaymax = max(delaymax, time2 - time1);
f0a36bb1	70	prev = var[0];
	71	for (i = 1; i < NR_VARS; i++) {
	72	cur = var[i];
	73	if (cur != prev)
	74	printk(KERN_ALERT
	75	"Unequal cur %d/prev %d at i %d, iter %lu "
	76	"in thread\n", cur, prev, i, iter);
	77	}
	78	fair_read_unlock(&frwlock);
7f563886	79	preempt_enable(); /* for get_cycles accuracy */
f0a36bb1	80	//msleep(100);
f0a36bb1	81	} while (!kthread_should_stop());
7f563886	82	printk("reader_thread/%lu iterations : %lu, "
	83	"max contention %llu cycles\n",
	84	(unsigned long)data, iter, delaymax);
f0a36bb1	85	return 0;
	86	}
	87
7f563886	88	DEFINE_PER_CPU(cycles_t, int_delaymax);
7f563886	89
f0a36bb1	90	static void interrupt_reader_ipi(void *data)
	91	{
	92	int i;
	93	int prev, cur;
7f563886	94	cycles_t time1, time2;
	95	cycles_t *delaymax;
	96
	97	/*
	98	* Skip the ipi caller, not in irq context.
	99	*/
	100	if (!in_irq())
	101	return;
f0a36bb1	102
7f563886	103	delaymax = &per_cpu(int_delaymax, smp_processor_id());
7f563886	104	time1 = get_cycles();
f0a36bb1	105	fair_read_lock(&frwlock);
7f563886	106	time2 = get_cycles();
7f563886	107	delaymax = max(delaymax, time2 - time1);
f0a36bb1	108	prev = var[0];
	109	for (i = 1; i < NR_VARS; i++) {
	110	cur = var[i];
	111	if (cur != prev)
	112	printk(KERN_ALERT
	113	"Unequal cur %d/prev %d at i %d in interrupt\n",
	114	cur, prev, i);
	115	}
	116	fair_read_unlock(&frwlock);
	117	}
	118
	119	static int interrupt_reader_thread(void *data)
	120	{
	121	unsigned long iter = 0;
7f563886	122	int i;
7f563886	123
f0a36bb1	124	do {
	125	iter++;
	126	on_each_cpu(interrupt_reader_ipi, NULL, 0);
	127	msleep(100);
	128	} while (!kthread_should_stop());
	129	printk("interrupt_reader_thread/%lu iterations : %lu\n",
	130	(unsigned long)data, iter);
7f563886	131	for_each_online_cpu(i) {
	132	printk("interrupt readers on CPU %i, "
	133	"max contention : %llu cycles\n",
	134	i, per_cpu(int_delaymax, i));
	135	}
f0a36bb1	136	return 0;
	137	}
	138
	139	static int writer_thread(void *data)
	140	{
	141	int i;
	142	int new;
	143	unsigned long iter = 0;
7f563886	144	cycles_t time1, time2, delaymax = 0;
f0a36bb1	145
	146	printk("writer_thread/%lu runnning\n", (unsigned long)data);
	147	do {
	148	iter++;
7f563886	149	preempt_disable(); /* for get_cycles accuracy */
7f563886	150	time1 = get_cycles();
f0a36bb1	151	fair_write_lock_irq(&frwlock);
f0a36bb1	152	//fair_write_lock(&frwlock);
7f563886	153	time2 = get_cycles();
7f563886	154	delaymax = max(delaymax, time2 - time1);
f0a36bb1	155	new = (int)get_cycles();
	156	for (i = 0; i < NR_VARS; i++) {
	157	var[i] = new;
	158	}
	159	//fair_write_unlock(&frwlock);
	160	fair_write_unlock_irq(&frwlock);
7f563886	161	preempt_enable(); /* for get_cycles accuracy */
f0a36bb1	162	//msleep(100);
f0a36bb1	163	} while (!kthread_should_stop());
7f563886	164	printk("writer_thread/%lu iterations : %lu, "
	165	"max contention %llu cycles\n",
	166	(unsigned long)data, iter, delaymax);
f0a36bb1	167	return 0;
	168	}
	169
	170	static void fair_rwlock_create(void)
	171	{
	172	unsigned long i;
	173
	174	for (i = 0; i < NR_READERS; i++) {
	175	printk("starting reader thread %lu\n", i);
	176	reader_threads[i] = kthread_run(reader_thread, (void *)i,
	177	"frwlock_reader");
	178	BUG_ON(!reader_threads[i]);
	179	}
	180
	181	printk("starting interrupt reader %lu\n", i);
	182	interrupt_reader = kthread_run(interrupt_reader_thread, NULL,
	183	"frwlock_interrupt_reader");
	184
	185	for (i = 0; i < NR_WRITERS; i++) {
	186	printk("starting writer thread %lu\n", i);
	187	writer_threads[i] = kthread_run(writer_thread, (void *)i,
	188	"frwlock_writer");
	189	BUG_ON(!writer_threads[i]);
	190	}
	191	}
	192
	193	static void fair_rwlock_stop(void)
	194	{
	195	unsigned long i;
	196
7f563886	197	for (i = 0; i < NR_WRITERS; i++) {
	198	kthread_stop(writer_threads[i]);
	199	}
	200
f0a36bb1	201	for (i = 0; i < NR_READERS; i++) {
	202	kthread_stop(reader_threads[i]);
	203	}
	204
7f563886	205	kthread_stop(interrupt_reader);
f0a36bb1	206	}
	207
	208
	209	static void perform_test(const char name, void (callback)(void))
	210	{
	211	printk("%s\n", name);
	212	callback();
	213	}
	214
	215	static int my_open(struct inode inode, struct file file)
	216	{
	217	perform_test("fair-rwlock-create", fair_rwlock_create);
	218	ssleep(30);
	219	perform_test("fair-rwlock-stop", fair_rwlock_stop);
	220
	221	return -EPERM;
	222	}
	223
	224
	225	static struct file_operations my_operations = {
	226	.open = my_open,
	227	};
	228
	229	int init_module(void)
	230	{
	231	pentry = create_proc_entry("testfrwlock", 0444, NULL);
	232	if (pentry)
	233	pentry->proc_fops = &my_operations;
	234
	235	printk("NR_CPUS : %d\n", NR_CPUS);
	236	printk("THREAD_ROFFSET : %lX\n", THREAD_ROFFSET);
	237	printk("THREAD_RMASK : %lX\n", THREAD_RMASK);
f0a36bb1	238	printk("SOFTIRQ_ROFFSET : %lX\n", SOFTIRQ_ROFFSET);
f0a36bb1	239	printk("SOFTIRQ_RMASK : %lX\n", SOFTIRQ_RMASK);
f0a36bb1	240	printk("HARDIRQ_ROFFSET : %lX\n", HARDIRQ_ROFFSET);
f0a36bb1	241	printk("HARDIRQ_RMASK : %lX\n", HARDIRQ_RMASK);
7f563886	242	printk("SUBSCRIBERS_WOFFSET : %lX\n", SUBSCRIBERS_WOFFSET);
	243	printk("SUBSCRIBERS_WMASK : %lX\n", SUBSCRIBERS_WMASK);
	244	printk("WRITER_MUTEX : %lX\n", WRITER_MUTEX);
	245	printk("SOFTIRQ_WMASK : %lX\n", SOFTIRQ_WMASK);
f0a36bb1	246	printk("HARDIRQ_WMASK : %lX\n", HARDIRQ_WMASK);
	247
	248	return 0;
	249	}
	250
	251	void cleanup_module(void)
	252	{
	253	remove_proc_entry("testfrwlock", NULL);
	254	}
	255
	256	MODULE_LICENSE("GPL");
	257	MODULE_AUTHOR("Mathieu Desnoyers");
	258	MODULE_DESCRIPTION("Fair rwlock test");