[urcu.git] / tests / test_urcu.c

/*
 * test_urcu.c
 *
 * Userspace RCU library - test program
 *
 * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <assert.h>
#include <sys/syscall.h>
#include <sched.h>

#include <urcu/arch.h>

/* hardcoded number of CPUs */
#define NR_CPUS 16384

#if defined(_syscall0)
_syscall0(pid_t, gettid)
#elif defined(__NR_gettid)
static inline pid_t gettid(void)
{
	return syscall(__NR_gettid);
}
#else
#warning "use pid as tid"
static inline pid_t gettid(void)
{
	return getpid();
}
#endif

#ifndef DYNAMIC_LINK_TEST
#define _LGPL_SOURCE
#else
#define debug_yield_read()
#endif
#include <urcu.h>

struct test_array {
	int a;
};

static volatile int test_go, test_stop;

static unsigned long wdelay;

static struct test_array *test_rcu_pointer;

static unsigned long duration;

/* read-side C.S. duration, in loops */
static unsigned long rduration;

static inline void loop_sleep(unsigned long l)
{
	while(l-- != 0)
		cpu_relax();
}

static int verbose_mode;

#define printf_verbose(fmt, args...)		\
	do {					\
		if (verbose_mode)		\
			printf(fmt, args);	\
	} while (0)

static unsigned int cpu_affinities[NR_CPUS];
static unsigned int next_aff = 0;
static int use_affinity = 0;

pthread_mutex_t affinity_mutex = PTHREAD_MUTEX_INITIALIZER;

static void set_affinity(void)
{
	cpu_set_t mask;
	int cpu;
	int ret;

	if (!use_affinity)
		return;

	ret = pthread_mutex_lock(&affinity_mutex);
	if (ret) {
		perror("Error in pthread mutex lock");
		exit(-1);
	}
	cpu = cpu_affinities[next_aff++];
	ret = pthread_mutex_unlock(&affinity_mutex);
	if (ret) {
		perror("Error in pthread mutex unlock");
		exit(-1);
	}
	CPU_ZERO(&mask);
	CPU_SET(cpu, &mask);
	sched_setaffinity(0, sizeof(mask), &mask);
}

/*
 * returns 0 if test should end.
 */
static int test_duration_write(void)
{
	return !test_stop;
}

static int test_duration_read(void)
{
	return !test_stop;
}

static unsigned long long __thread nr_writes;
static unsigned long long __thread nr_reads;

static unsigned int nr_readers;
static unsigned int nr_writers;

pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;

void rcu_copy_mutex_lock(void)
{
	int ret;
	ret = pthread_mutex_lock(&rcu_copy_mutex);
	if (ret) {
		perror("Error in pthread mutex lock");
		exit(-1);
	}
}

void rcu_copy_mutex_unlock(void)
{
	int ret;

	ret = pthread_mutex_unlock(&rcu_copy_mutex);
	if (ret) {
		perror("Error in pthread mutex unlock");
		exit(-1);
	}
}

/*
 * malloc/free are reusing memory areas too quickly, which does not let us
 * test races appropriately. Use a large circular array for allocations.
 * ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
 */
#define ARRAY_SIZE (1048576 * nr_writers)
#define ARRAY_POISON 0xDEADBEEF
static int array_index;
static struct test_array *test_array;

static struct test_array *test_array_alloc(void)
{
	struct test_array *ret;
	int index;

	rcu_copy_mutex_lock();
	index = array_index % ARRAY_SIZE;
	assert(test_array[index].a == ARRAY_POISON ||
		test_array[index].a == 0);
	ret = &test_array[index];
	array_index++;
	if (array_index == ARRAY_SIZE)
		array_index = 0;
	rcu_copy_mutex_unlock();
	return ret;
}

static void test_array_free(struct test_array *ptr)
{
	if (!ptr)
		return;
	rcu_copy_mutex_lock();
	ptr->a = ARRAY_POISON;
	rcu_copy_mutex_unlock();
}

void *thr_reader(void *_count)
{
	unsigned long long *count = _count;
	struct test_array *local_ptr;

	printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
			"reader", pthread_self(), (unsigned long)gettid());

	set_affinity();

	rcu_register_thread();

	while (!test_go)
	{
	}
	smp_mb();

	for (;;) {
		rcu_read_lock();
		local_ptr = rcu_dereference(test_rcu_pointer);
		debug_yield_read();
		if (local_ptr)
			assert(local_ptr->a == 8);
		if (unlikely(rduration))
			loop_sleep(rduration);
		rcu_read_unlock();
		nr_reads++;
		if (unlikely(!test_duration_read()))
			break;
	}

	rcu_unregister_thread();

	*count = nr_reads;
	printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
			"reader", pthread_self(), (unsigned long)gettid());
	return ((void*)1);

}

void *thr_writer(void *_count)
{
	unsigned long long *count = _count;
	struct test_array *new, *old;

	printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
			"writer", pthread_self(), (unsigned long)gettid());

	set_affinity();

	while (!test_go)
	{
	}
	smp_mb();

	for (;;) {
		new = test_array_alloc();
		new->a = 8;
		old = rcu_xchg_pointer(&test_rcu_pointer, new);
		synchronize_rcu();
		if (old)
			old->a = 0;
		test_array_free(old);
		nr_writes++;
		if (unlikely(!test_duration_write()))
			break;
		if (unlikely(wdelay))
			loop_sleep(wdelay);
	}

	printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
			"writer", pthread_self(), (unsigned long)gettid());
	*count = nr_writes;
	return ((void*)2);
}

void show_usage(int argc, char **argv)
{
	printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
#ifdef DEBUG_YIELD
	printf(" [-r] [-w] (yield reader and/or writer)");
#endif
	printf(" [-d delay] (writer period (us))");
	printf(" [-c duration] (reader C.S. duration (in loops))");
	printf(" [-v] (verbose output)");
	printf(" [-a cpu#] [-a cpu#]... (affinity)");
	printf("\n");
}

int main(int argc, char **argv)
{
	int err;
	pthread_t *tid_reader, *tid_writer;
	void *tret;
	unsigned long long *count_reader, *count_writer;
	unsigned long long tot_reads = 0, tot_writes = 0;
	int i, a;

	if (argc < 4) {
		show_usage(argc, argv);
		return -1;
	}

	err = sscanf(argv[1], "%u", &nr_readers);
	if (err != 1) {
		show_usage(argc, argv);
		return -1;
	}

	err = sscanf(argv[2], "%u", &nr_writers);
	if (err != 1) {
		show_usage(argc, argv);
		return -1;
	}
	
	err = sscanf(argv[3], "%lu", &duration);
	if (err != 1) {
		show_usage(argc, argv);
		return -1;
	}

	for (i = 4; i < argc; i++) {
		if (argv[i][0] != '-')
			continue;
		switch (argv[i][1]) {
#ifdef DEBUG_YIELD
		case 'r':
			yield_active |= YIELD_READ;
			break;
		case 'w':
			yield_active |= YIELD_WRITE;
			break;
#endif
		case 'a':
			if (argc < i + 2) {
				show_usage(argc, argv);
				return -1;
			}
			a = atoi(argv[++i]);
			cpu_affinities[next_aff++] = a;
			use_affinity = 1;
			printf_verbose("Adding CPU %d affinity\n", a);
			break;
		case 'c':
			if (argc < i + 2) {
				show_usage(argc, argv);
				return -1;
			}
			rduration = atol(argv[++i]);
			break;
		case 'd':
			if (argc < i + 2) {
				show_usage(argc, argv);
				return -1;
			}
			wdelay = atol(argv[++i]);
			break;
		case 'v':
			verbose_mode = 1;
			break;
		}
	}

	printf_verbose("running test for %lu seconds, %u readers, %u writers.\n",
		duration, nr_readers, nr_writers);
	printf_verbose("Writer delay : %lu loops.\n", wdelay);
	printf_verbose("Reader duration : %lu loops.\n", rduration);
	printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
			"main", pthread_self(), (unsigned long)gettid());

	test_array = malloc(sizeof(*test_array) * ARRAY_SIZE);
	tid_reader = malloc(sizeof(*tid_reader) * nr_readers);
	tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
	count_reader = malloc(sizeof(*count_reader) * nr_readers);
	count_writer = malloc(sizeof(*count_writer) * nr_writers);

	next_aff = 0;

	for (i = 0; i < nr_readers; i++) {
		err = pthread_create(&tid_reader[i], NULL, thr_reader,
				     &count_reader[i]);
		if (err != 0)
			exit(1);
	}
	for (i = 0; i < nr_writers; i++) {
		err = pthread_create(&tid_writer[i], NULL, thr_writer,
				     &count_writer[i]);
		if (err != 0)
			exit(1);
	}

	smp_mb();

	test_go = 1;

	sleep(duration);

	test_stop = 1;

	for (i = 0; i < nr_readers; i++) {
		err = pthread_join(tid_reader[i], &tret);
		if (err != 0)
			exit(1);
		tot_reads += count_reader[i];
	}
	for (i = 0; i < nr_writers; i++) {
		err = pthread_join(tid_writer[i], &tret);
		if (err != 0)
			exit(1);
		tot_writes += count_writer[i];
	}
	
	printf_verbose("total number of reads : %llu, writes %llu\n", tot_reads,
	       tot_writes);
	printf("SUMMARY %-25s testdur %4lu nr_readers %3u rdur %6lu "
		"nr_writers %3u "
		"wdelay %6lu nr_reads %12llu nr_writes %12llu nr_ops %12llu\n",
		argv[0], duration, nr_readers, rduration,
		nr_writers, wdelay, tot_reads, tot_writes,
		tot_reads + tot_writes);
	test_array_free(test_rcu_pointer);
	free(test_array);
	free(tid_reader);
	free(tid_writer);
	free(count_reader);
	free(count_writer);
	return 0;
}
Commit	Line	Data
	1	/*
	2	* test_urcu.c
	3	*
	4	* Userspace RCU library - test program
	5	*
	6	* Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License along
	19	* with this program; if not, write to the Free Software Foundation, Inc.,
	20	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	21	*/
	22
	23	#define _GNU_SOURCE
	24	#include <stdio.h>
	25	#include <pthread.h>
	26	#include <stdlib.h>
	27	#include <string.h>
	28	#include <sys/types.h>
	29	#include <sys/wait.h>
	30	#include <unistd.h>
	31	#include <stdio.h>
	32	#include <assert.h>
	33	#include <sys/syscall.h>
	34	#include <sched.h>
	35
	36	#include <urcu/arch.h>
	37
	38	/* hardcoded number of CPUs */
	39	#define NR_CPUS 16384
	40
	41	#if defined(_syscall0)
	42	_syscall0(pid_t, gettid)
	43	#elif defined(__NR_gettid)
	44	static inline pid_t gettid(void)
	45	{
	46	return syscall(__NR_gettid);
	47	}
	48	#else
	49	#warning "use pid as tid"
	50	static inline pid_t gettid(void)
	51	{
	52	return getpid();
	53	}
	54	#endif
	55
	56	#ifndef DYNAMIC_LINK_TEST
	57	#define _LGPL_SOURCE
	58	#else
	59	#define debug_yield_read()
	60	#endif
	61	#include <urcu.h>
	62
	63	struct test_array {
	64	int a;
	65	};
	66
	67	static volatile int test_go, test_stop;
	68
	69	static unsigned long wdelay;
	70
	71	static struct test_array *test_rcu_pointer;
	72
	73	static unsigned long duration;
	74
	75	/* read-side C.S. duration, in loops */
	76	static unsigned long rduration;
	77
	78	static inline void loop_sleep(unsigned long l)
	79	{
	80	while(l-- != 0)
	81	cpu_relax();
	82	}
	83
	84	static int verbose_mode;
	85
	86	#define printf_verbose(fmt, args...) \
	87	do { \
	88	if (verbose_mode) \
	89	printf(fmt, args); \
	90	} while (0)
	91
	92	static unsigned int cpu_affinities[NR_CPUS];
	93	static unsigned int next_aff = 0;
	94	static int use_affinity = 0;
	95
	96	pthread_mutex_t affinity_mutex = PTHREAD_MUTEX_INITIALIZER;
	97
	98	static void set_affinity(void)
	99	{
	100	cpu_set_t mask;
	101	int cpu;
	102	int ret;
	103
	104	if (!use_affinity)
	105	return;
	106
	107	ret = pthread_mutex_lock(&affinity_mutex);
	108	if (ret) {
	109	perror("Error in pthread mutex lock");
	110	exit(-1);
	111	}
	112	cpu = cpu_affinities[next_aff++];
	113	ret = pthread_mutex_unlock(&affinity_mutex);
	114	if (ret) {
	115	perror("Error in pthread mutex unlock");
	116	exit(-1);
	117	}
	118	CPU_ZERO(&mask);
	119	CPU_SET(cpu, &mask);
	120	sched_setaffinity(0, sizeof(mask), &mask);
	121	}
	122
	123	/*
	124	* returns 0 if test should end.
	125	*/
	126	static int test_duration_write(void)
	127	{
	128	return !test_stop;
	129	}
	130
	131	static int test_duration_read(void)
	132	{
	133	return !test_stop;
	134	}
	135
	136	static unsigned long long __thread nr_writes;
	137	static unsigned long long __thread nr_reads;
	138
	139	static unsigned int nr_readers;
	140	static unsigned int nr_writers;
	141
	142	pthread_mutex_t rcu_copy_mutex = PTHREAD_MUTEX_INITIALIZER;
	143
	144	void rcu_copy_mutex_lock(void)
	145	{
	146	int ret;
	147	ret = pthread_mutex_lock(&rcu_copy_mutex);
	148	if (ret) {
	149	perror("Error in pthread mutex lock");
	150	exit(-1);
	151	}
	152	}
	153
	154	void rcu_copy_mutex_unlock(void)
	155	{
	156	int ret;
	157
	158	ret = pthread_mutex_unlock(&rcu_copy_mutex);
	159	if (ret) {
	160	perror("Error in pthread mutex unlock");
	161	exit(-1);
	162	}
	163	}
	164
	165	/*
	166	* malloc/free are reusing memory areas too quickly, which does not let us
	167	* test races appropriately. Use a large circular array for allocations.
	168	* ARRAY_SIZE is larger than nr_writers, which insures we never run over our tail.
	169	*/
	170	#define ARRAY_SIZE (1048576 * nr_writers)
	171	#define ARRAY_POISON 0xDEADBEEF
	172	static int array_index;
	173	static struct test_array *test_array;
	174
	175	static struct test_array *test_array_alloc(void)
	176	{
	177	struct test_array *ret;
	178	int index;
	179
	180	rcu_copy_mutex_lock();
	181	index = array_index % ARRAY_SIZE;
	182	assert(test_array[index].a == ARRAY_POISON \|\|
	183	test_array[index].a == 0);
	184	ret = &test_array[index];
	185	array_index++;
	186	if (array_index == ARRAY_SIZE)
	187	array_index = 0;
	188	rcu_copy_mutex_unlock();
	189	return ret;
	190	}
	191
	192	static void test_array_free(struct test_array *ptr)
	193	{
	194	if (!ptr)
	195	return;
	196	rcu_copy_mutex_lock();
	197	ptr->a = ARRAY_POISON;
	198	rcu_copy_mutex_unlock();
	199	}
	200
	201	void thr_reader(void _count)
	202	{
	203	unsigned long long *count = _count;
	204	struct test_array *local_ptr;
	205
	206	printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
	207	"reader", pthread_self(), (unsigned long)gettid());
	208
	209	set_affinity();
	210
	211	rcu_register_thread();
	212
	213	while (!test_go)
	214	{
	215	}
	216	smp_mb();
	217
	218	for (;;) {
	219	rcu_read_lock();
	220	local_ptr = rcu_dereference(test_rcu_pointer);
	221	debug_yield_read();
	222	if (local_ptr)
	223	assert(local_ptr->a == 8);
	224	if (unlikely(rduration))
	225	loop_sleep(rduration);
	226	rcu_read_unlock();
	227	nr_reads++;
	228	if (unlikely(!test_duration_read()))
	229	break;
	230	}
	231
	232	rcu_unregister_thread();
	233
	234	*count = nr_reads;
	235	printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
	236	"reader", pthread_self(), (unsigned long)gettid());
	237	return ((void*)1);
	238
	239	}
	240
	241	void thr_writer(void _count)
	242	{
	243	unsigned long long *count = _count;
	244	struct test_array new, old;
	245
	246	printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
	247	"writer", pthread_self(), (unsigned long)gettid());
	248
	249	set_affinity();
	250
	251	while (!test_go)
	252	{
	253	}
	254	smp_mb();
	255
	256	for (;;) {
	257	new = test_array_alloc();
	258	new->a = 8;
	259	old = rcu_xchg_pointer(&test_rcu_pointer, new);
	260	synchronize_rcu();
	261	if (old)
	262	old->a = 0;
	263	test_array_free(old);
	264	nr_writes++;
	265	if (unlikely(!test_duration_write()))
	266	break;
	267	if (unlikely(wdelay))
	268	loop_sleep(wdelay);
	269	}
	270
	271	printf_verbose("thread_end %s, thread id : %lx, tid %lu\n",
	272	"writer", pthread_self(), (unsigned long)gettid());
	273	*count = nr_writes;
	274	return ((void*)2);
	275	}
	276
	277	void show_usage(int argc, char **argv)
	278	{
	279	printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
	280	#ifdef DEBUG_YIELD
	281	printf(" [-r] [-w] (yield reader and/or writer)");
	282	#endif
	283	printf(" [-d delay] (writer period (us))");
	284	printf(" [-c duration] (reader C.S. duration (in loops))");
	285	printf(" [-v] (verbose output)");
	286	printf(" [-a cpu#] [-a cpu#]... (affinity)");
	287	printf("\n");
	288	}
	289
	290	int main(int argc, char **argv)
	291	{
	292	int err;
	293	pthread_t tid_reader, tid_writer;
	294	void *tret;
	295	unsigned long long count_reader, count_writer;
	296	unsigned long long tot_reads = 0, tot_writes = 0;
	297	int i, a;
	298
	299	if (argc < 4) {
	300	show_usage(argc, argv);
	301	return -1;
	302	}
	303
	304	err = sscanf(argv[1], "%u", &nr_readers);
	305	if (err != 1) {
	306	show_usage(argc, argv);
	307	return -1;
	308	}
	309
	310	err = sscanf(argv[2], "%u", &nr_writers);
	311	if (err != 1) {
	312	show_usage(argc, argv);
	313	return -1;
	314	}
	315
	316	err = sscanf(argv[3], "%lu", &duration);
	317	if (err != 1) {
	318	show_usage(argc, argv);
	319	return -1;
	320	}
	321
	322	for (i = 4; i < argc; i++) {
	323	if (argv[i][0] != '-')
	324	continue;
	325	switch (argv[i][1]) {
	326	#ifdef DEBUG_YIELD
	327	case 'r':
	328	yield_active \|= YIELD_READ;
	329	break;
	330	case 'w':
	331	yield_active \|= YIELD_WRITE;
	332	break;
	333	#endif
	334	case 'a':
	335	if (argc < i + 2) {
	336	show_usage(argc, argv);
	337	return -1;
	338	}
	339	a = atoi(argv[++i]);
	340	cpu_affinities[next_aff++] = a;
	341	use_affinity = 1;
	342	printf_verbose("Adding CPU %d affinity\n", a);
	343	break;
	344	case 'c':
	345	if (argc < i + 2) {
	346	show_usage(argc, argv);
	347	return -1;
	348	}
	349	rduration = atol(argv[++i]);
	350	break;
	351	case 'd':
	352	if (argc < i + 2) {
	353	show_usage(argc, argv);
	354	return -1;
	355	}
	356	wdelay = atol(argv[++i]);
	357	break;
	358	case 'v':
	359	verbose_mode = 1;
	360	break;
	361	}
	362	}
	363
	364	printf_verbose("running test for %lu seconds, %u readers, %u writers.\n",
	365	duration, nr_readers, nr_writers);
	366	printf_verbose("Writer delay : %lu loops.\n", wdelay);
	367	printf_verbose("Reader duration : %lu loops.\n", rduration);
	368	printf_verbose("thread %-6s, thread id : %lx, tid %lu\n",
	369	"main", pthread_self(), (unsigned long)gettid());
	370
	371	test_array = malloc(sizeof(test_array) ARRAY_SIZE);
	372	tid_reader = malloc(sizeof(tid_reader) nr_readers);
	373	tid_writer = malloc(sizeof(tid_writer) nr_writers);
	374	count_reader = malloc(sizeof(count_reader) nr_readers);
	375	count_writer = malloc(sizeof(count_writer) nr_writers);
	376
	377	next_aff = 0;
	378
	379	for (i = 0; i < nr_readers; i++) {
	380	err = pthread_create(&tid_reader[i], NULL, thr_reader,
	381	&count_reader[i]);
	382	if (err != 0)
	383	exit(1);
	384	}
	385	for (i = 0; i < nr_writers; i++) {
	386	err = pthread_create(&tid_writer[i], NULL, thr_writer,
	387	&count_writer[i]);
	388	if (err != 0)
	389	exit(1);
	390	}
	391
	392	smp_mb();
	393
	394	test_go = 1;
	395
	396	sleep(duration);
	397
	398	test_stop = 1;
	399
	400	for (i = 0; i < nr_readers; i++) {
	401	err = pthread_join(tid_reader[i], &tret);
	402	if (err != 0)
	403	exit(1);
	404	tot_reads += count_reader[i];
	405	}
	406	for (i = 0; i < nr_writers; i++) {
	407	err = pthread_join(tid_writer[i], &tret);
	408	if (err != 0)
	409	exit(1);
	410	tot_writes += count_writer[i];
	411	}
	412
	413	printf_verbose("total number of reads : %llu, writes %llu\n", tot_reads,
	414	tot_writes);
	415	printf("SUMMARY %-25s testdur %4lu nr_readers %3u rdur %6lu "
	416	"nr_writers %3u "
	417	"wdelay %6lu nr_reads %12llu nr_writes %12llu nr_ops %12llu\n",
	418	argv[0], duration, nr_readers, rduration,
	419	nr_writers, wdelay, tot_reads, tot_writes,
	420	tot_reads + tot_writes);
	421	test_array_free(test_rcu_pointer);
	422	free(test_array);
	423	free(tid_reader);
	424	free(tid_writer);
	425	free(count_reader);
	426	free(count_writer);
	427	return 0;
	428	}