Add timing tests

[urcu.git] / test_urcu_timing.c

/*
 * test_urcu.c
 *
 * Userspace RCU library - test program
 *
 * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 *
 * Distributed under GPLv2
 */

#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>

#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

#define rdtscll(val) do { \
     unsigned int __a,__d; \
     asm volatile("rdtsc" : "=a" (__a), "=d" (__d)); \
     (val) = ((unsigned long)__a) | (((unsigned long)__d)<<32); \
} while(0)

typedef unsigned long long cycles_t;

static inline cycles_t get_cycles (void)
{
        unsigned long long ret = 0;

        rdtscll(ret);
        return ret;
}

#include "urcu.h"

struct test_array {
	int a;
};

static struct test_array *test_rcu_pointer;

#define OUTER_READ_LOOP	2000U
#define INNER_READ_LOOP	100000U
#define READ_LOOP ((unsigned long long)OUTER_READ_LOOP * INNER_READ_LOOP)

#define WRITE_LOOP 2000U

#define NR_READ 10
#define NR_WRITE 9

static cycles_t reader_time[NR_READ] __attribute__((aligned(128)));

void *thr_reader(void *arg)
{
	int qparity, i, j;
	struct test_array *local_ptr;
	cycles_t time1, time2;

	printf("thread_begin %s, thread id : %lx, tid %lu\n",
			"reader", pthread_self(), (unsigned long)gettid());
	sleep(2);

	urcu_register_thread();

	time1 = get_cycles();
	for (i = 0; i < OUTER_READ_LOOP; i++) {
		for (j = 0; j < INNER_READ_LOOP; j++) {
			qparity = rcu_read_lock();
			local_ptr = rcu_dereference(test_rcu_pointer);
			if (local_ptr) {
				assert(local_ptr->a == 8);
			}
			rcu_read_unlock(qparity);
		}
	}
	time2 = get_cycles();

	urcu_unregister_thread();

	reader_time[(unsigned long)arg] = time2 - time1;

	sleep(2);
	printf("thread_end %s, thread id : %lx, tid %lu\n",
			"reader", pthread_self(), (unsigned long)gettid());
	return ((void*)1);

}

void *thr_writer(void *arg)
{
	int i;
	struct test_array *new, *old;

	printf("thread_begin %s, thread id : %lx, tid %lu\n",
			"writer", pthread_self(), (unsigned long)gettid());
	sleep(2);

	for (i = 0; i < WRITE_LOOP; i++) {
		new = malloc(sizeof(struct test_array));
		rcu_write_lock();
		old = test_rcu_pointer;
		if (old) {
			assert(old->a == 8);
		}
		new->a = 8;
		old = urcu_publish_content((void **)&test_rcu_pointer, new);
		rcu_write_unlock();
		/* can be done after unlock */
		if (old) {
			old->a = 0;
		}
		free(old);
		usleep(1);
	}

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

int main()
{
	int err;
	pthread_t tid_reader[NR_READ], tid_writer[NR_WRITE];
	void *tret;
	int i;
	cycles_t tot_time = 0;

	printf("thread %-6s, thread id : %lx, tid %lu\n",
			"main", pthread_self(), (unsigned long)gettid());

	for (i = 0; i < NR_READ; i++) {
		err = pthread_create(&tid_reader[i], NULL, thr_reader,
				     (void *)(long)i);
		if (err != 0)
			exit(1);
	}
	for (i = 0; i < NR_WRITE; i++) {
		err = pthread_create(&tid_writer[i], NULL, thr_writer, NULL);
		if (err != 0)
			exit(1);
	}

	sleep(10);

	for (i = 0; i < NR_READ; i++) {
		err = pthread_join(tid_reader[i], &tret);
		if (err != 0)
			exit(1);
		tot_time += reader_time[i];
	}
	for (i = 0; i < NR_WRITE; i++) {
		err = pthread_join(tid_writer[i], &tret);
		if (err != 0)
			exit(1);
	}
	free(test_rcu_pointer);
	printf("Time per read : %g cycles\n",
	       (double)tot_time / ((double)NR_READ * (double)READ_LOOP));

	return 0;
}