/*
 * umtx1.c
 */

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/errno.h>
#include <pthread.h>
#include <machine/cpufunc.h>
#include <machine/atomic.h>
#include "blib.h"

static void *do_child(void *arg);
static void *do_parent(void *arg);

u_int mtx;
u_long total;

int
main(int ac, char **av)
{
        pthread_t td1;
        pthread_t td2;
        int n;
        int k;
        int status;

        printf("tests umtx hand-off loop\n");
        for (n = 1; n; --n) {
                if (fork() == 0) {
                        start_timing();
                        for (k = 0; k < 10; ++k) {
                                pthread_create(&td1, NULL, do_child, NULL);
                                pthread_create(&td2, NULL, do_parent, NULL);
                                pthread_join(td2, NULL);
                                pthread_join(td1, NULL);
                        }
                        stop_timing(total, "total");
                        _exit(0);
                }
        }
        while (wait3(&status, 0, NULL) <= 0 || errno == EINTR)
                ;

        return 0;
}

static
void *
do_child(void *arg __unused)
{
        for (;;) {
                while (mtx == 0)
                        umtx_sleep(&mtx, 0, 0);
                if (atomic_swap_int(&mtx, 0) == 2) {
                        umtx_wakeup(&mtx, 0);
                        pthread_yield();
                        break;
                }
                umtx_wakeup(&mtx, 0);
        }
        return NULL;
}

static
void *
do_parent(void *arg __unused)
{
        int j;
        int loops;

        for (j = 0; j < 1000000; ++j) {
                atomic_swap_int(&mtx, 1);
                umtx_wakeup(&mtx, 0);
                pthread_yield();
                while (mtx == 1)
                        umtx_sleep(&mtx, 1, 0);
        }
        start_timing();
        for (j = 0; j < 1000000; ++j) {
                atomic_swap_int(&mtx, 1);
                umtx_wakeup(&mtx, 0);
                while (mtx == 1)
                        umtx_sleep(&mtx, 1, 0);
        }
        stop_timing(j, "mtx1");
        atomic_add_long(&total, j * 2);

        atomic_swap_int(&mtx, 2);
        umtx_wakeup(&mtx, 0);
        while (mtx == 2)
                umtx_sleep(&mtx, 2, 0);

        return NULL;
}