/*
 * mutex1.c
 *
 * $DragonFly: src/test/sysperf/mutex1.c,v 1.2 2006/04/22 22:34:06 dillon Exp $
 */

#include "blib.h"

int *mtx;

int
main(int ac, char **av)
{
    long long count = 0;
    long long max;
    int j;
    int *counter;
    pid_t pid;

    printf("Test simple locked bus cycle mutex latency\n");
    printf("auto-forks two processes for the test with shared memory\n");
    printf("This test is only useful on a SMP box\n");

    start_timing();
    mtx = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
    counter = mtx + 64;
    while (stop_timing(0, NULL) == 0) {
        for (j = 0; j < 100; ++j) {
            try_spin_mtx();
            rel_spin_mtx();
        }
        count += 100;
    }
    max = count;
    *mtx = 0;

    /*
     * Single cpu case
     */
    start_timing();
    for (count = 0; count < max; count += 100) {
        for (j = 0; j < 100; ++j) {
            while (try_spin_mtx() != 0)
                ;
            rel_spin_mtx();     /* release */
            ++counter[64];
        }
    }
    stop_timing(count, "simple_mtx(uncontested/1cpu)");

    if ((pid = fork()) == 0) {
        for (;;) {
            for (j = 0; j < 100; ++j) {
                while (try_spin_mtx() != 0)
                    ;
                rel_spin_mtx(); /* release */
                ++counter[128];
            }
        }
    } else {
        start_timing();
        for (count = 0; count < max; count += 100) {
            for (j = 0; j < 100; ++j) {
                while (try_spin_mtx() != 0)
                    ;
                rel_spin_mtx(); /* release */
                ++counter[64];
            }
        }
        stop_timing(count, "simple_mtx");
        printf("proc1=%d proc2=%d\n", counter[64], counter[128]);
        kill(pid, 9);
    }
    return(0);
}