forkbench.c

#include <unistd.h>
#include <stdio.h>
#include <time.h>

double sec(void) {
    struct timespec tv;

    clock_gettime(CLOCK_MONOTONIC, &tv);

    return tv.tv_sec + tv.tv_nsec / (1000000000.0);
}


static void
test(void)
{
    int nloop = 1024, pid, li;

    double t0 = sec(), t1;
    for (li=0; li<nloop; li++) {
        int st;

        pid = fork();
        if (pid == 0) {
            _exit(0);
        }

        wait(&st);
    }
    t1 = sec();

    printf("fork() %f [msec]\n", ((t1-t0)/nloop)*1000.0);
}


int main()
{
    test();
    test();
}