elapsed(struct timeval *start_tv)
{
    struct timeval  now_tv;

    gettimeofday(&now_tv, NULL);
    return (now_tv.tv_sec - start_tv->tv_sec) * 1000L
	 + (now_tv.tv_usec - start_tv->tv_usec) / 1000L;
}
elapsed(struct timeval *start_tv)
{
    struct timeval  now_tv;

    gettimeofday(&now_tv, NULL);
    return (now_tv.tv_sec - start_tv->tv_sec) * 1000L
	 + (now_tv.tv_usec - start_tv->tv_usec) / 1000L;
}