timer->elapse.tv_sec += timer->stop.tv_sec - timer->start.tv_sec;
timer->elapse.tv_nsec += timer->stop.tv_nsec - timer->start.tv_nsec;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &(timer->start));
timer->elapse.tv_sec += timer->stop.tv_sec - timer->start.tv_sec;
timer->elapse.tv_nsec += timer->stop.tv_nsec - timer->start.tv_nsec;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &(timer->start));