struct timespec tp; 

while (1) {
    ibv_get_cq_event();  // Only necessary for event based polling

    while (ibv_poll_cq()) {   
        clock_gettime(CLOCK_MONOTONIC, &tp);

        /**
         * Save tp and message identifier in an array and
         * return as soon as possible, so that as little
         * as possible time is lost before polling goes on.
         */
    }   

    ibv_req_notify_cq(); // Only necessary for event based polling
}