[sheepdog] [PATCH v2 1/2] lib: prioritize events for epoll() and enhance event loop

[Liu Yuan]

On 12/22/2012 01:23 AM, Hitoshi Mitake wrote:
> +	 * we have to retrieve the number of prioritized events here, because
> +	 * nr_prioritized_events is increased in event handlers
> +	 */
> +	prioritized = nr_prioritized_events;
>  
> -	nr = epoll_wait(efd, events, ARRAY_SIZE(events), TICK * 1000);
> +	nr = epoll_wait(efd, polled_events, nr_events, TICK * 1000);
>  	if (nr < 0) {
>  		if (errno == EINTR)
>  			return;
>  		eprintf("epoll_wait failed: %m\n");
>  		exit(1);
>  	} else if (nr) {
> +		if (prioritized)
> +			qsort(polled_events, nr, sizeof(struct epoll_event),
> +				epoll_event_cmp);

It seems that we need to call qsort every time since we
nr_prioritized_events is always > 0 for now. I guess we need a better
method to test need_sort case to optimize for most cases that don't
need_sort.

Thanks,
Yuan