[pphaneuf]

Adding/removing from the poll() array is more or less free, but with epoll, you have to use epoll_ctl(), so you'd definitely want an hysteresis to avoid bouncing things around too much.

[zedshaw]

Interesting, you're like the 3rd or 4th person who's mentioned hysteresis.

[rbanffy]

It's a fairly common idea.

[pphaneuf]

As in "only the 3rd or 4th" (so I'm possibly clever), or as in "a bunch of people"? I don't know your sample size. :-)