Re: [boost] [review] Asio formal review.

From: Jody Hagins (jody-boost-011304_at_[hidden])
Date: 2005-12-22 21:22:31

On Thu, 22 Dec 2005 21:16:11 -0000 (GMT)
"christopher baus" <christopher_at_[hidden]> wrote:

> Interesting.  Could you give an example where select() is faster than
> epoll()?  I suspect it is with smaller numbers of file descriptors.

OK.  I have a small example (but I'm out of time to do more).  The
problem with epoll() is when you have a large number of FDs that are all
ready.  If you epoll_wait() for as many events as you have FDs you get
MUCH worse performance than poll() or select.  If you just wait on 1 FD
with epoll_wait(), you can call the system call a bunch more times, but
then again, you have to make a system call for every FD that is ready,
which is more expensive over lots of FDs.

Does that make sense?