Re: [PATCH] epoll more scalable than poll

Davide Libenzi
2002-10-28T22:01:41Z

On Mon, 28 Oct 2002, Martin Waitz wrote:

> hi :)
>
> On Mon, Oct 28, 2002 at 11:14:19AM -0800, Hanna Linder wrote:
> > The results of our testing show not only does the system call
> > interface to epoll perform as well as the /dev interface but also that epoll
> > is many times better than standard poll. No other implementations of poll
> > have performed as well as epoll in any measure. Testing details and results
> > are published here, please take a minute to check it out: http://lse.sourceforge.net/epoll/index.html
> how does this compare to the kqueue mechanism found in {Free,Net}BSD?
> (see http://people.freebsd.org/~jlemon/papers/kqueue.pdf)
>
> i especially like their combined event update/event wait,
> needing only one syscall per poll while building a changelist in
> userspace...
>
> a replacement for poll/select is _really_ needed.
> but i think we should use existing interfaces if possible,
> to reduce the changes needed in userspace.

KQueue has not been tested simply because it does not ( to my knowledge )
have patches to apply to lk. I'd expect kqueue to scale in a similar way
of sys_epoll though. Where for "similar" I mean to not suffer high
connection load drops. About the interface, it looks pretty simple to me :

http://www.xmailserver.org/linux-patches/epoll_create.txt
http://www.xmailserver.org/linux-patches/epoll_ctl.txt
http://www.xmailserver.org/linux-patches/epoll_wait.txt

- Davide