Re: slow open() calls and o_nonblock

[Davide Libenzi <davidel@xmailserver.org>]

On Sun, 3 Jun 2007, Aaron Wiebe wrote:

> (ps.  having come from the socket side of the fence, its incredibly
> frustrating to be unable to poll() or epoll regular file FDs --
> Especially knowing that the kernel is translating them into a TCP
> socket to do NFS anyway.  Please add regular files to epoll and give
> me a way to do the opens in the same fasion as connects!)

You may want to follow Ingo and Zach work on syslets/threadlets. If that 
goes in, you can make *any* syscall asynchronous.
I ended up writing a userspace library, to cover the same exact problem 
you have:

http://www.xmailserver.org/guasi.html

I basically host an epoll_wait (containing all my sockets, pipes, etc) 
inside a GUASI async request, where other non-pollable async requests are 
hosted. So guasi_fetch() becomes my main event collector, and when the 
epoll_wait async request show up, I handle all the events in there.
This is a *very-trivial* HTTP server using such solution (coroutines, 
epoll and GUASI):

http://www.xmailserver.org/cghttpd-home.html



- Davide


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