Things were like that at one point in time, but file descriptors turn out 
to introduce a huge gaping security hole with SUID programs.  The problem 
is that any event context is closely tied to the address space of the 
thread issuing the syscalls, and file descriptors do not have this close 
binding.

Can you go into that hole in more detail?

Except that you're not usually pulling a full ring worth of events at a 
time, more often just one.

OK, but then to wait for it you were already sleeping in the kernel, right?

Clearly we should port httpd to kevents and take some measurements :)

- z