Re: How to increat [sic.] max open files?

Richard Gooch (rgooch@atnf.CSIRO.AU)
Wed, 8 Jan 1997 10:29:44 +1100


rdm@tad.micro.umn.edu writes:
> Richard Gooch:
> > If you really want the kernel to help in a situation where you have
> > 20 000 connections, how about implementing the following:
> >
> > a system call similar to select(2) or poll(2), except that instead of
> > the list of FDs being used for input to the kernel and return from the
> > kernel, have the input and return list separate. The return list is
> > written in a compact form, such that returned FDs are written in the
> > first N entries (where N is the number of returned FDs).
>
> Hrm... there are other alternatives.
>
> [For example, plan9 has a call to read from a set of file descriptors,
> using a "random but fair" policy.
>
> Unfortunately, I don't remember the exact name of the call off the top
> of my head nor do I remember its exact semantics. However, I have the
> impression that it's easier to code into an event loop than select().

Sometimes we don't just want to read: we may want to know when a FD
is ready for writing, or if there is urgent data, or if the other end
has closed (a special case of "input").

Regards,

Richard....