Re: Did something change with respect to Emacs idle loop:

[Richard Stallman]

    You'll actually see this when mplayer is playing something off of
    the local disk while emacs is waiting on an nfs disk  

Are you saying that the problem ONLY happens when Emacs is waiting for
nfs?  I think that's what you're saying, but I'm not 100% sure,
and I'd like to make sure there is no misunderstanding.

If that's the situation, I can guess what the problem might be.

Years ago there were uninterruptible waits in NFS code (I am not sure
which systems this applied to).  That is, a user program (such as
Emacs) would do a system call to use NFS, and that system call would
wait, and it could not be interrupted until the wait finished.  No
signals could be delivered.

If mplayer is trying to output regularly thru a pty to Emacs, Emacs
ought to detect the input and read it every so often.  But Emacs can't
do that if it is in an uninterruptible wait.  So the output buffer
would get full, and then mplayer would hang.

It would be the same if Emacs is computing without waiting for a long
time, since Emacs does not read process output while it is computing.
In that case you could fix the problem by calling
accept-process-output from time to time.  But if NFS causes an
uninterruptible wait, there is nothing Emacs can do about it.