Re: M-x compile output sometimes delayed

[Richard Stallman]

    I do M-x compile.  I see the output in fits and starts, not every 4
    seconds.

That certainly should not happen.  It does not fail for me, though.
Can anyone reproduce this and debug it?

Eli wrote:

    I think you forget about I/O buffering.  Emacs runs subordinate processes
    via a pipe, and pipes are buffered by the system.

Sure, but unless Emacs is busy, that should only result in a very
short delay before Emacs wakes up, reads the data, puts it in the
buffer, and displays it.  If Emacs fails to do this promptly,
that is indeed a bug in Emacs.

    In addition, Emacs only checks whether there was input from a subprocess
    when it's not busy doing other things, so that could account for additional
    delays.

That is true, but I get the impression that Emacs was not doing any
other computation in that test case.  He said the processor was 99%
idle, which it would not have been if Emacs had been running the whole
time.