sit-for

[David Kastrup]

Since we have the new sit-for implementation, I have a lot of times
when Emacs just pauses in busy waiting for input.  This happens
spontaneously.  One situation where it happens frequently is when
reading news with gnus.  If I type C-g at such a time with
debug-on-quit set to t, I just get


Debugger entered--Lisp error: (quit)

in the *Backtrace* buffer.

In contrast, when Emacs is actually waiting in a non-busy wait for
input, the backtrace is

Debugger entered--Lisp error: (quit)
  signal(quit nil)
  keyboard-quit()
  call-interactively(keyboard-quit)

and this is what I would expect without those random lockups which
tend to last for seconds and gobble up CPU power.

This is really a nuisance.  The change to sit-for is a fundamental
change to some core mechanism of Emacs, and it is currently seemingly
breaking quite a few things, apart from causing strange effects.

It does not look like the implications of this code are obvious to
anybody.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum