Re: sit-for

[David Kastrup <dak@gnu.org>]

Chong Yidong <cyd@stupidchicken.com> writes:

> David Kastrup <dak@gnu.org> writes:
>
>> 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.
>
> I haven't seen this problem in my usage of gnus.

It is not just gnus.  And it is not easy to see: Emacs gets somewhat
sluggish, sometimes the cursor blinks quite less than expected, and
CPU usage goes up, up, up, which is of course mostly noticeable when
you have power management, and the fans start waking up.

> It would be helpful if you could be more specific: does the problem
> happen with the 2006-07-26 change to `read-event'?

Already before.  I have now recompiled Emacs and will see whether this
changes something.

> If so, did it start to happen at that time, or did it already happen
> after the Lisp-level `sit-for' was implemented? 
>
> If it only started after the `read-event' change, one possibility is
> that read_char is getting stuck somewhere before we get to the point
> where we check if the timeout has elapsed.
>
>> 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.
>
> That's the story of the Emacs 22 feature freeze.


-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum