bug#1089: About #1089: Bug report: Hight CPU loading on scrolling

[Chong Yidong]

Konstantin <Kostafey@yandex.ru> writes:

> emacs-from-cvs-090503 is not free of this bug.

> If we set scroll 'by line' like this
> (setq scroll-step 1)
>
> we can open rather long file (like emacs tutorial)
> and press down buton for a some peiod of time.
> After some smooth scroll period CPU loading increase,
> so 'glitches' or scroll interrupts take place.

The glitches are likely due to font locking taking place, and the
subsequent garbage collection.  If you disable font lock, you won't see
it.  Also, if you scroll through the file a second time, you also won't
see it.