Re: Slow fontification in C mode buffers

[Alan Mackenzie]

Hi, Geoff.

On Thu, Dec 22, 2011 at 12:48:53AM +0800, Geoff Gole wrote:
> > If you're running GNU Emacs, an optimisation was introduced in Emacs
> > 23.3 which gave a considerable speed-up to such code.  This optimisation
> > found its way into the XEmacs CC Mode package in September.  I _hope_
> > your version of Emacs is prior to one of these, in which case upgrading
> > will give you this benefit.

> > Otherwise, I'll be asking you if you're prepared to give me some
> > timings.

> Well, M-x version gives me GNU Emacs 24.0.91.1 (i686-pc-linux-gnu,
> GTK+ Version 2.12.12) of 2011-11-18, and cc-defs.el has c-version at
> 5.32.2.

> I'd be happy to produce timings. What do you need?

Let's just agree on what we mean by "very slow".  I've just loaded
gl_mangle.h into an Emacs 24 pretest.  I've got a 2.6 GHz Athlon II
processor.  On doing M->, followed by scrolling a up a page at a time,
each operation is taking me less than 1 second.  Of course, once a page
gets fontified, scrolling over it then becomes instantaneous.

How fast/slow is this scrolling on your hardware/software?

-- 
Alan Mackenzie (Nuremberg, Germany).