Re: C mode too slow

[Alan Mackenzie <acm@muc.de>]

Hi, Stefan

>> _and_ because editing lisp.h is virtually impossible these days.  I
>> have to use an old Emacs - almost each editing step takes about 15
>> secs here with the more recent Emacs versions :-(

> I tend to find editing code such as lisp.h too slow as well.  Can we
> do something about it?

lisp.h is slow in "brace desserts", since CC Mode uses braces as anchor
points, particularly whilst font locking.  This should have been fixed
by the optimisation of c-parse-state.

However, comparing the trunk with Emacs 23.3 the number of calls to
c-parse-state has increased by a factor of ~9, cancelling out the
optimisation.  :-(  I'm looking to see why this has happened.

I'm actually looking at a large file (without a single brace) called
AT91SAM9263_INC.h, the one which triggered this optimisation.  What
seems to me slow in lisp.h is scrolling over areas which haven't yet
been fontified since loading.  Once that is done, I think things move at
a decent speed.  Is there anything particular, other than initial
scrolling, which is very slow in lisp.h?

-- 
Alan Mackenzie (Nuremberg, Germany).