Re: cperl + isearch + font-lock-multiline sometimes very slow

[Chong Yidong <cyd@stupidchicken.com>]

Klaus Zeitler <kzeitler@lucent.com> writes:

>>>>>> "Chong" == Chong Yidong <cyd@stupidchicken.com> writes:
>     Chong> 
>     Chong> I can't reproduce this.  Could you provide a detailed recipe and/or
>     Chong> test file?
>
> I've now managed to reduce my .emacs file from 4000 lines to the following
> 3 lines:
> --- snip ---
> (setq font-lock-multiline t)
> (require 'printing "printing" 'no-error)
> (fset 'perl-mode 'cperl-mode)
> --- snip ---
>
> With these 3 lines I can still observe the problem.
> 1. Start emacs with .emacs containing the 3 lines above
> 2. load a Perl file (not too small), I use perl5db.pl from the Perl distribution
> 3. Watch emacs CPU usage
>
> After approximaetly 25 seconds, the CPU usage climbs for nearly 3 minutes
> to 55% and emacs behaves very sluggish. Afterwards emacs behaves normal.
> No need for isearch, that was obviously a misinterpretation. Don't know
> what the package 'printing' has to do with it. Maybe it's a problem with
> menu-bar updates and stealth fontification.

I still can't reproduce this, using the above .emacs file and
perl5db.pl.  A month or two ago, we fixed such a bug dealing with a
bad interaction between menu-bar updates and stealth fontification;
stealth fontification should no longer trigger menu-bar updates.
Could you just check that you don't have any old files (e.g. of
jit-lock) hanging around in your CVS copy?

Assuming it's not that, please see if it's due to stealth
fontification by changing jit-lock-stealth-time to nil and see if the
problem recurs.  Also, try setting jit-lock-stealth-time to 2 and see
if the problem occurs more quickly.