font-lock has become far too slow

font-lock has become far too slow

[John Wiegley]

Starting very recently, font-lock (using jit-lock) has become so slow
that Emacs can no longer keep up with my typing -- on a modern, 1.25
GHz PowerBook G4.  I haven't profiled things yet, so does anyone know
what was added that might make things this slow?  I compiled with -O3
-fomit-frame-pointer, but still am forced to turn off font-lock mode.

John

Re: font-lock has become far too slow

[John Wiegley]

John Wiegley <johnw@gnu.org> writes:

> Starting very recently, font-lock (using jit-lock) has become so
> slow that Emacs can no longer keep up with my typing -- on a modern,
> 1.25 GHz PowerBook G4.  I haven't profiled things yet, so does
> anyone know what was added that might make things this slow?  I
> compiled with -O3 -fomit-frame-pointer, but still am forced to turn
> off font-lock mode.

It looks like it's more than just font-lock.  With font-lock off, if I
hold down C-p to move up in the buffer, drawing new pages takes up to
a full second (subjective).  And typing past the end of a line has a
hard time keeping up with my typing.  Even typing this message is very
laggy.  I will have to do some profiling to see what it going on.
Nothing in my configuration has changed very drastically since
February, when things were working quite nicely.

John

Re: font-lock has become far too slow

[Eli Zaretskii]

> From: John Wiegley <johnw@gnu.org>
> Date: Tue, 27 Apr 2004 15:44:36 -0700
> 
> It looks like it's more than just font-lock.

Does it happen in "emacs -q --no-site-file"?

> With font-lock off, if I hold down C-p to move up in the buffer,
> drawing new pages takes up to a full second (subjective).  And
> typing past the end of a line has a hard time keeping up with my
> typing.

How exactly did you turn off font-lock?

The package elp.el should allow you to profile Emacs on the Lisp
level, so you could see what takes so long to redraw the screen.

Re: font-lock has become far too slow

[Kim F. Storm]

John Wiegley <johnw@gnu.org> writes:

> John Wiegley <johnw@gnu.org> writes:
> 
> > Starting very recently, font-lock (using jit-lock) has become so
> > slow that Emacs can no longer keep up with my typing -- on a modern,
> > 1.25 GHz PowerBook G4.  I haven't profiled things yet, so does
> > anyone know what was added that might make things this slow?  I
> > compiled with -O3 -fomit-frame-pointer, but still am forced to turn
> > off font-lock mode.
> 
> It looks like it's more than just font-lock.  With font-lock off, if I
> hold down C-p to move up in the buffer, drawing new pages takes up to
> a full second (subjective).  And typing past the end of a line has a
> hard time keeping up with my typing.  Even typing this message is very
> laggy.  I will have to do some profiling to see what it going on.
> Nothing in my configuration has changed very drastically since
> February, when things were working quite nicely.

I just installed a fix for a problem causing excessive redisplay.

Please see if this problem has been fixed as well.

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk

Re: font-lock has become far too slow

[John Wiegley]

no-spam@cua.dk (Kim F. Storm) writes:

> I just installed a fix for a problem causing excessive redisplay.
>
> Please see if this problem has been fixed as well.

Yes, this does seem to fix the slowdown problem.

John

Re: font-lock has become far too slow

[John Wiegley]

Eli Zaretskii <eliz@gnu.org> writes:

> How exactly did you turn off font-lock?

M-x global-font-lock-mode

> The package elp.el should allow you to profile Emacs on the Lisp
> level, so you could see what takes so long to redraw the screen.

How do I profile the entire Lisp subsystem?

John

Re: font-lock has become far too slow

[Kevin Rodgers]

John Wiegley wrote:
 >>The package elp.el should allow you to profile Emacs on the Lisp
 >>level, so you could see what takes so long to redraw the screen.
 >
 > How do I profile the entire Lisp subsystem?

Does `M-x elp-instrument-package RET \` RET' work?

-- 
Kevin Rodgers

Re: font-lock has become far too slow

[Stefan Monnier]

> Does `M-x elp-instrument-package RET \` RET' work?

IIRC it broke Emacs.  At some point I got it to work, but it might be
broken again (or maybe I didn't install all the necessary fixes).
So be careful with it.

The problems come from things like "profiling functions used by the
profiling code".


        Stefan