Re: Slow movement in large buffers

[Nick Dokos <nicholas.dokos@hp.com>]

Carsten Dominik <carsten.dominik@gmail.com> wrote:

> 
> On Mar 15, 2011, at 4:25 AM, Matt Lundin wrote:
> 
> > I've been navigating the org-issues file (14000+ lines) and have found
> > movement within the file to be fairly slow. Sometimes Emacs will lock up
> > for several seconds.
> > 
> > For instance, to move from the level one heading "* Other" to "* Closed
> > issues" when the outline is folded takes over three seconds:
> > 
> > --8<---------------cut here---------------start------------->8---
> > next-line     1           3.015289      3.015289
> > --8<---------------cut here---------------end--------------->8---
> > 
> 
> Wow, this is really bad.
> Could you use elp and instrument org, outline,
> and font-lock, and do that motion and report
> the results?
> 
> > In my experience, the maximum workable size of org files is around
> > 10,000 lines. Beyond that, Emacs starts to spin its wheels.
> 
> Not good at all.
> 
> - Carsten
> 
> > 
> > Do others have the same experience? If so, does anyone have any tips on
> > how to diagnose this further?
> > 
> > (insert "\n" emacs-version)
> > 23.3.1
> > 
> > (insert "\n" org-version)
> > 7.5
> > 

FWIW, I opened org-issues.org and followed Matt's lead: at first, I got
almost instant response going from Other to Closed (using arrow-down)
and a slight hesitation (< 0.5s) going from Other to the previous
headline (Development Tasks).  After noodling around for a while
(including the motions that Eric F. suggested and getting no delays
there), I tried it again and could discern no delay going either
way. And I do run flyspell in org buffers.

This is on a fairly recent vintage laptop with an i7 quad core processor
(2.67GHz) and 4G of memory. That probably explains some of the difference
I see. Matt, what kind of hardware are you using?

Nick