Re: [O] org-src-fontify-natively makes things very, very slow

[Carsten Dominik]

On 21.3.2011, at 18:06, Eric S Fraga wrote:

> Hello again,
> 
> going back to the original subject of this thread (although thanks all
> for your inputs on yasnippet ;-), I have started working on a new
> document and am finding the slowdown of navigation (next-line) very
> annoying.  In this document, I have two gnuplot source blocks.
> Navigating through them, I get the following results from elp:
> 
> --8<---------------cut here---------------start------------->8---
> next-line                                                     54          
> 5.9466770000  0.1101236481
> previous-line                                                 44          
> 0.4350030000  0.0098864318
> org-encrypt-entries                                           1           
> 0.000424      0.000424
> org-scan-tags                                                 1           
> 0.000368      0.000368
> org-make-tags-matcher                                         1           
> 5.1e-05       5.1e-05
> org-activate-plain-links                                      1           
> 2.4e-05       2.4e-05
> org-raise-scripts                                             1           
> 2.1e-05       2.1e-05
> org-fontify-meta-lines-and-blocks                             1           
> 1.9e-05       1.9e-05
> org-font-lock-hook                                            1           
> 1.9e-05       1.9e-05
> org-outline-level                                             5           
> 1.9e-05       3.8e-06
> org-mode-flyspell-verify                                      14          
> 1.8e-05       1.285...e-06
> org-inlinetask-fontify                                        1           
> 1.5e-05       1.5e-05
> org-activate-footnote-links                                   1           
> 1.5e-05       1.5e-05
> org-unfontify-region                                          1           
> 1.2e-05       1.2e-05
> org-do-emphasis-faces                                         1           
> 1.2e-05       1.2e-05
> org-activate-angle-links                                      1           
> 1.2e-05       1.2e-05
> org-activate-dates                                            1           
> 1.1e-05       1.1e-05
> org-fontify-entities                                          1           
> 1.1e-05       1.1e-05
> --8<---------------cut here---------------end--------------->8---
> 
> From these timings, the font locking doesn't seem to be the issue but
> maybe the overlays are.  However, commenting out the code that Sébastien
> Vauban indicated:
> 
>> Maybe this is (partly?) due to the overlay I added:
>> 
>> #+begin_src emacs-lisp
>>                (overlay-put (make-overlay beg1 block-end)
>>                             'face 'org-block-background))
>> #+end_src
> 
> (well, commenting out the whole condition that includes this code) makes
> no difference at all.

Did you restart Emacs?  Because if you just continued, all those
overlays are there already.

> 
> So, I turned off =org-src-fontify-natively= and things are back to
> normal: next-line is as fast as previous-line.  I can put up without the
> fontification so this is what I am doing now.  
> 
> However, as it's a pity to lose the native fontification, it would be
> nice to solve this problem in another way.  Can anybody suggest any
> other thing to try?

The problem with the multiple overlays that were created
during native fontification is now fixed.  I would be interested
to know if this improves the situation.

- Carsten