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

[Eric S Fraga <e.fraga@ucl.ac.uk>]

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.

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?

Thanks,
eric

-- 
: Eric S Fraga (GnuPG: 0xC89193D8FFFCF67D) in Emacs 24.0.50.1
: using Org-mode version 7.5 (release_7.5.91.g38c6b)