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Very slow performance #11

jaksz opened this Issue Aug 19, 2015 · 8 comments


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jaksz commented Aug 19, 2015

Whenever org-bullets is enabled, scrolling (and even fast typing) becomes laggy.

I'm running GNU Emacs 24.5.1 (x86_64-apple-darwin13.4.0, NS apple-appkit-1265.21) of 2015-04-10 on

If there is a way I can provide more information (e.g. my about my system, config), please let me know.

This is inside the GUI version of Emacs. Note that there is no lag when using a terminal.


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sabof commented Aug 28, 2015

M-x customize-group jit-lock has some variables that might help. Ex. jit-lock-defer-time


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gavinpc commented Nov 22, 2016

I have experienced the same thing in GNU Emacs 25.1.1 (x86_64-w64-mingw32) of 2016-09-17. The problem is so bad that emacs almost invariably crashes. I have used org-bullets for years without problem, but this has come up immediately on my new machine. This is my first Win10 machine, but also my first quad-density display.

It seems that emacs isn't coping well with the display of extended Unicode characters. For example, if I load the org-bullets source, the lagginess occurs whenever the special characters (that appear literally in the code) come into view, and it goes away when they are out of view. I can also reproduce the lag by running view-hello-file, which contains mostly non-English characters.

So from what I can tell, this is not a problem with org-bullets per se, but with the fact that non-ASCII characters end up being in view effectively all the time, which is apparently problematic on some systems.


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shoover commented Mar 22, 2017

I can hang emacs by scrolling my largest orgmode files in GNU Emacs 25.1.1 (x86_64-w64-mingw32) of 2016-09-17.

To @gavinpc's point that it's a non-ASCII (or general font-lock) problem, even the following simple snippet is enough to cause the hang. I have to disable org-bullets and this fancy list bullets functionality to eliminate the hang.

(defvar org-fancy-list-bullets
  '(("^ +\\([*]\\) "   ; asterisks need a space first to skip headings
     (1 (prog1 () (compose-region (match-beginning 1) (match-end 1) "•"))))
    ("^ *\\([-]\\) "   ; hyphens can start at bol
     (1 (prog1 () (compose-region (match-beginning 1) (match-end 1) "•"))))))
(font-lock-add-keywords 'org-mode org-fancy-list-bullets)

But I tend to use page up and page down so scrolling isn't much of an issue in practice. However, loading these huge files takes several seconds, which is annoying.

By systematically commenting things out in org-bullets, I learned that removing the calls to font-lock-fontify-buffer does positively impact file load time. I was surprised to see it did not break bullets composition. I may be missing something but it seems to still work.

telotortium added a commit to telotortium/emacs.d that referenced this issue Jun 22, 2017

Disable org-bullets mode
It significantly slows down viewing Org
files (sabof/org-bullets#11).

seagle0128 added a commit to seagle0128/.emacs.d that referenced this issue Feb 27, 2018


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Zyst commented May 5, 2018

I have a (maybe?) the same issue.

This is on Windows 10, using emacs-w64-25.3-O2-with-modules.7z from and spacemacs

Here's a .gif with org-bullets on, where I press tab twice as soon as I get into the file. I know slowness can't really translate very well into video, but here goes, there isn't a pause I do at any point. This is all the editor hanging completely:

org bullets hanging

One curious thing to note is that after having the file open for a while, and having opened/closed the items and the like, the performance picks up pretty drastically.

Same thing after disabling org-bullets.

no org bullets, performance is fine

This issue only happens to me on my computer at home. On my work laptop performance is great. So it might either be a specific-piece-of-hardware issue, or it might be an issue that I have a 5k monitor at home, and a 1080p monitor at work. And that's what's making the difference.


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giupo commented Jul 3, 2018

Same issue here with GNU Emacs 26.1 (build 1, x86_64-w64-mingw32) of 2018-05-30 and a display 4k (with powerline-mode and few other things).

The very same Emacs setup at work (with a 1080p as stated by @Zyst ) works very well.


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ihdavids commented Nov 15, 2018

I found this on the all the icons package.
This was a game changer for me on windows and I HIGHLY recommend it for anyone using org-bullets on windows as well!

(setq inhibit-compacting-font-caches t)

Turning that on is night and day for performance on windows for me.


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Zyst commented Nov 16, 2018

@ihdavids can confirm that this really does make an incredible difference


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giupo commented Nov 17, 2018

@ihdavids thanks! this fixes the issue for me.

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