bug#21028: Performance regression in revision af1a69f4d17a482c359d98c00ef86fac835b5fac (Apr 2014).

[Clément Pit--Claudel]

On 2016-03-03 15:27, Eli Zaretskii wrote:
> The only way forward I see is to reproduce the problem described in
> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17125#26 and in
> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17125#29, in the "fast"
> case (i.e. without the changes that fixed that bug), and then look for
> a different solution for that problem.  If you can reproduce that,
> please step through x_default_font_parameter and x_default_parameter,
> and tell how does the empty vector in the cache come into play.  Then
> we can try some other solution for that.

Belated thanks. I will try to look into this.

I've made more progress towards making this reproducible, too. My current repro 
requires XITS Math 
(https://github.com/khaledhosny/xits-math/blob/master/xits-mathbold.otf), and 
Segoe UI Emoji.  Do you have a machine with that font? If so, could you try the 
following?

    emacs-24.5 -Q -mm -l 21028.el 21028 -f prettify-symbols-mode

I've attached 21028.el and 21028. When I run this command, each full redisplay 
takes about 5 seconds; same for pointer motion.

Clément.

21028.el
Description: Text Data

21028
Description: Text document

signature.asc
Description: OpenPGP digital signature