bug#15876: 24.3.50; Highly degraded performance between rev 114715 and 115006

[Eli Zaretskii]

> From: "Sebastien Vauban" <sva-news@mygooglest.com>
> Date: Tue, 19 Nov 2013 23:52:18 +0100
> Cc: 15876@debbugs.gnu.org
> 
> I don't have yet a minimized Emacs configuration file, but I already can tell
> that, in my full .emacs file, disabling the following line does solve the
> problem!
> 
> --8<---------------cut here---------------start------------->8---
> ;; highlight trailing whitespaces in all modes
> (setq-default show-trailing-whitespace t)
> --8<---------------cut here---------------end--------------->8---
> 
> So, it seems to conflict with something else from my .emacs -- still have to
> find what.
> 
> Does the above ring a bell?

If you enable show-trailing-whitespace only in a few modes (via a mode
hook), does the performance problem remain only in those modes and
disappear in others?