Subject: Re: bug#23377: 25.0.93; Completion is extremely slow for insert-char

From: Paul Eggert <[email-masked]>
Date: Tue, 26 Apr 2016 08:49:39 -0700

On 04/26/2016 04:51 AM, Stefan Monnier wrote:
> It's not adding a feature.  It's disabling a feature with an easy to use
> switch to re-enable it.
> Don't make it a defcustom, just a defvar.

OK, thanks, that's easy. Proposed patch (to emacs-25) attached.

On my platform the performance is pretty bad without this, even without 
listing all the characters. I particularly notice it when I run Emacs 
over X from my office to home, something that's normally quite 
tolerable. I had already noticed this performance problem, but hadn't 
gotten around to looking into it until N. Jackson's bug report made it 
clear I wasn't alone.

In the long run there are some things we can do to improve things (e.g., 
not compute menu items until displayed, not display those ugly boxed and 
useless hexadecimal numbers, use a better menu that lets users choose 
characters by shape rather than just by name, etc.) that could let us 
turn annotation on by default, but that all needs to wait until after 
Emacs 25 comes out.