Subject: bug#20611: 24.4; mutt slow in ansi-term

From: Eli Zaretskii <[email-masked]>
Date: Mon, 11 Apr 2016 19:01:15 +0300

> From: Alexis <[email-masked]>
> Cc: Mark Hindley <[email-masked]>, [email-masked], [email-masked]
> Date: Mon, 11 Apr 2016 08:22:09 +1000
> 
> Context: Debian Jessie x86_64 / i5-2410M.
> 
> i also observe noticeable lag in the above situation, on both on 
> 24.5 and on master as at d6ea6453. The lag is worse on the latter 
> than the former.

Do you also see that Emacs 23 is significantly faster?

Also, were v24.5 and the current master compiled with the same
compilation options, and similar to Emacs 23?

> Running the profiler on master:
> 
> #+BEGIN
> - term-emulate-terminal 
>   4233  91% 
>  - term-handle-ansi-escape 
>  4065  87% 
>   - term-goto 
>   3965  85% 
>    - term-down 
>    970  20% 
>     - vertical-motion 

Thanks.  I reviewed all the functions that are high on the profile
(term-goto seems to be the main culprit), and didn't see any
significant changes in them since Emacs 23.  Some of them were not
changed at all.  So I'm puzzled how can Emacs 24 and Emacs 25 be
significantly slower only in term.el.  Ideas and suggestions are
welcome.