Re: window-scroll-functions and performance

[Thierry Volpiatto <thierry.volpiatto@gmail.com>]

Antoine Levitt <antoine.levitt@gmail.com> writes:

> 15/08/11 22:28, Eli Zaretskii
>>> From: Antoine Levitt <antoine.levitt@gmail.com>
>>> Date: Mon, 15 Aug 2011 21:48:00 +0200
>>> 
>>> I'm trying to track down the cause of performance issues in erc. One
>>> problem is with erc-scroll-to-bottom. Here's a simple test: emacs -Q,
>>> M-x erc, accept the default, M-x erc-scrolltobottom-mode, C-l to force
>>> scrolltobottom to act, M-x elp-instrument-package erc, press and
>>> maintain "a" for a while, then M-x elp-results. erc-scrolltobottom gets
>>> called a lot, and that causes noticeable slowdowns: display doesn't keep
>>> up with input, and CPU consumption jumps. This gets my emacs to 100% CPU
>>> just inserting text.
>>
>> Does the problem go away if you turn bidi-display-reordering off?
>
> Nope. (though it does reduce CPU usage a bit - from 100% to 85 here)
>
>> Does it go away if you use Emacs 23.3?
>
> No, it's not a new bug.
>
>> If the answer to any of these 2 questions is YES, please try to come
>> up with a reproducible test case that doesn't involve erc, and I will
>> take a look.
>
> There does not seem to be many people using ERC on this list, and
> consequently not a lot of work on it, it's a shame.

Similar to this, scrolling in org buffers is actually very slow
(impossible to use) unless all headers are open.
Turning off bidi solve problem:
(add-hook 'org-mode-hook #'(lambda () (setq bidi-display-reordering
nil)))

-- 
A+ Thierry
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