Re: emacs rendering comparisson between emacs23 and emacs26.3

[Eli Zaretskii]

> From: Richard Stallman <address@hidden>
> Cc: address@hidden, address@hidden, address@hidden
> Date: Mon, 30 Mar 2020 22:28:10 -0400
> 
>   > For new features that can be disabled, that is mostly the case
>   > anyway.  But most new features we add don't have such knobs, usually
>   > because we don't envision anyone to want them.
> 
> My point is, if a feature causes significant slowdown, in general usage,
> that in itself is a reason to give it a knob.

When we know a new feature causes significant slowdown, we either fix
it, or provide a way to disable or work around it.  The problem is, we
don't always know there's slowdown, as it frequently happens only in
specific rare use cases.  (John said some time ago we should have a
benchmarking test suite, but I don't think anyone's working on it.)
Also, several slowdowns each of which is minor can together cause a
significant slowdown, and in that case it is even harder to detect and
fix that.