For posterity, this was closed by feature/noverlay being merged:
https://lists.gnu.org/archive/html/emacs-devel/2022-10/msg02166.html
> From: Ihor Radchenko
> Cc: Eli Zaretskii , 35...@debbugs.gnu.org
> Date: Sat, 29 Oct 2022 09:02:31 +
>
> Ihor Radchenko writes:
>
> >> There are no intervals in this story. The way overlays are
> >> implemented, they don't use intervals (if by that you mean the
> >> facilities in interv
Ihor Radchenko writes:
>> There are no intervals in this story. The way overlays are
>> implemented, they don't use intervals (if by that you mean the
>> facilities in intervals.c). Someone was working on making overlays
>> more efficient by changing the low-level implementation details, but
>>
> There are no intervals in this story. The way overlays are
> implemented, they don't use intervals (if by that you mean the
> facilities in intervals.c). Someone was working on making overlays
> more efficient by changing the low-level implementation details, but
> that work is yet unfinished.
> From: Ihor Radchenko
> Cc: 35...@debbugs.gnu.org
> Date: Sun, 05 May 2019 09:05:46 +0800
>
> > Of course, if someone comes up with ideas how to speed up
> > vertical-motion without changing what Org does with overlays and/or
> > how overlays are implemented, such ideas will be most welcom
Not sure why, but my reply did not show up in the mailing list. Resending.
> I'm not sure I understand: is your problem with vertical-motion, or in
> general with moving by lines in that file's buffer?
The problem is actually more general. I had a poor performance on line
motion, re-searc
