> From: Eval Exec <execvy@gmail.com>
> Date: Sat, 28 Dec 2024 21:31:28 +0800
> Cc: 74813@debbugs.gnu.org
>
> Friendly Pong. I'm busy these days. I will upload a reproducible
> minimal init.el tomorrow.

Did you have time to come up with a reproducible recipe?

>
> On Sat, Dec 28, 2024 at 6:59 PM Eli Zaretskii <eliz@gnu.org> wrote:
> >
> > > Cc: 74813@debbugs.gnu.org
> > > Date: Thu, 12 Dec 2024 11:11:45 +0200
> > > From: Eli Zaretskii <eliz@gnu.org>
> > >
> > > > From: Eval Exec <execvy@gmail.com>
> > > > Date: Thu, 12 Dec 2024 15:59:51 +0800
> > > >
> > > >
> > > > I opened a large rust file, about 5000 lines.
> > > > scroll-up is quick and smooth, no laggy:
> > > > [...]
> > > >
> > > > but scroll down is very laggy:
> > > >
> > > >         2667  87% - command-execute
> > > >         2666  87%  - funcall-interactively
> > > >         2666  87%   - evil-scroll-page-up
> > > >         2666  87%    - scroll-down
> > > >         2665  87%     - apply
> > > >         2664  87%      - ad-Advice-scroll-down
> > >                            ^^^^^^^^^^^^^^^^^^^^^
> > > >         2663  87%       - #<primitive-function scroll-down>
> > >
> > > First, you have an advice on scroll-down.
> > >
> > > Furthermore, scrolling down exposes portions of a file that were never
> > > seen before, which needs to fontify them.  If fontification is
> > > expensive, it is expected that you will see some lags.  What happens
> > > if you scroll down, then go back to the beginning, and then scroll
> > > down again -- is scrolling down the second time much faster?
> > >
> > > Also, you didn't say which major mode did you use for this file.
> >
> > Ping!  Can you please answer my questions?
>