bug#56682: Fix the long lines font locking related slowdowns

[Dmitry Gutov]

On 15.08.2022 19:58, Eli Zaretskii wrote:
> > Date: Mon, 15 Aug 2022 19:44:07 +0300
> > Cc: 56682@debbugs.gnu.org, gregory@heytings.org, monnier@iro.umontreal.ca
> > From: Dmitry Gutov <dgutov@yandex.ru>
> >
> > > > Here's the profiler output anyway:
> > > >
> > > >            1067  85% - command-execute
> > > >            1067  85%  - call-interactively
> > > >            1023  82%   - funcall-interactively
> > > >            1012  81%    - end-of-buffer
> > > >            1008  81%     - recenter
> > > >            1008  81%      - jit-lock-function
> > > When did you last resync from Git?  'recenter' got "optimized"
> > > yesterday for buffers with long lines.
> >
> > Just today.
> >
> > In any case, it doesn't look like recenter's problem, since the output
> > says all (or vast majority) of its time is spent in jit-lock-function.
>
> AFAIU 'recenter' shouldn't at all call jit-lock-function in a buffer
> with long lines.  Is this "emacs -Q" without any changes from
> defaults?

It's a buffer without long lines. Simply a large file.

'emacs -Q', yes.