Re: bug-reference-prog-mode slows down CC Mode's scrolling by ~7%

[Alan Mackenzie]

Hello, Eli.

On Mon, Sep 06, 2021 at 22:23:01 +0300, Eli Zaretskii wrote:
> > Date: Mon, 6 Sep 2021 19:08:45 +0000
> > Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > (It is notable that redisplay is quite a bit slower in X at 54 lines
> > than on a Linux console at 65 lines.)

> That's expected: TTY display skips some stuff that is only needed on
> GUI frames, so it's faster.

> > So, based on these timings, I would suggest a new jit-lock-chunk-size of
> > 1500.

> Agreed.  Please be sure to include a reference to this message in the
> commit log message, when you install the change.

> Thanks.

Just as a postscript, the 7% speed advantage from reworked jit code we
were talking about has largely disappeared with the increase in
jit-chunk-size from 500 to 1500.  The speed advantage is now around 1% -
2%, almost, but not quite, lost in the noise.

I therefore propose not installing any of these changes for Emacs-28.  I
don't think the slight speed increase would justify the increased
complexity.

-- 
Alan Mackenzie (Nuremberg, Germany).