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

[Alan Mackenzie]

Hello, Eli.

On Sat, Sep 04, 2021 at 18:36:32 +0300, Eli Zaretskii wrote:
> > Date: Sat, 4 Sep 2021 15:32:57 +0000
> > From: Alan Mackenzie <acm@muc.de>
> > Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org

> > > Maybe to speed things up, another option is to grow the chunk size
> > > a bit.

> > Maybe.  An advantage of a small chunk size is that fontifying a single
> > screen can be done with a maximum 499 bytes "inefficiency" off the end
> > of a screen.  If we were to increase jit-lock-chunk-size to, say 2000,
> > more of the next screen would be getting fontified, perhaps wastefully.
> > I don't know how important this is.  Maybe I should try it.

> > Indeed.  With jit-lock-chunk-size at 2000, time-scroll on xdisp.c takes:

> > (current code): 16.4s
> > (new proposed code): 16.1s

> > ..  This speed up may well be particular to CC Mode.

> > Let's try jit-lock-chunk-size at 8000:

> > (current code): 15.1s
> > (new proposed code): 15.1s

> > ..  So, yes, it would seem a larger chunk size is advantageous for CC
> > Mode.

> How large (in lines and columns) is your window?  The above numbers
> are only meaningful with the window size.

I'm running in a window with 65 lines and 118 columns.

-- 
Alan Mackenzie (Nuremberg, Germany).