Re: emacs rendering comparisson between emacs23 and emacs26.3

[Eli Zaretskii]

> Cc: address@hidden, address@hidden, address@hidden, address@hidden
> From: martin rudalics <address@hidden>
> Date: Mon, 6 Apr 2020 11:05:11 +0200
> 
>  >> Do you at least see CPU activity significantly go up when you do such
>  >> mouse wheel scrolling?
>  >
>  > With what build?  With the -O0 build with --enable-checking, I don't
>  > need the mouse: it's enough to lean on C-v and let the keyboard
>  > auto-repeat do its job -- one execution unit of the CPU maxes out
>  > after 5 to 10 C-v's.
> 
> OK.  Then people see the problem and it's just that they do not build
> with -O0.

I build with -O0 all the time, it's just that, like you, I never use
such a build for any serious work, only for debugging and exploring of
new features.

> As long as we are not there (and IMO even after that) Emacs should be
> able to do its SMIE parsing in a practical way: Restrict backward and
> forward parsing to the smallest reasonable code fragment around point.
> And reasonable would mean the smallest enclosing fragment delimited by
> two parens in column zero it can find in either direction (which can be
> still quite large when viewing functions like redisplay_internal).

That's for the major modes to implement, the jit-lock infrastructure
calls the fontification functions on a small region around the area of
interest of the display engine.