Re: Reliable after-change-functions (via: Using incremental parsing in Emacs)

[Alan Mackenzie]

Hello, Dmitry.

On Wed, Apr 01, 2020 at 18:22:00 +0300, Dmitry Gutov wrote:
> On 01.04.2020 16:52, Alan Mackenzie wrote:
> > This doesn't seem to affect starting up performance that badly.  On my
> > machine (a 3 yo AMD Ryzen) visiting xdisp.c (including the fontification
> > of the first screenful of comments) is taking 0.18s.

> Interesting. How do you measure it exactly? Do you kill the buffer 
> between tries?

Using my macro time-it, I did:

(time-it (find-file "..../src/xdisp.c") (sit-for 0))

.  I think this was without the file yet being in the OS's file cache.
Mind you, I have an nvme SSD.

> I have a fast Intel CPU that is barely 2 years old (i9-8950HK), 
> system-configuration-options is "--with-x-toolkit=gtk3 'CFLAGS=-Og 
> -g3'", the build is from emacs-27 branch, recent revision.

That's a debugging build, isn't it?  That probably explains the
difference.

> With 'emacs -Q' it's a little faster, but still

>    (benchmark 1 '(progn (find-file "src/xdisp.c")))

> prints out

>    Elapsed time: 0.968598s (0.144805s in 8 GCs)

Is that also measuring the time for redisplay?

-- 
Alan Mackenzie (Nuremberg, Germany).