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

[Dmitry Gutov]

Hi Alan,

On 04.04.2020 14:06, Alan Mackenzie wrote:

> > 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))

It might be valuable if you evaluated exactly the same form I did. And 
made sure that the buffer is not visited in advance. And did that in an 
'emacs -Q' session.

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

I do as well. I have a fast laptop, pretty sure it's faster than what 
90% of our users have. My single-threaded performance must be better 
than yours for sure.

> > 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.

Debugging-ish. It hardly explains the 4.5x difference. So we're probably 
measuring different things.