Re: Time to merge scratch/correct-warning-pos into master, perhaps?

[Eli Zaretskii]

> Date: Sun, 16 Jan 2022 14:45:28 +0000
> Cc: larsi@gnus.org, emacs-devel@gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> > Are you saying that the measured slowdown is specific to the
> > byte-compiler, and will not affect other uses of Lisp, or affect them
> > much less heavily?
> 
> Yes.  The byte compile, as expected, is more slowed down than other
> software.  On a quick measurement of compiling comp.el, I found a
> slowdown of around 12%

That seems to be inconsistent with the 17% slowdown compiling the *.el
files that Lars measured.

> > Because the byte-compiler is  just another Lisp program, it doesn't in
> > general do anything an arbitrary Lisp program won't do.
> 
> It does.  It runs with symbols with position activated, so any operation
> involving an EQ which doesn't match is going to be significantly slower.

But EQ is not specific to the byte-compiler, is it?

> > Can you show a profile where this could be seen quantitatively?
> 
> I'm not sure I understand.  The slowdown in the byte compiler is
> distributed throughout the Emacs C Code.  It doesn't happen at any
> particular isolated place.

I thought the slowdown was in Lisp somewhere.  If it's in EQ, I'm not
sure I understand how come the byte-compiler's slowdown is so much
more significant than in other Lisp code.