Re: The Emacs master is much slower than the emacs-27 branch.

[Gregory Heytings]

> > Indeed with CFLAGS='-Og -g3', on my computer (Debian GNU/Linux, GCC 
> > 10.2.0) with 28.0.50 this benchmark takes 25.2 seconds, whereas with 
> > 27.1.50 it takes 67.6 seconds.
> >
> > I bisected this, and the origin of the regression is commit 
> > 365dad197bac5deec9244fd9c189d23c46c99b31, which changes the default to 
> > "use 'static' instead of 'extern inline' [in C headers] because 
> > 'static' typically has better performance for Emacs".  With -Og or -O0, 
> > the benchmark takes 67 seconds, with -O1 or above (-O2 is the default) 
> > it takes 25 seconds.
>
> Thanks, then I think there''s no issue here, and we can stop wondering 
> about the difference in performance.

There's no issue indeed, but it might make sense to merge commit 
b9b32074cecb0e0d20cf527eadacbb0b7f5cced9 into emacs-27.