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

[Alan Mackenzie]

Hello, Eli.

On Thu, Dec 03, 2020 at 22:17:33 +0200, Eli Zaretskii wrote:
> > Date: Thu, 3 Dec 2020 18:15:30 +0000
> > From: Alan Mackenzie <acm@muc.de>

> > I've got pretty much up to date copies of both the master and the
> > emacs-27 branches.

> > When I run my customary benchmark (see below) on master's src/xdisp.c in
> > master, it's taking around 34s.  On emacs-27, it's taking 22s.

I forgot to say, I was using the same build of the same CC Mode version
on both.

> Optimized builds or unoptimized ones?

Both optimised builds.

> In unoptimized builds I get almost no difference: Emacs 28 is about 4%
> slower than Emacs 27.  And the profiles look almost identical.

It's strange.  But soon after I posted my post, I couldn't see the slow
34s timing any more.  But other people have concurred with the problem
report.

There's something strange happening.

-- 
Alan Mackenzie (Nuremberg, Germany).