Re: macOS metal rendering engine in mac port

[Alan Third]

On Sat, May 22, 2021 at 11:59:43AM -0700, Aaron Jensen wrote:
> On Sat, May 22, 2021 at 11:45 AM Alan Third <alan@idiocy.org> wrote:
> >
> > On my machine the scroll benchmark shows Emacs 27 being able to update
> > the screen more than twice as fast as any version of the Mac port, yet
> > this shows Emacs 27 isn't really any better.
> 
> For some reason, Emacs Mac port (non-metal) doesn't paint the screen
> during scroll-up-benchmark, it just pauses, but it's faster on my
> machine.

Well, I'm sure we can make that optimisation on the NS port too. ;)

> Full screen frame, with line numbers (11k lines):
> 
> Mac port: 2.88s
> emacs27-drawing branch: 4.42s
> master: 6.75s
> 
> Full screen frame, no line numbers (11k lines):
> 
> Mac port 2.24s
> emacs27-drawing branch: 3.13s
> master: 5.3s

How can the Mac port only see a change of 0.6s while the NS port sees
a change of 1.3s, when the only change is turning line numbers on or
off? Line numbers performance should surely be mostly independent of
the UI toolkit?

You know, my benchmarking is all over the place. I literally just did
two runs at 11s and another two at 8.6s. Nothing changed. And I
regularly see a code change produce an improvement, then undoing the
change retaining the improvement. It's like rebuilding the exact same
code base produces a completely different performance result.

I suspect my Mac rides the CPU frequency continuously or something.
-- 
Alan Third