This massive speed-up on 4K screens makes me want to try it. The wayland pgtk version has such terrible latency I have to use the X11 build to avoid gnashing teeth during my working hours. And I think it's the X11 version that uses cairo, so the actual speedup in my case might be even larger.

I reported the issue years ago, the pgtk maintainer confirmed, say they can't do much as they're using GTK3 which isn't hardware accelerated, so I have to wait until they migrate to GTK4 (in a decade or so). A bit disappointing, but that's open source.

Looks like I'm not the only one suffering with a 4K screen: https://old.reddit.com/r/emacs/comments/ucv0at/awful_perform...

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andros 7 hours ago | parent | next [-]

Good news on the Wayland front: there is already a working branch (wayland-pgtk-backend) that adds a PGTK binding on top of the same EGL/GLES driver, pending merge to main. If you want to try it before that, the branch is available on the repo.

	▲	zeendo 5 hours ago \| parent [-]
		I can't find that branch here - https://cgit.git.savannah.gnu.org/cgit/emacs.git Am I looking in the wrong place?

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panza 2 hours ago | parent | prev | next [-]

My experience with Emacs, 4K and Wayland was so abysmal that I spent a weekend making my config fully compatible with a terminal.

Not ideal, but I'll keep running it through Ghostty until it's fixed.

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arikrahman 7 hours ago | parent | prev [-]

I didn't notice to much performance issue switching to PGTK on an ultrawide on Niri. Are you using the daemon to render Emacs as a client?

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zeendo 6 hours ago | parent [-]

I have perf issues with emacs-pgtk on a 4k screen on Wayland with Niri in both Emacs as a client and not. The issues appear with typing or scolling, the delay and lag become noticeable.

For me the issue is only unbearable when running fractional scaling, for some reason.

I'm going to try the branch mentioned in the sibling comment, though.

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arikrahman 6 hours ago | parent [-]

I have almost the exact same setup as you and even have strange behavior with fractional scrolling. I'm on NixOS so the setup is even inspectable: https://codeberg.org/arik/dotfiles

After resetting the scale from 1.2 to 1.0 through 'niri msg output HDMI-A-2 scale 1' I actually noticed a performance increase! I will have to troubleshoot this, although you may have stumbled on a great lead toward the root cause.

	▲	green7ea 5 hours ago \| parent \| next [-]
		I'm also on Emacs and Niri, seems to be a popular combo, and I don't have any performance problem. At home I'm driving an Ultrawide (3440x1440@75Hz) at scale 1.1. At work I'm driving two 4k screens at scale 1.2. I might be less sensitive to latency but it could also be a graphics driver issue or something similar. I'm using Arch with emacs-wayland (pgtk) with a strix halo (all AMD) laptop.
	▲	zeendo 5 hours ago \| parent \| prev [-]
		I didn't invent this mitigation FWIW - I saw it mentioned in one or another thread about this by someone else - possibly on the big reddit thread on this topic, not sure.