High CPU usage on wayland

[xMAC94x]

I noticed a very high CPU usage on wayland in the range of 20% - 50%.
The CPU spikes appears almost instantly after startup.

I created a flamegraph . Note: it does not matter if the flamegraph was taken in Playback or Cards tab, it looks simillar.
It looks like some GTK hot rendering loop. Maybe something is triggered over and over.
I am using archs: pwvucontrol 0.4.9-1 and as a desktop wayland pinnacle-comp.
Update to 0.5.1-1 and the issue still persists

Interactive link: https://github.com/user-attachments/assets/e5455b1f-308c-4beb-b339-5e1f5bd93942

[xMAC94x]

I did some additional research and fear this issue might be gtk4 related.
At first i suspected the high update rate of pwvucontrol when sound is playing because of the integrated meter.
However, i stripped down the app to bascially have no updates of anything and this high CPU usage was still reproduceable.

Additionally, this also occurs on 1 specific monitor, which is connected via a USB 4 Dock and has the mode:

interface: 'wl_output',                                  version:  4, name: 46
	name: DP-11
	description: Ancor Communications Inc - ASUS PB287Q - DP-11
	x: 1920, y: -1440, scale: 1,
	physical_width: 620 mm, physical_height: 340 mm,
	make: 'Ancor Communications Inc', model: 'ASUS PB287Q',
	subpixel_orientation: unknown, output_transform: normal,
	mode:
		width: 3840 px, height: 2160 px, refresh: 30.000 Hz,
		flags: preferred
	mode:
		width: 2560 px, height: 1440 px, refresh: 60.000 Hz,
		flags: current

ONLY if the pwvucontrol window takes (almost) the full width of this monitor. If I have it only half the width of the monitor (e.g. split apps), the CPU usage is in the low 2%. As soon as I increase the width the CPU spikes. reducing the width to the previous (low) width does NOT fix this high CPU Usage. Fullscreening however does get rid of the spike.

I have a 4k monitor and the behavior is NOT reproduce-able there.

As you can see, this behavior sounds very very weird. I probably have to make a video to prove it to someone, as no-one will believe software can behave that weird... IMO this is way to weird behavior for pwvucontrol beeing the reason of this performance issue. I will probably investigate further with gtk and https://github.com/pinnacle-comp/pinnacle

[Kommynct]

add_tick_callback in volumebox.rs calls peak_meter.set_level() every compositor frame unconditionally. Doesn't happen on x11 because no vsync I think? May be wrong. Haven't tested or checked, just a lead.