1) The Mutter presumed bug shows up with an NVidia graphics card.  I do
have an old but "highend" system.  While I can test with mesa, mesa has
a 24 FPS performance, so it is also a bad testbed.  You have my system
specs, but here are again:

NVidia 3080 RTX

Two monitors:

- 4K HDR monitor at 200% DPI
- 1 FullHD monitor at 100% DPI

I expect most GNOME50.1 users are using it from a laptop with one
monitor.  The graphics card for them if they do heavy graphics is also
likely NVidia.


2) You said: 

"Please try enabling this toggle:

  Alt+F2 > "lg" > Flags > DISABLE_DIRECT_SCANOUT"

Anwer:  I did and there was no difference (neither better or worse).

* Because the stall persists even when direct scanout is disabled, this
is not a Wayland buffer-starvation issue caused by the compositor
holding onto too many buffers.

* According to AI, this points to a frame-pacing and synchronization
bottleneck between GNOME's Mutter compositor and NVIDIA's EGL
stream/explicit sync implementation. When direct scanout is disabled,
mrv2 is forced to render to an offscreen buffer, which Mutter then
composites onto the screen.

* BTW, I did check explicit sync is being used with WAYLAND_DEBUG=1 to
rule that out too.

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https://bugs.launchpad.net/bugs/2153492

Title:
  Regression in OpenGL Wayland performance (not NVidia issue)

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