Full screen and windowed native linux games stuttering on x/wayland (GNOME 44.5 and 45.3)
Affected version:
- Fedora Linux 38 and 39
- Mutter 44.5 and 45.3
- Wayland (native Q2RTX running per xwayland mode)
- Mesa-git radv 24.1.0-development
- Kernel version 6.6.0-0.rc2.20230921gt42dc8149.221.vanilla.fc38.x86_64 (initial test) &
- Kernel version 6.7.1-250.vanilla.fc39.x86_64 (latest test)
Bug summary:
Full screen and windowed native linux games are running stuttery. The output feels like <15FPS with laggy input response despite the game being reported to run at stable 36 FPS. Tested per free Q2RTX demo
Steps to reproduce
Scenario testing: a,b and c
(a) Tested this with the Q2RTX native linux demo that is about 1GB small and freely available here. The comfortable built-in fps counter, mangohud and mesa hud do show 36 fps but perception wise the demo clearly runs below that. It seems like only about half of the shown fps get actually drawn, resulting in stutter, mouse lag and slow responsiveness in general. It happens in fullscreen and windowed mode no matter what. Vsync on seems to mitigate the stutter. The stutter becomes very clear with vsync off.
(b) I counter checked the issue by running the demo per micro-compositor gamescope. The stutter happens there as well but on the contrary with vsync on. But with vsync off the demo runs smoothly. So gamescope behaves the complete opposite to mutter.
(c) The windows version of Q2RTX on vkd3d seems to run smoothly with vsync on and off. But the game's responsiveness still feels a bit laggy in comparison to W11. Also vsync on sets a fps cap to 30 fps. This doesn't happen in scenario (a) and (b).
Used system is a ryzen 7 cpu and a rx 6650 xt
History of taken measures post issue report
- Downgraded the kernel temporarily to 6.4.4-200.fc38.x86_64 - issue persists!
- Upgraded to fedora 39 and gnome 45 - issue persists!