SUMMARY I have weird stuttering on force lowest latency on wayland. This does not happen on X11 This does not happen when i have Show FPS effect enabled STEPS TO REPRODUCE 1. Start Wayland session 2. Select force lowest latency 3. Move settings window 4. Go to effects and enable Show FPS effect 5. Try to move settings window again OBSERVED RESULT Weird stuttering (dropped frames?) No stuttering after Show FPS effect enabled EXPECTED RESULT No stuttering SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.22.4 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.2 Kernel Version: 5.13.12-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i7-4790K CPU @ 4.00GHz Memory: 15.5 GiB of RAM Graphics Processor: Mesa DRI Intel® HD Graphics 4600 ADDITIONAL INFORMATION I have 2 monitors Happens with 5.22.4 too Built from master today: kdecoration-git 5.22.80_r268.g1dabf57-1 kwayland-git 5.86.0_r1106.g41bed39-1 kwayland-server-git v5.21.90.r46.g671d70dc-1 kwin-git 5.22.80_r19807.g17b161213-1 plasma-wayland-protocols-git r1028.8d33090-1
I did more research. 1. Start Firefox wayland (MOZ_ENABLE_WAYLAND=1 firefox-developer-edition) 2. Open this page: https://webglsamples.org/aquarium/aquarium.html 3. It shows 30 FPS 4. Enable "Show FPS" effect 5. This page now shows 60 FPS 6. Disable effect 7. It drops back to 30 FPS Operating System: Arch Linux KDE Plasma Version: 5.23.3 KDE Frameworks Version: 5.88.0 Qt Version: 5.15.2 Kernel Version: 5.15.4-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i7-4790K CPU @ 4.00GHz Memory: 15.5 GiB of RAM Graphics Processor: Mesa DRI Intel® HD Graphics 4600
I cannot reproduce at all, I'd say it might be that it got fixed as it all has changed a lot over time. Note having higher fps when the effect is on, could just mean that firefox doesn't request issuing frames that often.