Bug 458632

Summary: Error log: libinput of keyboard using Kwin Wayland is slower than Xorg
Product: [Plasma] kwin Reporter: Zesko <zeskotron>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: nate
Priority: NOR    
Version First Reported In: 5.25.4   
Target Milestone: ---   
Platform: Manjaro   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Zesko 2022-09-02 09:43:49 UTC
SUMMARY
***
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I am using the gaming keyboard for workflows and games in KDE Wayland (Manjaro or Arch Linux) without notice any issue.

But I checked the error logs:  `journalctl --no-pager -p err - b`
Here is the output: 

```
Sep 02 08:07:01 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 28ms, your system is too slow
Sep 02 08:22:53 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 34ms, your system is too slow
Sep 02 09:07:54 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 24ms, your system is too slow
Sep 02 09:25:45 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 34ms, your system is too slow
Sep 02 09:40:59 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 22ms, your system is too slow
Sep 02 09:41:09 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 24ms, your system is too slow
Sep 02 09:42:04 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: client bug: event processing lagging behind by 30ms, your system is too slow
Sep 02 09:42:04 zesko kwin_wayland[1467]: kwin_libinput: Libinput: event9  - SONiX Gaming Keyboard: WARNING: log rate limit exceeded (5 msgs per 60min). Discarding future messages.
```
The error messages said "event processing lagging behind by more than 20 ms"

I switch to my other 2 different keyboards, the same error messages appear when using Kwin Wayland.

I switch back to Xorg that does not show this error message or has no issue.

STEPS TO REPRODUCE
1.  Switch to Wayland in login session
2.  Try typing your keyboard normally more than 1 hour
3.  Check the log: `journalctl -b -p err`
4.  See the error "event processing lagging behind by more than 20 ms"

OBSERVED RESULT

kwin wayland libinput is slower than kwin xorg libinput.

EXPECTED RESULT

kwin wayland libinput performance should be improved like Xorg or better than Xorg.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro KDE latest version
(available in About System)
KDE Plasma Version: 5.25.4
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5

ADDITIONAL INFORMATION
WM: kwin_wayland
DM: SDDM
PC: Gaming PC using AMD Ryzen 5800x and Radeon RX 5700 and dual monitors 1440p, 
they are strong enough for game.
Comment 1 Zesko 2022-10-20 11:14:52 UTC
This error message does not appear in the log.

Update from kwin 5.25.5 to 5.26.1 to fix this issue that I guess.