/var/log/Xorg.0.log has
(EE) event2  - Logitech USB Keyboard: client bug: event processing lagging behind by 11ms, your system is too slow

So my keyboard is faster than my CPU, and it is an error, not even a warning?

See also https://forums.gentoo.org/viewtopic-t-1117556-start-0.html .

Hello,

i don't know libinput10 is responsible for this behaviour,
but my system does indeed lag noticeabily, both mouse and keyboard as the screen,
but since the behaviour is the same

setup:
* laptop + two different screens via dockingstation
* bumblebee with intel and nvidia

hth, suggestions welcome

more info:
$ xrandr
Screen 0: minimum 8 x 8, current 4740 x 1600, maximum 32767 x 32767
eDP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 340mm x 190mm
   3840x2160     60.00*+  40.00
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
HDMI3 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 0mm x 0mm
   VIRTUAL1.542-1920x1080  60.00*
   VIRTUAL1.543-1920x1080  59.94
   VIRTUAL1.544-1920x1080  50.00
   VIRTUAL1.545-1680x1050  59.95
   VIRTUAL1.546-1600x900  60.00
   VIRTUAL1.547-1440x900  59.89
   VIRTUAL1.548-1280x1024  60.02
   VIRTUAL1.549-1280x800  59.81
   VIRTUAL1.550-1280x720  60.00
   VIRTUAL1.551-1280x720  59.94
   VIRTUAL1.552-1280x720  50.00
   VIRTUAL1.553-1024x768  60.00
   VIRTUAL1.554-800x600  60.32
   VIRTUAL1.555-720x576  50.00
   VIRTUAL1.556-720x480  59.94
   VIRTUAL1.557-640x480  59.94
   VIRTUAL1.558-640x480  59.93
VIRTUAL2 connected 900x1600+3840+0 left (normal left inverted right x axis y axis) 0mm x 0mm
   VIRTUAL2.560-1600x900  59.98*
   VIRTUAL1.546-1600x900  60.00
   VIRTUAL2.561-1280x1024  75.02
   VIRTUAL1.548-1280x1024  60.02
   VIRTUAL2.562-1152x864  75.00
   VIRTUAL2.563-1024x768  75.03
   VIRTUAL1.553-1024x768  60.00
   VIRTUAL2.564-800x600  75.00
   VIRTUAL1.554-800x600  60.32
   VIRTUAL2.565-640x480  75.00
   VIRTUAL1.557-640x480  59.94

$ lspci -nn | grep -i vga
00:02.0 VGA compatible controller [0300]: Intel Corporation CoffeeLake-H GT2 [UHD Graphics 630] [8086:3e9b] (rev 02)
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation TU117GLM [Quadro T2000 Mobile / Max-Q] [10de:1fb8] (rev a1)

$ lshw -C Display
  *-display
       description: VGA compatible controller
       product: TU117GLM [Quadro T2000 Mobile / Max-Q]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:209 memory:e5000000-e5ffffff memory:80000000-8fffffff memory:90000000-91ffffff ioport:4000(size=128) memory:e6080000-e60fffff
  *-display
       description: VGA compatible controller
       product: CoffeeLake-H GT2 [UHD Graphics 630]
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 02
       width: 64 bits
       clock: 33MHz
       capabilities: vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:191 memory:e4000000-e4ffffff memory:a0000000-afffffff ioport:5000(size=64) memory:c0000-dffff

$ dpkg -l | grep nouv
ii  libdrm-nouveau2:amd64                                       2.4.104-1                              amd64        Userspace interface to nouveau-specific kernel DRM services -- runtime
ii  xserver-xorg-video-nouveau                                  1:1.0.17-1                             amd64        X.Org X server -- Nouveau display driver

$ dpkg -l | grep nvidia
ii  bumblebee-nvidia                                            3.2.1-27                               amd64        NVIDIA Optimus support using the proprietary NVIDIA driver
ii  glx-alternative-nvidia                                      1.2.0                                  amd64        allows the selection of NVIDIA as GLX provider
ii  libegl-nvidia0:amd64                                        460.91.03-1                            amd64        NVIDIA binary EGL library
ii  libgl1-nvidia-glvnd-glx:amd64                               460.91.03-1                            amd64        NVIDIA binary OpenGL/GLX library (GLVND variant)
ii  libgles-nvidia1:amd64                                       460.91.03-1                            amd64        NVIDIA binary OpenGL|ES 1.x library
ii  libgles-nvidia2:amd64                                       460.91.03-1                            amd64        NVIDIA binary OpenGL|ES 2.x library
ii  libglx-nvidia0:amd64                                        460.91.03-1                            amd64        NVIDIA binary GLX library
ii  libnvidia-cbl:amd64                                         460.91.03-1                            amd64        NVIDIA binary Vulkan ray tracing (cbl) library
ii  libnvidia-cfg1:amd64                                        460.91.03-1                            amd64        NVIDIA binary OpenGL/GLX configuration library
ii  libnvidia-compiler:amd64                                    460.91.03-1                            amd64        NVIDIA runtime compiler library
ii  libnvidia-eglcore:amd64                                     460.91.03-1                            amd64        NVIDIA binary EGL core libraries
ii  libnvidia-encode1:amd64                                     460.91.03-1                            amd64        NVENC Video Encoding runtime library
ii  libnvidia-glcore:amd64                                      460.91.03-1                            amd64        NVIDIA binary OpenGL/GLX core libraries
ii  libnvidia-glvkspirv:amd64                                   460.91.03-1                            amd64        NVIDIA binary Vulkan Spir-V compiler library
ii  libnvidia-ml-dev:amd64                                      11.2.152~11.2.2-3                      amd64        NVIDIA Management Library (NVML) development files
ii  libnvidia-ml1:amd64                                         460.91.03-1                            amd64        NVIDIA Management Library (NVML) runtime library
ii  libnvidia-ptxjitcompiler1:amd64                             460.91.03-1                            amd64        NVIDIA PTX JIT Compiler library
ii  libnvidia-rtcore:amd64                                      460.91.03-1                            amd64        NVIDIA binary Vulkan ray tracing (rtcore) library
ii  nvidia-alternative                                          460.91.03-1                            amd64        allows the selection of NVIDIA as GLX provider
ii  nvidia-cuda-dev:amd64                                       11.2.2-3                               amd64        NVIDIA CUDA development files
ii  nvidia-cuda-gdb                                             11.2.152~11.2.2-3                      amd64        NVIDIA CUDA Debugger (GDB)
ii  nvidia-cuda-mps                                             460.91.03-1                            amd64        NVIDIA CUDA Multi Process Service (MPS)
ii  nvidia-cuda-toolkit                                         11.2.2-3                               amd64        NVIDIA CUDA development toolkit
ii  nvidia-cuda-toolkit-doc                                     11.2.2-3                               all          NVIDIA CUDA and OpenCL documentation
ii  nvidia-cuda-toolkit-gcc                                     11.2.2-3                               amd64        NVIDIA CUDA development toolkit (GCC compatibility)
ii  nvidia-detect                                               460.91.03-1                            amd64        NVIDIA GPU detection utility
ii  nvidia-driver                                               460.91.03-1                            amd64        NVIDIA metapackage
ii  nvidia-driver-bin                                           460.91.03-1                            amd64        NVIDIA driver support binaries
ii  nvidia-driver-libs:amd64                                    460.91.03-1                            amd64        NVIDIA metapackage (OpenGL/GLX/EGL/GLES libraries)
ii  nvidia-egl-common                                           460.91.03-1                            amd64        NVIDIA binary EGL driver - common files
ii  nvidia-egl-icd:amd64                                        460.91.03-1                            amd64        NVIDIA EGL installable client driver (ICD)
ii  nvidia-installer-cleanup                                    20151021+13                            amd64        cleanup after driver installation with the nvidia-installer
ii  nvidia-kernel-common                                        20151021+13                            amd64        NVIDIA binary kernel module support files
ii  nvidia-kernel-dkms                                          460.91.03-1                            amd64        NVIDIA binary kernel module DKMS source
ii  nvidia-kernel-support                                       460.91.03-1                            amd64        NVIDIA binary kernel module support files
ii  nvidia-legacy-check                                         460.91.03-1                            amd64        check for NVIDIA GPUs requiring a legacy driver
ii  nvidia-modprobe                                             460.32.03-1                            amd64        utility to load NVIDIA kernel modules and create device nodes
ii  nvidia-opencl-common                                        460.91.03-1                            amd64        NVIDIA OpenCL driver - common files
ii  nvidia-opencl-dev:amd64                                     11.2.2-3                               amd64        NVIDIA OpenCL development files
ii  nvidia-opencl-icd:amd64                                     460.91.03-1                            amd64        NVIDIA OpenCL installable client driver (ICD)
ii  nvidia-openjdk-8-jre                                        9.+8u292-b10-3~11.2.2-3                amd64        Obsolete OpenJDK Java runtime, for NVIDIA applications
ii  nvidia-persistenced                                         460.32.03-1                            amd64        daemon to maintain persistent software state in the NVIDIA driver
ii  nvidia-primus-vk-common                                     1.6.1-1                                amd64        thin wrapper for the NVIDIA binary Vulkan ICD (common files)
ii  nvidia-primus-vk-wrapper:amd64                              1.6.1-1                                amd64        thin wrapper for using the NVIDIA binary Vulkan ICD with bumblebee
ii  nvidia-profiler                                             11.2.152~11.2.2-3                      amd64        NVIDIA Profiler for CUDA and OpenCL
ii  nvidia-settings                                             460.91.03-1                            amd64        tool for configuring the NVIDIA graphics driver
ii  nvidia-smi                                                  460.91.03-1                            amd64        NVIDIA System Management Interface
ii  nvidia-support                                              20151021+13                            amd64        NVIDIA binary graphics driver support files
ii  nvidia-vdpau-driver:amd64                                   460.91.03-1                            amd64        Video Decode and Presentation API for Unix - NVIDIA driver
ii  nvidia-visual-profiler                                      11.2.152~11.2.2-3                      amd64        NVIDIA Visual Profiler for CUDA and OpenCL
ii  nvidia-vulkan-common                                        460.91.03-1                            amd64        NVIDIA Vulkan driver - common files
ii  nvidia-vulkan-icd:amd64                                     460.91.03-1                            amd64        NVIDIA Vulkan installable client driver (ICD)
ii  nvidia-xconfig                                              460.32.03-1                            amd64        deprecated X configuration tool for non-free NVIDIA drivers
ii  primus-nvidia                                               0~20150328-13                          amd64        NVIDIA Primus support using the proprietary NVIDIA driver
ii  primus-vk-nvidia                                            1.6.1-1                                amd64        NVIDIA Optimus support for Vulkan applications
ii  xserver-xorg-video-nvidia                                   460.91.03-1                            amd64        NVIDIA binary Xorg driver

# dkms status
bbswitch, 0.8, 5.10.0-10-amd64, x86_64: installed
nvidia-current, 460.91.03, 5.10.0-10-amd64, x86_64: installed

# cat /var/log/Xorg.0.log | grep -i WW
[    52.561] xorg-server 2:1.20.11-1+deb11u1 (https://www.debian.org/support)
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    52.571] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[    66.528] (WW) Option "xkb_variant" requires a string value
[    66.528] (WW) Option "xkb_options" requires a string value
[    66.537] (WW) Option "xkb_variant" requires a string value
[    66.537] (WW) Option "xkb_options" requires a string value
(no EE)

$ dpkg -l | grep -i bumbl
ii  bumblebee                                                   3.2.1-27                               amd64        NVIDIA Optimus support for Linux
ii  bumblebee-nvidia                                            3.2.1-27                               amd64        NVIDIA Optimus support using the proprietary NVIDIA driver
ii  nvidia-primus-vk-wrapper:amd64                              1.6.1-1                                amd64        thin wrapper for using the NVIDIA binary Vulkan ICD with bumblebee

# dmesg | grep -i nvidia
[   53.115944] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input36
[   53.115978] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input37
[   53.116004] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input38
[   53.116030] input: HDA NVidia HDMI/DP,pcm=9 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input39
[   53.116057] input: HDA NVidia HDMI/DP,pcm=10 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input40
[   53.116091] input: HDA NVidia HDMI/DP,pcm=11 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card0/input41
[   54.993836] audit: type=1400 audit(1641995625.500:2): apparmor="STATUS" operation="profile_load" profile="unconfined" name="nvidia_modprobe" pid=2696 comm="apparmor_parser"
[   54.993840] audit: type=1400 audit(1641995625.500:3): apparmor="STATUS" operation="profile_load" profile="unconfined" name="nvidia_modprobe//kmod" pid=2696 comm="apparmor_parser"
[   57.893647] nvidia: loading out-of-tree module taints kernel.
[   57.893657] nvidia: module license 'NVIDIA' taints kernel.
[   57.903369] nvidia: module verification failed: signature and/or required key missing - tainting kernel
[   57.955095] nvidia-nvlink: Nvlink Core is being initialized, major device number 237
[   57.955495] nvidia 0000:01:00.0: enabling device (0006 -> 0007)
[   57.955637] nvidia 0000:01:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none
[   58.002152] NVRM: loading NVIDIA UNIX x86_64 Kernel Module  460.91.03  Fri Jul  2 06:04:10 UTC 2021
[   58.719656] nvidia-modeset: Loading NVIDIA Kernel Mode Setting Driver for UNIX platforms  460.91.03  Fri Jul  2 05:43:38 UTC 2021
[ 1323.184265] nvidia_uvm: module uses symbols from proprietary module nvidia, inheriting taint.
[ 1323.188690] nvidia-uvm: Loaded the UVM driver, major device number 235.

example from daemon.log:
bumblebeed[2497]: [ 6557.498556] [ERROR][XORG] (EE) event12 - Chicony HP Business Slim Keyboard: client bug: event processing lagging behind by 37ms, your system is too slow
bumblebeed[2497]: [12041.977007] [WARN][XORG] (WW) Option "xkb_variant" requires a string value
bumblebeed[2497]: [12041.977032] [WARN][XORG] (WW) Option "xkb_options" requires a string value
bumblebeed[2497]: [12042.041339] [WARN][XORG] (WW) Option "xkb_variant" requires a string value
bumblebeed[2497]: [12042.041409] [WARN][XORG] (WW) Option "xkb_options" requires a string value
bumblebeed[2497]: [12042.042333] [ERROR][XORG] (EE) event16 - PixArt HP USB Optical Mouse: client bug: event processing lagging behind by 42ms, your system is too slow
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 31 with keysym 26 (keycode a).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 32 with keysym e9 (keycode b).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 33 with keysym 22 (keycode c).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 34 with keysym 27 (keycode d).
rtkit-daemon[2949]: Supervising 14 threads of 5 processes of 1 users.
rtkit-daemon[2949]: Successfully made thread 18351 of process 8927 owned by '1000' RT at priority 5.
rtkit-daemon[2949]: Supervising 15 threads of 5 processes of 1 users.
rtkit-daemon[2949]: Supervising 15 threads of 5 processes of 1 users.
rtkit-daemon[2949]: Successfully made thread 18352 of process 8927 owned by '1000' RT at priority 5.
rtkit-daemon[2949]: Supervising 16 threads of 5 processes of 1 users.
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 31 with keysym 26 (keycode a).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 32 with keysym e9 (keycode b).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 33 with keysym 22 (keycode c).
gnome-shell[8920]: Window manager warning: Overwriting existing binding of keysym 34 with keysym 27 (keycode d).

$ cpu-info
Packages:
	0: Intel Core i9-9880H
Microarchitectures:
	8x Sky Lake

$ w
 15:56:11 up  1:03,  1 user,  load average: 1,51, 1,69, 1,59

wim schreef op wo 12-01-2022 om 15:57 [+0100]:

this can probably be safely ignored,
as i forgot that cuda was the reason for using this setup,
without cuda processes running the lag or slow respons is gone

hth,
Wim

Control: found -1 1.19.3-1

Same kind of errors on my two machines:

[    86.305] (EE) event5  - PixArt USB Optical Mouse: client bug: event processing lagging behind by 13ms, your system is too slow
[   110.541] (EE) event5  - PixArt USB Optical Mouse: client bug: event processing lagging behind by 16ms, your system is too slow
[...]
[ 20438.855] (EE) event3  - Apple, Inc Apple Keyboard: client bug: event processing lagging behind by 19ms, your system is too slow
[ 22425.372] (EE) event3  - Apple, Inc Apple Keyboard: client bug: event processing lagging behind by 20ms, your system is too slow
[...]

and

[   200.076] (EE) event2  - DELL Dell USB Entry Keyboard: client bug: event processing lagging behind by 11ms, your system is too slow
[  1778.975] (EE) event2  - DELL Dell USB Entry Keyboard: client bug: event processing lagging behind by 14ms, your system is too slow
[...]

This shouldn't be a warning either, not even an info message, since
many systems are apparently affected and this doesn't seem to have
any consequence. So perhaps this is normal, after all. I'm wondering
what "client bug" means here.

which mentions that this is due to the compositor. But I currently
don't use a compositor on any of my machines.

I've reported the bug upstream.