As of QIDI's latest Plus4 firmware release, 1.6, the USB wireless module included in current machines is using an rtlink dongle that is creating a kernel thread that is consuming considerably more CPU cycles than is expected. Due to the finite compute available on the SOC, it's best to preserve it for klipper.
This can be achieved in by simply removing the dongle from the Plus4 system board or more dramatically disabling the driver module from loading when the printer is booting up.
The easiest way to observe impact is running the top or htop commands from
the command line. If you see RTW_CMD_THREAD and CPU is high, you are impacted. In this screenshot, the user's printer is consuming a considerable amount of CPU at 24.3%
Remove the system fan board cover and examine the USB ports on the side right side of the board. The USB dongle looks like this, but could vary:
Once removed, you need to restart your printer so the module isn't loaded. Until the machine is restarted, the module will remain loaded and continue to needlessly consume CPU cycles.
If you'd rather NOT remove the dongle, you can simply blacklist the module from loading in the first place. To do so, execute this simple one liner to create the this file:
sudo bash -c "echo 'blacklist 8188*' > /etc/modprobe.d/blacklist-8188gu.conf"
Once complete, restart your Plus4.
Once you have restarted your Plus4, connect via ssh to your printer and run the following command:
ps aux|grep -i rtw_cmd_thread && echo 'Module still loaded' || echo 'Module not loaded'