RevPi connect 4 CPU Usage

[underhood]

Hello all,

just managed to get to the RevPi Connect 4 WLAN | 8 GB | 32 GB after I bought it few weeks ago to be the main home automation controller. Connected it with one RevPi DIO on the right side to do some bench tests. Configured it and am able to read inputs and outputs from command line.

Then I noticed it has quite high CPU usage doing nothing (WiFi off, ethernet on)

Code: Select all

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                                              
     90 root     -51   0       0      0      0 S  29.9   0.0  27:04.86 irq/51-xhci_hcd                                                                      
    204 root     -55   0       0      0      0 D  21.9   0.0  19:35.95 piControl I/O    

also it is quite warm although far from hot. Is this expected to be happening at idle (without any real control process running, just default OS)?

in the configuration web i have disabled Wlan, Bluetooth, log to tmpfs, GUI off, all services in services tab disabled.
SSH and time sync is enabled and only pictory is running.

[nicolaiB]

Hi underhood,

The high cpu load with the xhci (usb controller) is related to a bug in the driver. We fixed this in the mainline Linux kernel and it should be gone with the latest updates. Therefore please check if all updates have been installed.

Nicolai

[underhood]

Thanks a lot,

`apt update && apt upgrade && reboot` did indeed help with the `xhci` process. Also it seems that the heat generated by the controller went down considerably.

Now is there anything that can be done with the `picontrol`? Quick search led me to https://github.com/RevolutionPi/piControl/tree/master which suggests it is a kernel driver which is updating the `/dev/piControl0`.
Is it actually polling for the state of IOs at certain frequency? If so what is it and can it be reduced in situation like home automation?

[p.rosenberger]

Hi underhood,

if you don't use any extension modules (DIO, AIO, ...) and you don't use any revpi specific tooling (revpimodio2, Node-RED-RevPi-Nodes, ...) you can disable the piControl kernel module:

In /etc/modules should be an entry for piControl. You can remove or comment this entry out. But this disables some functionality (see above).

Best regards
Philipp