High CPU utilization by systemd-udevd

[gdesilva]

Hi, I am running Ubuntu Studio 10.04 5.0.0-21-lowlatency and have had some issues which appears to be related to the use of Dell USB Bluetooth adaptor.

Upon checking I found out that systemd-udevd sometime consumes over 40% cpu. I have tried various solutions outlined in other forums including stopping and starting systemd-udevd. I noticed that the cpu utilization slowly creeps up after a while.

Would appreciate if anyone has any suggestions.

Thanks

[jeremy31]

Anything show in dmesg log? There might be a udev rule running in a loop

[gdesilva]

@jeremy31, thanks for the response. I did a udevadm monitor and get the following output which appears to be what you suggested. How do I isolate the offending device? I guess I could just not use the BT adaptor but is there a fix for this? Thanks.



$ udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[8014.820106] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8014.944086] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
KERNEL[8015.028121] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
UDEV [8015.028557] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8015.236066] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8015.264019] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
KERNEL[8015.444065] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8015.584147] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
UDEV [8015.584458] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
KERNEL[8015.652086] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8015.860053] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8015.904054] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
KERNEL[8016.068046] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8016.224072] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)
KERNEL[8016.276119] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
UDEV [8016.276569] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8016.484054] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb3/3-0:1.0 (usb)
KERNEL[8016.545061] change /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/usb4/4-0:1.0 (usb)

[Autodave]

10.4? Really? That was dead years ago.

[gdesilva]

Sorry, 19.04 - a typo!

[jeremy31]

Post results for
lsusb

[gdesilva]

$ lsusb
Bus 002 Device 004: ID 0480:b207 Toshiba America Inc Canvio Ready
Bus 002 Device 006: ID 046d:c70a Logitech, Inc. MX5000 Cordless Desktop
Bus 002 Device 005: ID 046d:c70e Logitech, Inc. MX1000 Bluetooth Laser Mouse
Bus 002 Device 007: ID 046d:c709 Logitech, Inc. BT Mini-Receiver (HCI mode)
Bus 002 Device 003: ID 046d:0b02 Logitech, Inc. C-UV35 [Bluetooth Mini-Receiver] (HID proxy mode)
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

[jeremy31]

Edit the file /lib/udev/rules.d/97-hid2hci.rules
and comment out


# Logitech devices
KERNEL=="hiddev*", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c70[345abce]|c71[3bc]", \
RUN+="hid2hci --method=logitech-hid --devpath=%p"

Then reboot and see if the bluetooth still works. If that doesn't work change line 3 of that file as described in https://bugzilla.kernel.org/show_bug.cgi?id=199035#c4

[gdesilva]

@jeremy31 - thanks for your suggestion.

However, before I saw your post, I did some tweaks in the /etc/bluetooth/main.conf file - namely, set PairableTimeout = 0 and FastConnectable = true and rebooted and now udevadm monitor does not scroll on with messages and systemd-udevd does not appear at all on the active processes. The reason why I was prompted to set PairableTimeout to 0 was because my bluetooth devices would constantly drop the connection when left to idle for a while which was annoying to say the least. Similar reasoning to set FastConnectable to true as to get the connection re-established after idle I would have to press a few keys to activate the connection - I guess this will increase the power consumption on the devices but it does not drive me crazy!!

I will monitor the situation for a while and if the problem recurs will try out your suggestion.

Many thanks for your help.

[gdesilva]

Strange.....this morning as I mentioned I thought I had fixed the problem. For over 2 hours the system ran without any udev messages and I did not notice any systemd-udevd processes running.

However, just now restarted the system and I am back at square one! Tried commenting out Logitech devices in 97-hid2hci.rules but it made no difference. Tried after removing 97-hid2hci.rules as suggested in one post https://askubuntu.com/questions/1028883/ubuntu-18-04-systemd-udevd-uses-high-cpu-conflict-with-wifi but still no success.

EDIT: did not do any upgrades or system modifications since this morning either....

[gdesilva]

Tried the following;

1. Removed the bluetooth dongle and the devices and used a PS2 keyboard and a USB mouse. udevadm monitor scrolls with a list of messages. systemd-udevd gets up to around 7% cpu (in about 10 minutes)

2. booted using 5.0.0.20-lowlatency (the previous kernel) but no change in udevadm monitor.

From above it appears that the issue is unrelated to bluetooth as I am now not running any bluetooth devices or dongles but related to USB??

[gdesilva]

OK - fixed it!

The problem as I mentioned in one of the earlier posts had nothing to do with the bluetooth adapter or devices but related to a USB3 card I had installed some time ago.

I noticed that the power cable to the USB3 card was not connected properly. All I had to do was to re-seat power cable and all the messages from udevadm monitor went off.

Thanks everyone for the suggestions.