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rc

Member

Registered: 2020-08-21

Posts: 3

High CPU / memory usage in locked/kiosk mode on CentOS-8

XFce 4.14.1 (from EPEL) works nicely on CentOS-8 in the normal, non-locked-down mode.

After much effort, I got "locked" and "kiosk" mode working.  That was an infuriating ordeal before I realized xfconf continues running and preserving old configs even after the user logs-out and I update the configs.  A well-place "pkill xfconf" fixed that issue.

After that, several xfce services were consuming around 50% of a CPU core constantly, and over the course of 4 hours or so locking 8GB of RAM and causing system crashes.  The culprits primarily being: 
xfsettingd, xfconfd, xfce4-panel.  A periodic HUP signal sent to them releases gigabytes of RAM, but isn't much of a fix. 

I traced this further to xfsettingd.  Kill that process after the user logs-in, and the others drop dramatically down significantly to nearly normal levels.  The xfce4-panel process constantly using 6% of CPU while the system is idle certainly seems wasteful and not seen on non-locked/kiosk setups, but still a vast improvement.  I've tested disabling ALL autostart services, but no improvement.

Can anyone shed some light on this issue? Have you seens something similar?  Perhaps a known bug in the version in EPEL?  Or some pointers for debugging and getting some visibility into why these XFce processes are deciding they need to flip out?

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,486

Re: High CPU / memory usage in locked/kiosk mode on CentOS-8

Hello and welcome.

What exact versions of xfsettingd, xfconfd, xfce4-panel are you running?

Here are a couple of debugging links that might be helpful:
- https://wiki.xfce.org/howto/debug
- https://docs.xfce.org/xfce/xfce4-panel/debugging (valgrind would report memory leaks)

You might have found some bugs that would need to be reported.

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rc

Member

Registered: 2020-08-21

Posts: 3

Re: High CPU / memory usage in locked/kiosk mode on CentOS-8

What exact versions of xfsettingd, xfconfd, xfce4-panel are you running?

# xfsettingsd --version
xfsettingsd 4.14.1 (Xfce 4.14)

# /usr/lib64/xfce4/xfconf/xfconfd --version
Xfconfd 4.14.1

xfce4-panel -> Panel -> About
4.14.1

Here are a couple of debugging links that might be helpful:
- https://wiki.xfce.org/howto/debug
- https://docs.xfce.org/xfce/xfce4-panel/debugging (valgrind would report memory leaks)

Thanks for the pointers.

With PANEL_DEBUG=1  I'm getting a super-tight loop of errors from xfsettingsd that it can't set properties on workspace names:

(xfsettingsd:3706): xfconf-WARNING **: 10:02:38.380: Failed to set property "xfwm4::/general/workspace_names": GDBus.Error:org.xfce.Xfconf.Error.PermissionDenied: Permission denied while modifying property "/general/workspace_names" on channel "xfwm4"

Kill xfsettingsd, then I only get a much slower loop every second that it can't set properties on every launcher on the panel. e.g.:

(xfce4-panel:3477): xfconf-WARNING **: 09:56:42.665: Failed to set property "xfce4-panel::/plugins/plugin-1/items": GDBus.Error:org.xfce.Xfconf.Error.PermissionDenied: Permission denied while modifying property "/plugins/plugin-1/items" on channel "xfce4-panel"

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,486

Re: High CPU / memory usage in locked/kiosk mode on CentOS-8

Odd. xfconf is reporting that it can't write some data. What do the following commands return:

ls -al ~/.config/xfce4/xfconf/xfce-perchannel-xml/
xfconf-query -c xfwm4 -lv
xfconf-query -c xfwm4 -p /general/workspace_names
ps -ef | grep $USER | grep xf

Edit: Just re-read and noticed you are running in kiosk mode. If those properties are locked down, xfconf shouldn't be writing to them. That is probably a bug.

Last edited by ToZ (2020-08-25 22:17:17)

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rc

Member

Registered: 2020-08-21

Posts: 3

Re: High CPU / memory usage in locked/kiosk mode on CentOS-8

Thanks. I have submitted this info as a bugreport:

https://gitlab.xfce.org/xfce/xfconf/-/issues/15

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,486

Re: High CPU / memory usage in locked/kiosk mode on CentOS-8

Though I don't think that's the reason for your high CPU. I think something else is going on. Perhaps one of the developers can offer some assistance.

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