I updated Qt to 4.5 and rebooted and I saw that KDEed4 or something like that was hogging on my CPU, so I killed it.
Now I noticed that Kwin effects are not working. Is this somehow related?
I use KDEmod4.2.1.
Any ideas what it is and how to repair it are welcome.
(I'll reboot to see if it comes up again)

kded4 is the KDE 4 Daemon, and is responsible for providing cross KDE application services, including Powerdevil, Password caching, SSL and Hotkeys support, etc.

However it should not be using 50% of your CPU, it rarely uses 1% on my system.
Which modules are listed in System Settings > Advanced > Service Manager?

bcooksley wrote:kded4 is the KDE 4 Daemon, and is responsible for providing cross KDE application services, including Powerdevil, Password caching, SSL and Hotkeys support, etc.

However it should not be using 50% of your CPU, it rarely uses 1% on my system.
Which modules are listed in System Settings > Advanced > Service Manager?

It's OK now I guess it was an "one-off" experience.
Now it uses "no CPU at all".
But others using KDEmod and Qt4.5 did experience similar thing.
One reported that he left it running and it came down to normal level.
but why would it even go up to 50 and so pro-cent of CPU??
Anyway this is sort of solved, even though I have no idea what solved it or why it happened.

Usually it is the fault of one of the many modules used in kded4 that causes the issue, but tracking it to an individual module is usually very hard.

Hello,I have an issue with kded4 which uses the 100% of cpu and wich also cannot be killed.It seems to appear after deactivating my 3g connection from knotify4.

Please ensure you are using the latest available version of Network Management, and that all packages are up to date.

After the above, which version of Network Management are you using? (Available from your package manager)

I no longer use KDE as I've switched to a tiling window manager, but I do use a couple KDE apps (mainly kmymoney). I often find instances of knotify4 or kded4 using 100% of my CPU. Is there any way around this?

I used to get that every now and then after having logged out and back in again. My solution was to simply kill the offending processes - never had a problem using that method.

Please mark the topic as solved by using the green hook at the problem solving post.
Thanks.

"Just kill the process" is not a solution.

I thought that it was solved because of the title:
"Re: [SOLVED] Whats Kded4 and why is it using 50% of my CPU?"

If it is not solved then there's no need for marking it but in that case the title should be corrected.

A while back there was an issue with QNTrack and 100% usage in KDE Daemon. Make sure it is up to date.

Dear all,

Since the complaint is so generic
a) it comes up in google searches
b) the answer should be how to diagnose this further.
"Usually it is the fault of one of the many modules used in kded4 that causes the issue, but tracking it to an individual module is usually very hard." is the best answer above, but isn't complete.
I think the link below is better:
http://kdepepo.wordpress.com/2011/05/11 ... ded4-bugs/
but the situation described is pathetic. Almost as bad as Windows. If this is really the best solution, then kded will benefit greatly from some user-friendly debugging handles to further isolate which parts are hogging CPU/memory.