much of KDE freezes for 20 seconds (includes strace output)

[Hans Ecke]

Hi there-

Ever since I switched from KDE 3.5 (F8) to KDE 4.2 (F10) I have this 
problem:

When: 

* starting a KDE application, for instance konqueror
* opening the start menu
* attempting to add a new event in korganizer

What happens: (example: new konqui instance)

Konqueror appears. By default for me it appears in a blank window. 
However when trying to input anything in the location bar it does not 
take any input. In fact, it does not even redraw itself if I minimize it 
and then restore. It remains frozen like this for about 20 seconds. Then 
everything is normal again.

Once that happens everything is fine for a while (10 minutes or so). New 
konqueror windows come up and are responsive just fine. But if I don't 
do anything for a while the problem reappears.

What happens: (example: new event in korganizer)

I double-click on a time in korganizer. A "New Event" window comes up. 
Similar to the konqueror example, it draws itself completely, but then 
becomes nonresponsive and does not redraw itself. Becomes responsive 
again after about 20 seconds.

What happens: (example: start menu)

I click on the start menu. It appears as a black square with rounded 
corners, obscuring the desktop and windows underneath. In other words, 
different from the examples above it does not draw itself before 
freezing. It unfreezes after 20 seconds.

Speculation:

Some service is failing and KDE takes 20 seconds to notice that or to 
try and start it.

How do I debug that? I attached an strace log, but that is very opaque. 
Scroll down the timestamps and you see the big jump at 07:50:38.674661 
and at 07:50:49.615261. Two select() calls that take 10 and 15 seconds, 
respectively. I guess file descriptor 7 is its connection to DBUS? 

Any help would be appreciated. This is very frustrating.....

Cheers

Hans