[Interest] Program runs only on four core processors.... sometimes.

[Guido Seifert]

> I'd just like to add the fact that I drove one station too far with
> the train this morning, because I was busy replying to your question.
> Luckily I live in Switzerland where everything is pretty small and
> tiny, such as the distances between train stations, so I could walk
> back ;)

Sorryyyyy.... And greetings from the cold Norway. :-)


> I'd /love/ to have your data source - may I borrow some of your data? ;)

Awwww, come on. There are _rare_ cases where you really have 100% control over your data. 
 
> Another thing that I forgot: while the main process is "freezing",
> what does the CPU utilisation say? Is it high and the process is
> actively "idle" in some loop? Or is it low and the process is just
> "waiting for something"?

As I already posted as response to Thiago's mail, I now think it is resource starvation.
The program is not frozen as I thought. But one button click, which normally takes at max 2-3 seconds with four cores, now seems to take ~15 minutes with only one core. 
 
> Could you remote debug it? Maybe trying to attach with a remote
> debugger (I think that is even possible via some menu entry in e.g. Qt
> Creator) would tell you where the process is currently stuck (but
> you'd probably need to compile with debug info, and that might already
> alter the behaviour again.

Would have done it... though on a virtual machine with one core I doubt it would have been fun. :-/

Fortunately (?) I now have seen, that it is not actually 'stuck'. 

Guido