After 40 days of non-upgrading I came back from a trip and I decided to dist-upgrade my Debian Sid box. Everything went fine but after rebooting I noticed that the temperature was 15°C over its average. There isn't any process eating more CPU than normal but something is clearly going on. Seeing my system monitor applet for Processor load, when the machine is idle, I can see little blue peaks from time to time which I don't remember having them, maybe that could be a clue. Anyway, I cannot see anything strange in my top command output.
So, how can I trace the origin of this heater process?