For a while now, I get unusual activity, which comes in bursts of about 1.5 seconds. I can see the activity on XFCE's CPU graph. The intervals are not constant. Sometimes the peak is just milliseconds, sometimes it's occupying nearly the entire (1.5s) interval.
Things I tried:
First suspicion was was logically Firefox (my apoligies). For a couple of days, this seems actually quite sure (according to 'top', Firefox was occupying 50% on 4 CPUs, and that activity was very correlated with the peaks. Until it wasn't... I'd stopped
firefox(checked absence of any process related, like
Webextensions). But suddenly the peaks re-appeared.
Most activity was now by Window manager tasks like
orage(which I also disabled - no luck).
Checked if somehow memory swapping was enabled.
Topdid not indicate any change of Swap use.
GIMP is a fairly reliable trigger for the CPU activity, but load continues much after closing GIMP. Strange: After load stops, closing GIMP also retriggers load.
Suspecting I/O activity could be involved I downloaded
iotopbut couldn't find any real relationship between loads and I/O activity.
Task managershows more or less the same tasks as
topbut each with less CPU occupation.
Though this has been going on for a while, CPU activity is now frequently interfering with typing.
Questions: Is there any way to get more fine-grained load info for each task? Or any suggestion for other experiments?
The machine is an AMD A10-7860K Radeon R7, 8GB RAM Linux 4.19.25.