I have a VPS server. At the CPU usage chart I see long periods of 50% CPU usage that are not related to chart of visitors of my site: http://c2n.me/iRJplq. I checked top and most of the time fastcgi dispatcher that call python scripts takes most of the cpu: http://c2n.me/iRJqRD. I suspect that probably other users at the same physical server use resources a lot, is it possible to understand with more details, why processes started to consume more cpu?
Attach strace to the dispatch.fcgi and see where they are spending most of the CPU time (
strace -p PID). You should also enable some tracing/profiling in your Python script to track this (if they have any decent logging features).
It's unlikely your VPS provider is mixing the CPU usage of your virtual machine with that of others in the same physical server.