I just wanted to post my appreciation for Smoothie Charts. I've been using it for a few months now for my Minecraft community - it's helped a great deal in identifying performance issues by charting realtime feedback of CPU usage.
We run two main physical (dedicated) servers, and using smoothie to see cpu usage by core and also bandwidth usage is a simple, but extremely useful metric, especially when viewed in realtime.
Our charts are fed by a python script supplying json data from the physical machines.
Thanks go out to the Smoothie Charts developers !