Dashboard Chart CPU Multiple servers

Reaching out for help with creating an accurate cpu graph for multiple server comparison.
Formula I was thinking would be to add cpu idle and wait together. But I don’t know how to formulate the combination of those 2 into a single value and then chart for multiple servers. I could get it to work for one server. but not multiple servers.
Any help would greatly be appreciated.

It depends on your data source and how the metrics are collected

Use graphite. What do you mean by “how the metrics are collected”. We use collectd if thats what you mean.