What do you alert on for CPU on Linux?

I use both but I do atleast try to focus more on MinLoadPerCore since it's more indicative of the work the server is doing than just raw CPU usage. That being said, it does tend to require individual tuning depending on what that server does, and I don't have a lot of Linux systems to monitor either. If your not familiar with what Load is in linux, I suggest reading up on it. It's not exclusively CPU related and can also account for things like memory and disk latency causing delays in workloads.

I generally would throw together a dashboard with CPU %, Load and such, and review the data for the past week or even month to get a better understanding what is expected. Then set thresholds based on that. I've had some web servers hit 30-40 5min-load (without cpu % not even getting that much higher) and I would want to know about it. But if you wanted to set a baseline of like 1.5-2 across multiple servers, perhaps that may help in your case.