Checking CPU load per core on a SMP system

So, I got stuck assisting the monitoring team with configuring nagios to monitor our few hundred freeBSD boxes.

I got stuck at the question of "how do we monitor the load on each CPU core?". I know in 7.1 top -P will spit out something similar to what I'm looking for, but sadly we're still on 6-STABLE in most places, and actually still have a few 4.10 boxes kicking around.

So, is there any way to get the CPU usage statistics per core in the 6-STABLE branch?

Thanks for the suggestions, top -S looks like it should do what I need once I wrap it with a sh script.

Systat would work too, but it's less easy than just running grep on "top -S -b" to automate the checking.