I've seen this question here (and elsewhere), but it doesn't really answer the question I'm trying to answer.
I already know how many cores/CPUs are physically assigned to SQL Server. However, I want to know how many of those cores are, at peak, REALLY being used (ideally, I'd love to know percentiles, utilization %s per core, etc., but I'll take what I can get).
We'd like to migrate this instance to another machine and if we can reduce the number of cores assigned that could free up some core licensing for us. However, I don't want to "downsize" only to find out that our new SQL box falls over because it really needed those extra cores. We will be doing load testing, but the more info. we have around this, the better.
EDIT: I ended up just setting up some dashboard software which makes it easy to see/break out CPU usage (could have used PerfMon).