I'm running a % Processor Time on _Total (all processors) on my sql server. In perfmon, the graph of the processor will be going along, stop and then continue on, leaving gaps in the line on the graph. I do get an occasional message telling me there was a problem with the "sampling."
I'm wondering if the stop/start behavior is an indicator of some type of performance challenge. These "gaps" in the processor line do correspond to decreased performance but I can't correlate them to anything. If I look at Current Activity/Process info it doesn't look like anything unusual is going on.