Princess will put $10.00 per person, per day on your shipboard account unless you tell them not to. That amount is intended to provide the guideline gratuities to all personnel that would typically be tipped by a passenger.
PC dining was one of the reasons they switched to the automatic pooled tipping -- so you wouldn't have to worry about all the different waiters. If you feel you got extraordinary service from a particular waiter, you can tip them personally above and beyond the automatic gratuities; but in theory, that money is supposed to get pooled as well -- however nobody knows for sure if it all does, it varies greatly depending on the staff.