A method, apparatus, and computer program product are disclosed in a data processing system for providing a virtualized time base in a logically partitioned data processing system. A time base is determined for each one of multiple processor cores. The time base is used to indicate a current time to one of the processor cores for which the time base is determined. The time bases are synchronized together for the processor cores such that each one of the processor cores includes its own copy of a synchronized time base. For one of the processor cores, a virtualized time base is generated that is different from the synchronized time base but that remains synchronized with at least a portion of the synchronized time base. The processor core utilizes the virtualized time base instead of the synchronized time base for indicating the current time to the processor core. The synchronized time bases and the portion of the virtualized time base remaining in synchronization together.