A multi-processor system includes multiple processors arranged in multiple clusters. Different clusters have different power and performance characteristics. The system includes a task scheduler to schedule tasks to the processors. The task scheduler, in response to detection of a scheduling event trigger, is operative to identify a scheduling objective between a first objective of energy optimization and a second objective of load balance. The scheduling objective is identified based on at least respective operating frequencies and loading of all processors in a highest-capacity cluster of the multiple clusters. According to the identified scheduling objective, the task scheduler schedules a given task to a processor selected among the processors in the multiple clusters.