Disclosed is an apparatus, method, and program product for observing the nodal workload balance of the system on an ongoing basis, and for dynamically changing the preferred nodes of existing threads in order to improve nodal balance. Workload balance is ascertained on a nodal basis and then thread-based workload information is collected. If the detected imbalance persists, the thread-based information is used to change the assignment of preferred nodes to threads to improve nodal workload balance.