Embodiments relate to methods, systems, and computer program products for path management in a processing system. In a method, in response to receiving a request for adding a target controlling unit into a processing system, a plurality of network nodes in the processing system are divided into a group of subnets based on a topology of the plurality of network nodes, the plurality of network nodes being connected to at least one controlling unit in the processing system. A workload estimation is determined, the workload estimation representing a workload to be caused by the target controlling unit to the processing system. A target subnet is selected from the group of subnets for connecting the target controlling unit into the processing system based on the workload estimation. With these embodiments, the target subnet may be selected in an automatic way such that the performance of the processing system may be increased.