Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for connecting processors using twisted torus configurations. In some implementations, a cluster of processing nodes is coupled using a reconfigurable interconnect fabric. The system determines a number of processing nodes to allocate as a network within the cluster and a topology for the network. The system selects an interconnection scheme for the network, where the interconnection scheme is selected from a group that includes at least a torus interconnection scheme and a twisted torus interconnection scheme. The system allocates the determined number of processing nodes of the cluster in the determined topology, sets the reconfigurable interconnect fabric to provide the selected interconnection scheme for the processing nodes in the network, and provides access to the network for performing a computing task.