An MPI tool for automatically discovering the switch level topologies of Ethernet clusters

We present an MPI topology discovery tool for homogeneous Ethernet switched clusters. Unlike existing Ethernet topology discovery methods that rely on simple network management protocol (SNMP) queries to obtain the topology information, our tool infers the topology from end-to- end measurements. The tool works on clusters connected by managed and/or unmanaged Ethernet switches, and does not require any special privilege. We discuss the theoretical foundation of the tool, present the algorithms used, and report our evaluation of the tool.