HPC Job Mapping over Reconfigurable Wireless Links

Wireless supercomputers and datacenters with 60GHz radio or free-space optics (FSO) have been proposed so that a diverse application workload can be better supported by changing network topologies by swapping the endpoints of wireless links. In this study we proposed the use of such wireless links for the purpose of improving job mapping. We investigated various trade-offs of the number of wireless links, time overhead of wireless link reconfiguration, topology embedding and job sizes. Our simulation results demonstrate that the wired job mapping heavily degrades the system utilization of supercomputers and datacenters under a conventional fixed network topology. By contrast, wireless interconnection networks can have an ideal job mapping by directly reconnecting non-neighboring computing nodes. It improves the system utilization by up to 17.7% for user jobs on a supercomputer and thus can shorten the whole service time especially for dealing with dozens of intensively incoming jobs. Furthermore, we confirmed that either workload or scheduling policy does not impact the fact that the ideal job mapping on wireless supercomputers outperforms that on wired networks in terms of system utilization and whole service time. Finally, our evaluation shows that a constrained and reasonable more use of partial wireless links can achieve shorter queuing length and time.