Jigsaw: A High-Utilization, Interference-Free Job Scheduler for Fat-Tree Clusters

Jobs on HPC clusters can suffer significant performance degradation due to inter-job network interference. Approaches to mitigating this interference primarily focus on reactive routing schemes. A better approach---in that it completely eliminates inter-job interference---is to implement scheduling policies that proactively enforce network isolation for every job. However, existing schedulers that allocate isolated partitions lead to lowered system utilization, which creates a barrier to adoption.