Priorities among multiple queues for processor co-allocation in multicluster systems

In systems consisting of multiple clusters of processors which employ space sharing for scheduling jobs, such as our Distributed ASCI Supercomputer (DAS), co-allocation, i.e., the simultaneous allocation of processors to single jobs in multiple clusters, may be required. In order to handle both single-cluster (local) jobs and multi-cluster (global) jobs, such systems may have only local schedulers (which then need to be aware of the whole system), or only a single global scheduler or both, and each scheduler has its own queue. We assess with simulations the response times of both local and global jobs in multicluster systems for different configurations of queues, for different priority orders in which the associated schedulers are allowed to schedule jobs, and for different job-stream compositions.