. In this paper we explore the performance of various aspects of gang scheduling designs. We developed an event-driven simulator of a vanilla gang scheduler that relies on the Distributed Hierarchical Control (DHC) structure. We also developed three variations of the vanilla gang scheduler that rely on a push-down heuristic and on two job-migration schemes to decrease response times by reducing processor idle time. We evaluated the gang schedulers on a compiled, one-month long history of jobs from the Cornell Theory Center that was scheduled by EASY-LL, a particular version of LoadLeveler with backfilling. Our results demonstrate the significant performance improvements that can be achieved with gang scheduling. They also show the performance impact of various aspects in the design of gang schedulers. We identify and discuss the potential benefits of several approaches for addressing a number of gang scheduling issues that, under certain workload conditions, become important in practic...