SEH: Size Estimate Hedging for Single-Server Queues

For a single server system, Shortest Remaining Processing Time (SRPT) is an optimal size-based policy. In this paper, we discuss scheduling single-server system when exact information about the jobs' processing times not available. When SRPT policy uses estimated times, underestimation of large jobs can significantly degrade performance. We propose simple heuristic, Size Estimate Hedging (SEH), that only for decisions. A job's priority increased dynamically according to rule until it determined underestimated, at which time frozen. Numerical results suggest SEH has desirable performance estimation error variance consistent with what seen in practice.