Dispatching Equal-Length Jobs to Parallel Machines to Maximize Throughput
We consider online, nonpreemptive scheduling of equal-length jobs on parallel machines. Jobs have arbitrary release times and deadlines and a scheduler’s goal is to maximize the number of completed jobs (Pm | r j ,p j = p | ∑ 1 − U j ). This problem has been previously studied under two distinct models. In the first, a scheduler must provide immediate notification to a released job as to whether it is accepted into the system. In a stricter model, a scheduler must provide an immediate decision for an accepted job, selecting both the time interval and machine on which it will run. We examine an intermediate model in which a scheduler immediately dispatches an accepted job to a machine, but without committing it to a specific time interval. We present a natural algorithm that is optimally competitive for m = 2. For the special case of unit-length jobs, it achieves competitive ratios for m ≥ 2 that are strictly better than lower bounds for the immediate decision model.
KeywordsDecision Model Parallel Machine Competitive Ratio Deterministic Algorithm Online Schedule
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- 12.Goldwasser, M.H., Pedigo, M.: Online nonpreemptive scheduling of equal-length jobs on two identical machines. ACM Trans. on Algorithms 5(1), 18, Article 2 (2008)Google Scholar