Scheduling with unit processing and communication times on a ring network: Approximation results
Résumé
We consider the problem of scheduling UET-UCT task graphs on a ring network of m processors, in order to minimize the makespan. We show that no polynomial-time algorithm with relative performance better than 4/3 can exist in that case (unless P=NP), and prove that the relative performance g of the general list scheduling algorithm proposed by Rayward-Smith is such that [radicm]leg lap-1 + 3/8m -1/2m, for m even.