  Min, Veeravalli, and Barlas have recently proposed strategies to minimize the
overall execution time of one or several divisible loads on a heterogeneous
linear network, using one or more installments. We show on a very simple
example that their approach does not always produce a solution and that, when
it does, the solution is often suboptimal. We also show how to find an optimal
schedule for any instance, once the number of installments per load is given.
Then, we formally state that any optimal schedule has an infinite number of
installments under a linear cost model as the one assumed in the original
papers. Therefore, such a cost model cannot be used to design practical
multi-installment strategies. Finally, through extensive simulations we
confirmed that the best solution is always produced by the linear programming
approach, while solutions of the original papers can be far away from the
optimal.

Distributed, Parallel, and Cluster Computing