Optimal loop storage allocation for argument-fetching dataflow machines

Abstract

In this paper, we consider the optimal loop scheduling and minimum storage allocation problems based on the argument-fetching dataflow architecture model. Under the argument-fetching model, the result generated by a node is stored in a unique location which is addressable by its successors. The main contribution of this paper includes: for loops containing no loop-carried dependences, we prove that the problem of allocating minimum storage required to support rate-optimal loop scheduling can be solved in polynomial time. The polynomial time algorithm is based on the fact that the constraint matrix in the formulation is totally unimodular. Since the instruction processing unit of an argument-fetching dataflow architecture is very much like a conventional processor architecture without a program counter, the solution of the optimal loop storage allocation problem for the former will also be useful for the latter.