Request sequencing: Enabling workflow for efficient problem solving in GridSolve

GridSolve employs a standard RPC-based model for solving computational problems. There are two deficiencies associated with this model when a computational problem essentially forms a workflow consisting of a set of tasks, among which there exist data dependencies. First, intermediate results are passed among tasks going through the client, resulting in additional data transport between the client and the servers, which is pure overhead. Second, since the execution of each individual task is a separate RPC session, it is difficult to exploit the potential parallelism among tasks. This paper presents a request sequencing technique that eliminates those limitations and solves the above problems. The core features of this work include automatic DAG construction and data dependency analysis, direct inter-server data transfer, and the capability of parallel task execution.