Data flow graphs granularity for overhead reduction within a PE in multiprocessor systems

The authors propose a method to implement Acyclic Data Flow Graphs (ADFG) in any general purpose multiprocessor system supporting a CSP type language. The granularity of ADFG nodes is discussed During ADFG analysis the authors use fine granularity to exploit all the parallelism inherent in the problem. When the graph G has been allocated, it is divided into P subgraphs G_k (P is the number of the processors in the network); each of them is assigned to a processor P _k. G_k still presents some parallelism which cannot be usefully exploited and which implies a certain amount of overhead during G_k execution; the authors reduce this overhead by executing a post allocation analysis which increases the granularity of G_k nodes. In order to evaluate GTP performances the Overhead Reduction Ratio (ORR) is introduced. ORR is computed by using the results of several executions of GTP on randomly generated ADFG; the presented tests show the effectiveness of GTP