A Formal Approach to Optimized Parallel Protocol Implementation

We propose a formalized method that allows to automatically derive an optimized implementation from the formal speci cation of a protocol. Our method starts with the SDL speci cation of a protocol stack. We rst derive a data and control ow dependence graph from each SDL process. Then, in order to perform crosslayer optimizations we combine the dependence graphs of di erent SDL processes. Next, we determine the common path through the multi-layer dependence graph. We then parallelize this graph wherever possible which yields a relaxed dependence graph. Based on this relaxed dependence graph we interpret di erent optimization concepts that have been suggested in the literature, in particular lazy messages and combination of data manipulation operations. Together with these interpretations the relaxed dependence graph can be be used as a foundation for a compile-time schedule on a sequential or parallel machine architecture. The formalization we provide allows our method to be embedded in a more comprehensive protocol engineering methodology. Correspondence and o print requests to: S. Leue, e-mail: [email protected], or Ph. Oechslin, e-mail: [email protected] .ch 2 S. Leue and Ph. Oechslin