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The Hipparch project [Cas94b] uses the Esterel language [Dio95] for describing protocol building blocks. These blocks can be configured to form an application specific protocol implementation. Using application specific knowledge should improve the performance of such an implementation when compared to the use of a standard protocol. However, the C code generated by the currently existing Esterel compiler is not very fast, and moreover has a large code size [Cas94a]. This is a problem the compiler shares with many similar tools that generate executable code starting from a protocol defined in a formal description technique (FDT). This paper describes our design for an optimizer that we incorporated into the Esterel compiler.

After analyzing the code generated by the Esterel compiler, we decided that two optimization techniques merit further investigation:

Thus, the application of both optimization techniques requires information on the execution frequency of the different parts in an Esterel specification. The rest of this paper is structured as follows: Section 2 explains how execution frequencies of different code sections can be calculated from the equivalent Markov model of an Esterel specification. Section 3 demonstrates the use of this approach on an Esterl module implementing the management of the TCP retransmission timer. Section 4 gives our conclusions, and discusses further directions of this work.

Next: Frequency Prediction using Up: No Title Previous: No Title
Wed Aug 9 15:22:05 MET DST 1995