Result-Oriented Modeling—A Novel Technique for Fast and Accurate TLM

Abstract

Efficient communication modeling is a critical task in system-on-chip design and exploration. In particular, fast and accurate communication is needed to predict the performance of a system. Recently, transaction level modeling is used to speed up communication simulation at the cost of accuracy. This paper proposes a novel modeling technique, called result-oriented modeling (ROM), which removes the inaccuracy drawback of transaction level models (TLMs) in many cases. Using ROM, simulation models yield nearly the same speed as their traditional TLM counterparts, yet are still 100% accurate in timing. ROM utilizes the fact that internal states in the communication channel are not observable by the caller. Hence, ROM omits the internal states entirely and optimistically predicts the end result. Retroactively, the outcome of the prediction is checked, and if necessary, corrective measures are taken to maintain the accuracy of the model. We have applied the ROM concept to two examples: the industry standard AMBA AHB and the controller area network. To validate the proposed ROM approach, we have analyzed the models in detail for performance and accuracy. Our experimental results show the clear advantages of the ROM concept. For both bus systems, ROM achieves 100% accuracy and highest speeds. In essence, ROM eliminates the TLM tradeoff for a wide range of platforms. It frees the system designer from having multiple models for different purposes and extends the TLM idea to applications that require timing accurate simulation, such as real-time communication.