Despite our optimistic title of the previous project "FAT: Fast and Accurate TLM
", we analyzed TLMs for many different bus systems and quantified the TLM trade-off between speed and accuracy. A model is either fast or accurate for the general case (although there are cases where a TLM is accurate enough).
Now, we introduced ROM: Result Oriented Modeling, ROM principle, optimistic prediction, check for disturbing influence and prediction update.a modeling technique communication TLMs. ROM can eliminate the inaccuracies for TLM in many cases, yet it is able to retain the TLM speed advantage. ROM makes the assumption that an application only needs to observe the timing at a transaction boundary. On the other hand, everything inside the transaction is hidden.
With this assumption, ROM can rearrange or omit internal states to gain speed. Instead of simulating each bus cycle, ROM makes and optimistic prediction right at the beginning of the transaction. It uses calculates the transaction duration (Answering: How long will this transaction take, if there is no further preemption?). Then, at the end of the predicted time, it checks weather the assumptions did hold true. It updates the prediction, in case there was an unexpected preemption. With that ROM reaches both: speed and accuracy.