A final time budget proposal is formed in the task Create time budget proposal based on the identified time budget properties and the estimated influence from future functionality. It should be noted that this input information only serves as a guideline for the budgeting process. It is, for instance, sometimes desired to add a margin to a known WCET, in order to provide for more relaxed implementation. However, it could even be the case that the resulting time budget for a certain component is smaller than a WCET property over the same component that was transformed from a lower abstraction level. In such cases, the lower-level solution needs to be reworked to comply with the (new) time budget.
The set of delay constraints in the identified time budget properties cover, in general, only a part of the end-to-end event chain. A major challenge in this task is to assign time budgets to segments for which no time budget properties have been found. Since no information is available, this has to be done based on behavioral models of the concerned components with the help of the developer’s previous experience.
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