As the design complexity of cyber-physical systems continues to grow, modeling the system at higher abstraction levels with formal models of computation is increasingly appealing since it enables early design verification and analysis. One of the most important aspects in system modeling and analysis is timing. However, it is very challenging to analyze and verify timing at the early design stages, as the design representation is quite abstract and trade-offs have to be made between the performance requirements defined in terms of system functionality and the cost of the feasible architecture that can implement the functionality. In this paper, we present Metronomy, a function-architecture cosimulation framework that integrates functional modeling from Ptolemy and architectural modeling from the MetroII environment via a mapping interface. Metronomy exploits contract theory for timing verification and design space exploration via co-simulation. Two case studies on an electrical power system and a paper-feed sub-system for a high speed printing press demonstrate the effectiveness of our approach.