Design space exploration (DSE) of cyber-physical production systems (CPPS) is a search problem in the space of potential compositional configurations. Current design methodologies follow the separated design paradigm in which the architecture, control, and scheduling are separately designed. Optimization of each part considers only the corresponding goals of interest and overlooks other aspects by adopting gross assumptions, which makes it difficult to determine the global optimal solution for a given system. To address this problem, we propose a codesign method that considers the design spaces of architecture, control and scheduling as monolithic, mixed discrete-continuous spaces. We formulate DSE as an optimization problem and propose a generic iterative algorithm scheme involving simulation in-the-loop to solve the above new problem. To illustrate the effectiveness of the proposed method, a real single-stage reducer CPPS is considered. The design results demonstrate that our method provides better solutions than does the separated design method.