Emerging parallel or distributed, heterogeneous real-time computer systems with many disparate constraints and requirements would benefit from a unifying and comprehensive systems engineering support in the design, testing and deployment phases, which interfaces with a human at a very high level and efficiently handles the system complexity. We present an approach to integration of (1) a compiler-and Constraint Logic Programming-based approach to design and engineering of real-time systems, and (2) an on-line performance analysis and visualization technology. An example distributed real-time system is used to help describe the integrated approach. Details are presented about how the involved technologies are used to help system developers and users achieve better system performance through on-line repair and reconfiguration.