The Distributed Hardware Monitor ZM4 and its Interface to MEMSY

Computers, especially parallel and distributed systems, are highly complex. Even more complex a task is programming such systems in order to get them run correctly and efficiently. This is due to the manyfold interactions between the processes running at the same time while carrying out a common task. Monitoring is a valuable technique to analyze and understand the dynamic behavior of parallel and distributed software. We prefer hybrid monitoring, a technique which combines advantages of both software monitoring and hardware monitoring.The paper contains a description of a hardware monitor ZM4 which makes our concepts available to programmers, assisting them in debugging and tuning of their code. This is followed by a short survey of the interfaces between ZM4 and a variety of object systems, which make the ZM4 a universal monitor system. Finally, the interfacing to MEMSY is described as the result of a fruitful cooperation between the hardware, software and performance evaluation group in the project.