Implementation of Directing for Compiled Programs

Debugging and performance measurement tools are becoming increasingly important , especially in distributed and parallel computer systems. These tools are complex, because they are dependent on all major components of computer systems: computer architectures, operating systems, networking, and existing programming tools. The complexity is compounded by the heterogeneous nature of most computing environments. This complexity results in tools that are usually system speciic. Signiicant resources are spent on reimplementing similar tools on diierent systems. A system independent platform for building debuggers and performance measurement tools would simplify the tool construction. This would redirect resources toward building better tools, capable of operating in heterogeneous environments. A characteristic task of debuggers and performance measurement tools is directing. Directing consists of two major classes of activities, monitoring and controlling. Monitoring is used for collecting information about the program behavior. Controlling is used to modify the program state in order to innuence its future behavior. This report describes an implementation of a common directing platform, which provides basic monitoring and controlling primitives. The platform supports directing of compiled programs in distributed and heterogeneous environments. It is integrated with existing programming tools and uses a few generic operating system and networking primi-tives. The platform, called Dynascope, has been realized on two diierent systems. The report presents experiences with both implementations and comparative performance measurements. Novel applications can be built on top of the directing platform. Three such applications, concurrent program testing, event buuering and reverse execution, are described at the end.