A petri net toolkit for parallel program debugging

An effective debugger must support the language and operating system resource abstractions that are available to the programmer. Earlier debuggers worked at the machine architecture level: they dealt with machine instructions and registers. Current debuggers, designed for single process debugging, permit access to program variables and breakpoints and single-stepping at the level of high-level language statements. Eventhough the current debuggers, are already implemented to be a powerful tool, they still cannot do a job of parallel debugger. In this thesis, a computer simulation system has been established by Petri Nets execution providing a convenient and friendly interface as it allows the user to do parallel program debugging. The Parallel Debugger is simulated by providing a time parameter for each transition and thus simulating the net performance. Hitherto, this time parameter can either be constant or exponentially distributed

Performance monitoring of parallel applications at large grain level

This thesis is an attempt to create a methodology to analyze the performance of parallel applications on a wide variety of platforms and programming environments. First we determined the monitoring functions required to collect traces for accurate representation of the parallel application. We used the Extended Large Grain Data Flow (E L G D F) representation of an application to determine granularity and which monitoring functions should be inserted for sufficient feedback to application designer. The monitoring routines ( real time clock access procedures ) with a common interface were developed for the Sequent [superscript] TM multiprocessor machine and the C-Linda programming environment . We also developed an Execution Profile Analyzer( E PA ) for post-processing the traces. The E P A gives feedback to the mapping and scheduling ( TaskGrapher ) tool by providing actual performance data. These tools are being developed as a part of Parallel Programming Support Environment ( P P S E) research . Results indicate that when actual grain execution time is made available to scheduling tools, accurate projections of program behavior are obtained

QuickStep, a system for performance monitoring and debugging parallel applications on the Alewife multiprocessor

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 77-78).by Sramana Mitra.M.S

Detecting and correcting errors in parallel object oriented systems

Our research concerns the development of an operational formalism for the in-source specification of parallel, object oriented systems. These specifications are used to enunciate the behavioural semantics of objects, as a means of enhancing their reliability. A review of object oriented languages concludes that the advance in language sophistication heralded by the object oriented paradigm has, so far, failed to produce a commensurate increase in software reliability. The lack of support in modern object oriented languages for the notion of 'valid object behaviour', as distinct from state and operations, undermines the potential power of the abstraction. Furthermore, it weakens the ability of such languages to detect behavioural problems, manifest at run-time. As a result, in-language facilities for the signalling and handling of undesirable program behaviours or states (for example, assertions) are still in their infancy. This is especially true of parallel systems, where the scope for subtle error is greater. The first goal of this work was to construct an operational model of a general purpose, parallel, object oriented system in order to ascertain the fundamental set of event classes that constitute its observable behaviour. Our model is built on the CSP process calculus and uses a subset of the Z notation to express some aspects of state. This alphabet was then used to construct a formalism designed to augment each object type description with the operational specification of an object's behaviour: Event Pattern Specifications (EPS). EPSs are a labeled list of acceptable object behaviours which form part of the definition of every type. The thesis includes a description of the design and implementation of EPSs as part of an exception handling mechanism for the parallel, object oriented language Solve. Using this implementation, we have established that the run-time checking of EPS specifications is feasible, albeit it with considerable overhead. Issues arising from this implementation are discussed and we describe the visualization of EPSs and their use in semantic browsing