Simulated Console Lights for Parallel Programs

Debugging parallel programs would be hard enough if you could only know what your tasks were doing. Did one task finish early? Did another task stop because of a divide exception? How many of the tasks understood the last debug command? Are any tasks waiting for a message that never arrived? Exactly where in the calculation is each task? Unfortunately, it is hard to get answers to these questions from most parallel debuggers. We have added four sets of simulated console lights to IVD, a prototype parallel debugger, in an attempt to address this problem.