Globally Precise-restartable Execution of Parallel Programs

Emerging trends in computer design and use are likely to make exceptions, once rare, the norm, especially as the system size grows. Due to exceptions, arising from hardware faults, approximate computing, dynamic resource management, etc., successful and error-free execution of programs may no longer be assured. Yet, designers will want to tolerate the exceptions so that the programs execute completely, efficiently and without external intervention. Modern computers easily handle exceptions in sequential programs, using precise interrupts. But they are ill-equipped to handle exceptions in parallel programs, which are growing in prevalence. In this work we introduce the notion of globally precise-restartable execution of parallel programs, analogous to precise-interruptible execution of sequential programs. We present a software runtime recovery system based on the approach to handle exceptions in suitably-written parallel programs. Qualitative and quantitative analyses show that the proposed system scales with the system size, especially when exceptions are frequent, unlike the conventional checkpoint-and-recovery method.