DaemonGuard: O/S-assisted selective software-based Self-Testing for multi-core systems

As technology scales deep into the sub-micron regime, transistors become less reliable. Future systems are widely predicted to suffer from considerable aging and wear-out effects. This ominous threat has urged system designers to develop effective run-time testing methodologies that can monitor and assess the system´s health. In this work, we investigate the potential of online software-based functional testing at the granularity of individual microprocessor core components in multi-core systems. While existing techniques monolithically test the entire core, our approach aims to reduce testing time by avoiding the over-testing of under-utilized units. To facilitate fine-grained testing, we introduce DaemonGuard, a framework that enables the real-time observation of individual sub-core modules and performs on-demand selective testing of only the modules that have recently been stressed. The monitoring and test-initiation process is orchestrated by a transparent, minimally-intrusive, and lightweight operating system process that observes the utilization of individual datapath components at run-time. We perform a series of experiments using a full-system, execution-driven simulation framework running a commodity operating system, real multi-threaded workloads, and test programs. Our results indicate that operating-system-assisted selective testing at the sub-core level leads to substantial savings in testing time and very low impact on system performance.