Analysis of an energy efficient optimistic TMR scheme

For mission critical real-time applications, such as satellite and surveillance systems, a high level of reliability is desired as well as low energy consumption. In this paper, we propose a general system power model and explore the optimal speed setting to minimize system energy consumption for an optimistic TMR (OTMR) scheme. The performance of OTMR is compared with that of TMR (triple modular redundancy) and duplex with respect to energy and reliability. The results show that OTMR is always better than TMR by achieving higher levels of reliability and consuming less energy. With checkpoint overhead and recovery, duplex is not applicable when system load is high. However, duplex may be more energy efficient than OTMR depending on system static power and checkpointing overhead. Moreover, with one recovery section, duplex achieves comparable levels of reliability as that of OTMR.