Smart cache cleaning: Energy efficient vulnerability reduction in embedded processors

Incessant and rapid technology scaling has brought us to a point where todays, and future transistors are susceptible to transient errors induced by energy carrying particles, called soft errors. Within a processor, the sheer size and nature of data in the caches render it most vulnerable to electrical interferences on static data in the cache. Data in the cache is vulnerable to corruption by soft errors, for the time it remains in the cache. Write-through and early-write-back [17] cache configurations reduce the time for vulnerable data in the cache, at the cost of increased memory writes and therefore energy. We propose a smart cache cleaning methodology, that enables copying of only specific vulnerable cache blocks into the memory at chosen times, thereby ensuring data cache protection with minimal memory writes. Our experiments over LINPACK and Livermore benchmarks demonstrate 26% reduced energy-vulnerability product compared to that of hardware cache configurations.