Process Variation Aware Cache Leakage Management

In a few technology generations, limitations of fabrication processes have made accurate design time power estimates a daunting challenge. Static leakage current which comprises a significant fraction of total power due to large on-chip caches, is exponentially dependent on widely varying physical parameters such as gate length, gate oxide thickness, and dopant ion concentration. In large structures like on-chip caches, this may mean that one portion of a cache may consume an order of magnitude larger static power than equivalently sized regions. Under this climate, egalitarian management of physical resources is clearly untenable. In this paper, we analyze the effects of within-die and die-to-die leakage variation for on-chip caches. We then propose way prioritization, a manufacturing variation aware scheme that minimizes cache leakage energy. Our results show that significant average power reductions are possible without undue hardware complexity or performance compromise