Energy efficient page initialization for storage class memory

Emerging non-volatile memory technologies are promising to serve as storage class memory to replace hard disk and even DRAM. In this paper, we focus on the energy issue of Storage Class Memory (SCM) when one exploits its scalability and near-DRAM latency to provide large-capacity memory system. SCM, such as PCM and RRAM, incurs high write energy and write energy asymmetry. Especially, the energy of writing bit “0” is different from that of writing bit “1”. Page initialization is a common operation in most operating systems. This paper observes a large fraction of energy consumption in current memory system due to page initialization, which even increases in SCM-based memory system. We propose EPFI, an energy-aware page frame initialization technique to reduce the energy cost of SCM. EPFI adaptively sets the initial value of all bits in a page frame to a state that consumes lower energy. The evaluation results show that our technique reduces initialization energy and total energy by 26.5 % and 6.3 % on average, compared to the conventional OS page initialization.