Energy Optimization of a Multi-bank Main Memory

A growing part of the energy, battery-driven embedded system, is consumed by the off-chip main memory. In order to minimize this memory consumption, an architectural solution is recently adopted. It consists of multi-banking the addressing space instead of monolithic memory. The main advantage in this approach is the capability of setting banks in low power modes when they are not accessed, such that only the accessed bank is maintained in active mode. In this paper we investigate how this power management capability built into modern DRAM devices can be handled for multi-task applications. We aim to find, at system level design, both an efficient allocation of applications tasks to memory banks, and the memory configuration that lessen the energy consumption: number of banks and the size of each bank. Results show the effectiveness of this approach and the large energy savings.