Compiler-directed array interleaving for reducing energy in multi-bank memories

With the increased use of embedded/portable devices such as smart cellular phones, pagers, PDAs, hand-held comput-ers, and CD players, improving energy efficiency is becoming a critical issue. To develop a truly energy-efficient system, en-ergy constraints should be taken into account early in the de-sign process; i.e., at the source level in software compilation and behavioral level in hardware compilation. Source-level optimizations are particularly important in data-dominated media applications that have become pervasive in energy-constrained mobile environments. This paper focuses on improving the effectiveness of en-ergy savings from using multiple low-power operating modes provided in current memory modules. We propose a source-level data space transformation technique called array inter-leaving that colocates simultaneously used array elements in a small set of memory modules. We validate the effectiveness of this transformation using a set of array-dominated bench-marks and observe significant savings in memory energy.