An energy-conscious algorithm for memory port allocation

Multiport memories are extensively used in modern system designs because of the performance advantages they offer. The increased memory access throughput could lead to significantly faster schedules in behavioral synthesis. However, they also have an associated area and energy penalty. We describe a technique for mapping data accesses to multiport memories during behavioral synthesis that results in significantly better energy characteristics than an unoptimized multiport design. The technique consists of an initial colouring of the array access nodes in the data flow graph based on spatial locality, followed by attempts to consecutively access memory locations with the same colour on the same port. Our experiments on several applications indicate a significant reduction in address bus switching activity, leading to an overall energy reduction over an unoptimized design, while still maintaining a performance advantage over a single-port solution.