ProactiveDRAM: A DRAM-initiated retention management scheme

DRAM cells are leaky and need periodic refresh, which hurts system performance and consumes additional energy. With DRAM scaling towards sub-20nm process technology, we expect a significant portion of DRAM cells become weak cells and require a higher refresh rate, resulting in even higher refresh overhead. A possible solution is to selectively refresh those weak cells using a higher frequency but still refresh the majority at the nominal rate. However, how to provide a multi-rate DRAM refresh scheme is not straightforward. Previous work on this topic was built on an obsolete refresh framework and was incompatible to modern DRAM standards, making it challenging to be adopted in practice. In this work, we propose ProactiveDRAM, a novel scheme that allows DRAM proactively guides the timing of weak cell refresh management and reuses memory controllers´ capability in command scheduling. ProactiveDRAM offers a smart retention-aware refresh on the DRAM row granularity, and more importantly, it can be built atop any modern DRAM architecture. Our simulation results show that ProactiveDRAM can handle 1% (or even 10%) weak row population with negligible performance and energy overhead1.