Using run-time reverse-engineering to optimize DRAM refresh
Deepak M. Mathew, Éder F. Zulian, Matthias Jung, Kira Kraft, Christian Weis, Bruce Jacob, Norbert Wehn · Proceedings of the International Symposium on Memory Systems · 2017
The overhead of DRAM refresh is increasing with each density generation. To help offset some of this overhead, JEDEC designed the modern Auto-Refresh command with a highly optimized architecture internal to the DRAM---an architecture that violates the timing rules external controllers must observe and obey during normal operation. Numerous refresh-reduction schemes manually refresh the DRAM row-by-row, eliminating unnecessary refreshes to improve both energy and performance of the DRAM. However, it has been shown that modern Auto-Refresh is incompatible with these schemes, that their manual refreshing of specified rows through explicit Activate and Precharge precludes them from exploiting the architectural optimizations available internally for Auto-Refresh operations.