Making DRAM stronger against row hammering

Modern DRAM suffers from a new problem called row hammering. The problem is expected to become more severe in future DRAMs mostly due to increased inter-row coupling at advanced technology. In order to address this problem, we present a probabilistically managed table (called PRoHIT) implemented on the DRAM chip. The table keeps track of victim row candidates in a probabilistic way and, in case of auto-refresh, the topmost entry is additionally refreshed thereby mitigating the row hammering problem. Our experiments with PARSEC benchmark and synthetic traces show that PRoHIT outperforms the state-of-the-art method, PARA, by 35.7% (PARSEC) in terms of the reduction ratio of row-hammer cases. Our proposed method also shows constantly superior performance to PARA for synthetic traces.