WISEDRAM: A Reliable Bitwise In-DRAM Accelerator

Processing-in-Memory (PIM) aims to address the costly data movement between processing elements and memory subsystem, by computing simple operations inside DRAM in parallel. The large capacity, wide activation size during cell access, and the maturity of DRAM technology, make this technology a great choice for PIM techniques. Nonetheless, vulnerability to process variation and noises, internal leakage of the cells, and high latency in cell access, limit the utilization of processing in DRAMs for real-world applications. This work proposes a fast PIM technique, called WISEDRAM, which leverages one row of special cells, called X-cells, to enable in-DRAM bulk-bitwise operations. Unlike previous approaches, WISEDRAM retains the conventional DRAM cell access procedure, thereby ensuring the reliability of cell access for reads and writes at a level equivalent to that of conventional DRAMs. Compared with the state-of-the-art, WISEDRAM exhibits $22 \%$ reduction in average bitwise computation latency and a $71 \%$ improvement in XOR operation execution speed, while imposing an area overhead of $1.6 \%$.