Sorting in Memristive Memory

Sorting is needed in many application domains. The data is read from memory and sent to a general purpose processor or application specific hardware for sorting. The sorted data is then written back to the memory. Reading/writing data from/to memory and transferring data between memory and processing unit incur a large latency and energy overhead. In this work, we develop, to the best of our knowledge, the first architectures for in-memory sorting of data. We propose two architectures. The first architecture is applicable to the conventional format of representing data, weighted binary radix. The second architecture is proposed for the developing unary processing systems where data is encoded as uniform unary bitstreams. The two architectures have different advantages and disadvantages, making one or the other more suitable for a specific application. However, the common property of both is a significant reduction in the processing time compared to prior sorting designs. Our evaluations show on average 37x and 138x energy reduction for binary and unary designs, respectively, as compared to conventional CMOS off-memory sorting systems.