Fault Tolerance for RRAM-Based Matrix Operations

An RRAM-based computing system (RCS) provides an energy efficient hardware implementation of vector-matrix multiplication for machine-learning hardware. However, it is vulnerable to faults due to the immature RRAM fabrication process. We propose an efficient fault tolerance method for RCS; the proposed method, referred to as extended-ABFT (X-ABFT), is inspired by algorithm-based fault tolerance (ABFT). We utilize row checksums and test-input vectors to extract signatures for fault detection and error correction. We present a solution to alleviate the overflow problem caused by the limited number of voltage levels for the test-input signals. Simulation results show that for a Hopfield classifier with faults in 5% of its RRAM cells, X-ABFT allows us to achieve nearly the same classification accuracy as in the fault-free case.