Spatial Memoization: Concurrent Instruction Reuse to Correct Timing Errors in SIMD Architectures

This brief proposes a novel technique to alleviate the cost of timing error recovery, building upon the lockstep execution of single-instruction-multiple- data (SIMD) architectures. To support spatial memoization at the instruction level, we propose a single-strong-lane-multiple-weak-lane (SSMW) architecture. Spatial memoization exploits the value locality inside parallel programs, memoizes the result of an error-free execution of an instruction on the SS lane, and concurrently reuses the result to spatially correct errant instructions across MW lanes. Experiment results on Taiwan Semiconductor Manufacturing Company 45-nm technology confirm that this technique avoids the recovery for 62% of the errant instructions on average, for both error-tolerant and error-intolerant general-purpose applications.