The survivability of design-specific spare placement in FPGA architectures with high defect rates

Abstract

We address the problem of optimizing fault tolerance in FPGA architectures with high defect rates (such as nano-FPGAs) without significantly degrading performance. Our methods address fault tolerance during the placement and reconfiguration stages of FPGA programming. First, we provide several complexity results for both the fault reconfiguration and fault-tolerance placement problems. Then, we propose a placement algorithm which, in the presence of randomly generated faults, optimizes spare placement to maximize the probability that the FPGA can be reconfigured to meet a specified timing constraint. We also give heuristics for reconfiguration after faults have been detected. Despite the hardness results for both the placement and reconfiguration problems, we show our heuristics perform well in simulation (in one scenario, increasing the probability of successful reconfiguration by as much as 55% compared to a uniform spare placement).