A numerical optimization-based methodology for application robustification: Transforming applications for error tolerance

There have been several attempts at correcting process variation induced errors by identifying and masking these errors at the circuit and architecture level. These approaches take up valuable die area and power on the chip. As an alternative, we explore the feasibility of an approach that allows these errors to occur freely, and handle them in software, at the algorithmic level. In this paper, we present a general approach to converting applications into an error tolerant form by recasting these applications as numerical optimization problems, which can then be solved reliably via stochastic optimization. We evaluate the potential robustness and energy benefits of the proposed approach using an FPGA-based framework that emulates timing errors in the floating point unit (FPU) of a Leon3 processor. We show that stochastic versions of applications have the potential to produce good quality outputs in the face of timing errors under certain assumptions. We also show that good quality results are possible for both intrinsically robust algorithms as well as fragile applications under these assumptions.