Quantitative analysis of control flow checking mechanisms for soft errors

Control Flow Checking (CFC) based techniques have gained a reputation of providing effective, yet low-overhead protection from soft errors. The basic idea is that if the control ow { or the sequence of instructions that are executed { is correct, then most probably the execution of the program is correct. Al- though researchers claim the effectiveness of the proposed CFC techniques, we argue that their evaluation has been inadequate and can even be wrong! Recently, the metric of vulnerabil- ity has been proposed to quantify the susceptibility of compu- tation to soft errors. Laced with this comprehensive metric, we quantitatively evaluate the effectiveness of several existing CFC schemes, and obtain surprising results. Our results show that existing CFC techniques are not only ineffective in pro- tecting computation from soft errors, but that they incur addi- tional power and performance overheads. Software-only CFC protection schemes (CFCSS [14], CFCSS+NA [2], and CEDA [18]) increase system vulnerability by 18% to 21% with 17% to 38% performance overhead; Hybrid CFC protection technique, CFEDC [4] also increases the vulnerability by 5%; While the vulnerability remains almost the same for hardware only CFC protection technique, CFCET [15], they cause overheads of de- sign cost, area, and power due to the hardware modications required for their implementations.