Selective Code Duplication for Soft Error Protection on VLIW Architectures

Very Long Instruction Word, or VLIW, architectures have received much attention in specific-purpose applications such as scientific computation, digital signal processing, and even safety-critical systems. Several compilation techniques for VLIW architectures have been proposed in order to improve the performance, but there is a lack of research to improve reliability against soft errors. Instruction duplication techniques have been proposed by exploiting unused instruction slots (i.e., NOPs) in VLIW architectures. All the instructions cannot be replicated without additional code lines. Additional code lines are required to increase the number of duplicated instructions in VLIW architectures. Our experimental results show that 52% performance overhead as compared to unprotected source code when we duplicate all the instructions. This considerable performance overhead can be inapplicable for resource-constrained embedded systems so that we can limit the number of additional NOP instructions for selective protection. However, the previous static scheme duplicates instructions just in sequential order. In this work, we propose packing-oriented duplication to maximize the number of duplicated instructions within the same peroformance overhead bounds. Our packing-oriented approach can duplicate up to 18% more instructions within the same performance overheads compared to the previous static duplication techniques.

Selective Protection in Turkey

By analyzing the case of Turkey as a refugee-receiving country, chapter 5 allows a comparison with the more typical Egyptian case laid out in chapter 4. One of only a handful of countries that retains a geographical limitation to the 1951 Refugee Convention, Turkey has experienced several mass refugee influxes and boasts one of the largest refugee resettlement programs. The conventional wisdom in this “extreme” case emphasizes a dichotomy between European and non-European refugees. This chapter establishes that Turkish policies are more nuanced than this conventional wisdom expects. Once again, it draws on a range of sources to examine how Turkey responded to Bulgarians, Iraqis, Iranians, refugees from the former Yugoslavia, and refugees from Soviet and post-Soviet states. This analysis reveals that even seemingly general policies that exist on the books were applied selectively, a pattern that betrays the influence of foreign policy and ethnic politics on Turkey’s asylum policies.