OTERA-III: Online Test Strategies for Reliable Reconfigurable Architectures - From Reliability to Guaranteed System Performability: A Multi-Layer Approach

OTERA项目自2011年以来一直得到资助，目前正在申请第三阶段的资助。在卓有成效的合作中，两个小组(CES和ITI)结合了他们在运行时系统和可重构体系结构(CES)以及高效在线测试、诊断和容错(ITI)方面的专业知识。这导致在著名的同行评议会议和交易上发表了8篇论文。资金阶段I和II针对可重构结构中的永久性结构故障(固定和转换延迟故障模型)和暂时性故障(配置位中的软错误，位翻转/RAP故障模型)。在资金阶段III，目标体系结构是多任务系统，多个任务之间共享异类运行时可重构资源。该可重构结构是细粒度的，并在基于SRAM的现场可编程门阵列上实现。我们的目标是通过延长系统寿命和可用性(即通过修复、优雅降级或受控应力分布)来提高可靠性，提高系统和任务的可靠性，并保证系统的可执行性。我们的项目跨越五层(从高到低)：系统、任务、加速功能、加速器(放置在容器中)和逻辑。在每一层，可信性动作可以影响到其他层，这跨越了巨大的搜索空间，以实现任务的可信性要求。因此，OTERA项目为探索不同的多层可靠性策略提供了一个平台。多层可靠性优化旨在(I)在系统任务时间内保证指定水平的系统可执行性(即在期望的性能水平下可靠地运行系统)；(Ii)满足在运行时变化的环境、功能和非功能条件下并发执行任务的可靠性；(Iii)提供系统在多维参数空间(可控参数，例如冗余度、电压水平等)中的自适应。

The OTERA Project has been funded since 2011 and is now applying for the third funding phase. In a fruitful cooperation, the two groups (CES and ITI) combined their expertise in runtime systems and reconfigurable architectures (CES), as well as efficient online test, diagnosis and fault-tolerance (ITI). This lead to 8 papers published at renowned peer-reviewed conferences and transactions. Funding Phase I and II have targeted permanent structural faults (stuck-at and transition delay fault models) and transient faults (soft errors in configuration bits, bit-flip/RAP fault model) in the reconfigurable fabric.In Funding Phase III the target architecture is a multi-tasking system with heterogeneous runtime reconfigurable resources shared among multiple tasks. The reconfigurable fabric is fine-grained and implemented on SRAM-based FPGAs. We target to improve dependability by increasing system lifetime and availability (i.e. via repair, graceful degradation, or controlled stress distribution), raising system and task reliability, and guaranteeing system performability.The architecture of this project allows to dynamically adapt the system at multiple layers. Our project spans five layers (from highest to lowest): System, Task, Accelerated Functions, Accelerators (placed into containers), and Logic. At each layer, dependability actions can be applied with impact on other layers, which spans a vast search space to achieve the dependability requirements of tasks. Thus, the OTERA project offers a platform for exploration of different multi-layer dependability strategies.The multi-layer dependability optimization aims to (i) guarantee a specified level of system performability over the system mission time (i.e. reliable system operation at a desired level of performance), (ii) satisfy the dependability of concurrently executing tasks under runtime-changing environment, functional and non-functional conditions, (iii) provide self-adaption of the system in a multi-dimensional parameter space (controllable parameters, e.g. degree of redundancy, voltage level etc.).