Search

The movement toward 3D fabrication coupled with Network-on-Chip (NoC) aims to improve area, performance, power, and scalability of many-core systems. However, reliability issue as a perpetual challenge in advanced silicon technology imperils it. Aging is an emerging reliability concern, which degrades the system's performance and causes timing failure eventually. Bias-Temperature-Instability (BTI) and Hot-Carrier-Injection (HCI) are the dominant aging mechanisms, which escalate in high temperature and stress (i.e., usage). In addition to the intra-layer temperature variations, 3D NoCs experience inter-layer temperature variations, which demand necessary investigations for aging as compared to 2D NoC. In this paper, we propose AROMa, an aging-aware deadlock-free adaptive routing algorithm integrated with a novel online aging monitoring system for 3D NoCs. The monitoring system in AROMa exploits Distributed-Centralized-Aging-Table (D-CAT) to obtain routers’ aging rates for each layer of 3D NoCs periodically. Consequently, AROMa swaps between different k-best source-destination shortest paths periodically to avoid highly aged routers, force them in recovery phase of BTI, and accordingly balance aging in the network. We prove that AROMa is deadlock free. Our extensive experimental analysis using gem5 full system mode for PARSEC and SPLASH-2 benchmark suites concludes that AROMa outperforms state-of-the-art works while improving age imbalance by 70 percent and maximum age by 35 percent in 3D NoC with negligible overheads. [ABSTRACT FROM AUTHOR]

Recently, Through-Silicon-Via (TSV) has been more popular to provide faster inter-layer communication in three-dimensional Networks-on-Chip (3D NoCs). However, the area overhead of TSVs reduces wafer utilization and yield which impact design of 3D architectures using a large number of TSVs such as homogeneous 3D NoCs topologies. Also, 3D routers require more memory and thus they are more power hungry than conventional 2D routers. Alternatively, hybrid 3D NoCs combine both the area and performance benefits of 2D and 3D router architectures by using a limited number of TSVs. Existing hybrid architectures suffer from higher packet delays as they do not consider the dynamic communication patterns of different application and their NoC resource usage. We propose a novel algorithm to systematically generate hybrid 3D NoC topologies for a given application such that the vertical connections are minimized while the NoC performance is not sacrificed. The proposed algorithm analyses the target application and generates hybrid architectures by efficiently redistributing the vertical links and buffer spaces based on their utilizations. Furthermore, the algorithm has been evaluated with synthetic and various real-world traffic patterns. Experimental results show that the proposed algorithm generates optimized architectures with lower energy consumption and a significant reduction in packet delay compared to the existing solutions. [ABSTRACT FROM PUBLISHER]

3D integration opens up new opportunities for future multiprocessor chips by enabling fast and highly scalable 3D Network-on-Chip (NoC) topologies. However, in an aim to reduce the cost of Through-silicon via (TSV), partially vertically connected NoCs, in which only a few vertical TSV links are available, have been gaining relevance. To reliably route packets under such conditions, we introduce a lightweight, efficient and highly resilient adaptive routing algorithm targeting partially vertically connected 3D-NoCs named First-Last. It requires a very low number of virtual channels (VCs) to achieve deadlock-freedom (2 VCs in the East and North directions and 1 VC in all other directions), and guarantees packet delivery as long as one healthy TSV connecting all layers is available anywhere in the network. An improved version of our algorithm, named Enhanced-First-Last is also introduced and shown to dramatically improve performance under low TSV availability while still using less virtual channels than state-of-the-art algorithms. A comprehensive evaluation of the cost and performance of our algorithms is performed to demonstrate their merits with respects to existing solutions. [ABSTRACT FROM AUTHOR]

3D ICs can take advantage of a scalable communication platform, commonly referred to as the Networks-on-Chip (NoC). In the basic form of 3D-NoC, all routers are vertically connected. Partially connected 3D-NoC has emerged because of physical limitations of using vertical links. Routing is of great importance in such partially connected architectures. A high-performance, fault-tolerant and adaptive routing strategy with respect to the communication flow among the cores is crucial while freedom from livelock and deadlock has to be guaranteed. In this paper we introduce a new routing algorithm for partially connected 3D-NoCs. The routing algorithm is adaptive and tolerates the faults on vertical links as compared to the predesigned routing algorithms. Our results show a $40-50\%$ improvement in the fraction of intact inter-level communications when the fault tolerant algorithm is used. This routing algorithm is light-weight and has only one virtual channel along the $Y$ dimension. [ABSTRACT FROM AUTHOR]