Global Congestion and Fault Aware Wireless Interconnection Framework for Multicore Systems

Multicore processors are getting more common in the implementation of all type of computing demands, starting from personal computers to the large server farms for high computational demanding applications. The network-on-chip provides a better alternative to the traditional bus based communication infrastructure for this multicore system. Conventional wire-based NoC interconnect faces constraints due to their long multi-hop latency and high power consumption. Furthermore high traffic generating applications sometimes creates congestion in such system further degrading the systems performance. In this thesis work, a novel two-state congestion aware wireless interconnection framework for network chip is presented. This WiNoC system was designed to able to dynamically redirect traffic to avoid congestion based on network condition information shared among all the core tiles in the system. Hence a novel routing scheme and a two-state MAC protocol is proposed based on a proposed two layer hybrid mesh-based NoC architecture. The underlying mesh network is connected via wired-based interconnect and on top of that a shared wireless interconnect framework is added for single-hop communication. The routing scheme is non-deterministic in nature and utilizes the principles from existing dynamic routing algorithms. The MAC protocol for the wireless interface works in two modes. The first is data mode where a token-based protocol is utilized to transfer core data. And the second mode is the control mode where a broadcast-based communication protocol is used to share the network congestion information. The work details the switching methodology between these two modes and also explain, how the routing scheme utilizes the congestion information (gathered during the control mode) to route data packets during normal operation mode. The proposed work was modeled in a cycle accurate network simulator and its performance were evaluated against traditional NoC and WiNoC designs

Network-on-Chip

Limitations of bus-based interconnections related to scalability, latency, bandwidth, and power consumption for supporting the related huge number of on-chip resources result in a communication bottleneck. These challenges can be efficiently addressed with the implementation of a network-on-chip (NoC) system. This book gives a detailed analysis of various on-chip communication architectures and covers different areas of NoCs such as potentials, architecture, technical challenges, optimization, design explorations, and research directions. In addition, it discusses current and future trends that could make an impactful and meaningful contribution to the research and design of on-chip communications and NoC systems

Reliability-aware and energy-efficient system level design for networks-on-chip

2015 Spring.Includes bibliographical references.With CMOS technology aggressively scaling into the ultra-deep sub-micron (UDSM) regime and application complexity growing rapidly in recent years, processors today are being driven to integrate multiple cores on a chip. Such chip multiprocessor (CMP) architectures offer unprecedented levels of computing performance for highly parallel emerging applications in the era of digital convergence. However, a major challenge facing the designers of these emerging multicore architectures is the increased likelihood of failure due to the rise in transient, permanent, and intermittent faults caused by a variety of factors that are becoming more and more prevalent with technology scaling. On-chip interconnect architectures are particularly susceptible to faults that can corrupt transmitted data or prevent it from reaching its destination. Reliability concerns in UDSM nodes have in part contributed to the shift from traditional bus-based communication fabrics to network-on-chip (NoC) architectures that provide better scalability, performance, and utilization than buses. In this thesis, to overcome potential faults in NoCs, my research began by exploring fault-tolerant routing algorithms. Under the constraint of deadlock freedom, we make use of the inherent redundancy in NoCs due to multiple paths between packet sources and sinks and propose different fault-tolerant routing schemes to achieve much better fault tolerance capabilities than possible with traditional routing schemes. The proposed schemes also use replication opportunistically to optimize the balance between energy overhead and arrival rate. As 3D integrated circuit (3D-IC) technology with wafer-to-wafer bonding has been recently proposed as a promising candidate for future CMPs, we also propose a fault-tolerant routing scheme for 3D NoCs which outperforms the existing popular routing schemes in terms of energy consumption, performance and reliability. To quantify reliability and provide different levels of intelligent protection, for the first time, we propose the network vulnerability factor (NVF) metric to characterize the vulnerability of NoC components to faults. NVF determines the probabilities that faults in NoC components manifest as errors in the final program output of the CMP system. With NVF aware partial protection for NoC components, almost 50% energy cost can be saved compared to the traditional approach of comprehensively protecting all NoC components. Lastly, we focus on the problem of fault-tolerant NoC design, that involves many NP-hard sub-problems such as core mapping, fault-tolerant routing, and fault-tolerant router configuration. We propose a novel design-time (RESYN) and a hybrid design and runtime (HEFT) synthesis framework to trade-off energy consumption and reliability in the NoC fabric at the system level for CMPs. Together, our research in fault-tolerant NoC routing, reliability modeling, and reliability aware NoC synthesis substantially enhances NoC reliability and energy-efficiency beyond what is possible with traditional approaches and state-of-the-art strategies from prior work

Network-on-Chip

Addresses the Challenges Associated with System-on-Chip Integration Network-on-Chip: The Next Generation of System-on-Chip Integration examines the current issues restricting chip-on-chip communication efficiency, and explores Network-on-chip (NoC), a promising alternative that equips designers with the capability to produce a scalable, reusable, and high-performance communication backbone by allowing for the integration of a large number of cores on a single system-on-chip (SoC). This book provides a basic overview of topics associated with NoC-based design: communication infrastructure design, communication methodology, evaluation framework, and mapping of applications onto NoC. It details the design and evaluation of different proposed NoC structures, low-power techniques, signal integrity and reliability issues, application mapping, testing, and future trends. Utilizing examples of chips that have been implemented in industry and academia, this text presents the full architectural design of components verified through implementation in industrial CAD tools. It describes NoC research and developments, incorporates theoretical proofs strengthening the analysis procedures, and includes algorithms used in NoC design and synthesis. In addition, it considers other upcoming NoC issues, such as low-power NoC design, signal integrity issues, NoC testing, reconfiguration, synthesis, and 3-D NoC design. This text comprises 12 chapters and covers: The evolution of NoC from SoC—its research and developmental challenges NoC protocols, elaborating flow control, available network topologies, routing mechanisms, fault tolerance, quality-of-service support, and the design of network interfaces The router design strategies followed in NoCs The evaluation mechanism of NoC architectures The application mapping strategies followed in NoCs Low-power design techniques specifically followed in NoCs The signal integrity and reliability issues of NoC The details of NoC testing strategies reported so far The problem of synthesizing application-specific NoCs Reconfigurable NoC design issues Direction of future research and development in the field of NoC Network-on-Chip: The Next Generation of System-on-Chip Integration covers the basic topics, technology, and future trends relevant to NoC-based design, and can be used by engineers, students, and researchers and other industry professionals interested in computer architecture, embedded systems, and parallel/distributed systems

A Survey of Software-Defined Networks-on-Chip: Motivations, Challenges and Opportunities

Current computing platforms encourage the integration of thousands of processing cores, and their interconnections, into a single chip. Mobile smartphones, IoT, embedded devices, desktops, and data centers use Many-Core Systems-on-Chip (SoCs) to exploit their compute power and parallelism to meet the dynamic workload requirements. Networks-on-Chip (NoCs) lead to scalable connectivity for diverse applications with distinct traffic patterns and data dependencies. However, when the system executes various applications in traditional NoCs—optimized and fixed at synthesis time—the interconnection nonconformity with the different applications’ requirements generates limitations in the performance. In the literature, NoC designs embraced the Software-Defined Networking (SDN) strategy to evolve into an adaptable interconnection solution for future chips. However, the works surveyed implement a partial Software-Defined Network-on-Chip (SDNoC) approach, leaving aside the SDN layered architecture that brings interoperability in conventional networking. This paper explores the SDNoC literature and classifies it regarding the desired SDN features that each work presents. Then, we described the challenges and opportunities detected from the literature survey. Moreover, we explain the motivation for an SDNoC approach, and we expose both SDN and SDNoC concepts and architectures. We observe that works in the literature employed an uncomplete layered SDNoC approach. This fact creates various fertile areas in the SDNoC architecture where researchers may contribute to Many-Core SoCs designs.Las plataformas informáticas actuales fomentan la integración de miles de núcleos de procesamiento y sus interconexiones, en un solo chip. Los smartphones móviles, el IoT, los dispositivos embebidos, los ordenadores de sobremesa y los centros de datos utilizan sistemas en chip (SoC) de muchos núcleos para explotar su potencia de cálculo y paralelismo para satisfacer los requisitos de las cargas de trabajo dinámicas. Las redes en chip (NoC) conducen a una conectividad escalable para diversas aplicaciones con distintos patrones de tráfico y dependencias de datos. Sin embargo, cuando el sistema ejecuta varias aplicaciones en las NoC tradicionales -optimizadas y fijadas en el momento de síntesis, la disconformidad de la interconexión con los requisitos de las distintas aplicaciones genera limitaciones en el rendimiento. En la literatura, los diseños de NoC adoptaron la estrategia de redes definidas por software (SDN) para evolucionar hacia una solución de interconexión adaptable para los futuros chips. Sin embargo, los trabajos estudiados implementan un enfoque parcial de red definida por software en el chip (SDNoC) de SDN, dejando de lado la arquitectura en capas de SDN que aporta interoperabilidad en la red convencional. Este artículo explora la literatura sobre SDNoC y la clasifica en función de las características SDN que presenta cada trabajo. A continuación, describimos los retos y oportunidades detectados a partir del estudio de la literatura. Además, explicamos la motivación para un enfoque SDNoC, y exponemos los conceptos y arquitecturas de SDN y SDNoC. Observamos que los trabajos en la literatura emplean un enfoque SDNoC por capas no completo. Este hecho crea varias áreas fértiles en la arquitectura SDNoC en las que los investigadores pueden contribuir a los diseños de SoCs de muchos núcleos

Architecting a One-to-many Traffic-Aware and Secure Millimeter-Wave Wireless Network-in-Package Interconnect for Multichip Systems

With the aggressive scaling of device geometries, the yield of complex Multi Core Single Chip(MCSC) systems with many cores will decrease due to the higher probability of manufacturing defects especially, in dies with a large area. Disintegration of large System-on-Chips(SoCs) into smaller chips called chiplets has shown to improve the yield and cost of complex systems. Therefore, platform-based computing modules such as embedded systems and micro-servers have already adopted Multi Core Multi Chip (MCMC) architectures overMCSC architectures. Due to the scaling of memory intensive parallel applications in such systems, data is more likely to be shared among various cores residing in different chips resulting in a significant increase in chip-to-chip traffic, especially one-to-many traffic. This one-to-many traffic is originated mainly to maintain cache-coherence between many cores residing in multiple chips. Besides, one-to-many traffics are also exploited by many parallel programming models, system-level synchronization mechanisms, and control signals. How-ever, state-of-the-art Network-on-Chip (NoC)-based wired interconnection architectures do not provide enough support as they handle such one-to-many traffic as multiple unicast trafficusing a multi-hop MCMC communication fabric. As a result, even a small portion of such one-to-many traffic can significantly reduce system performance as traditional NoC-basedinterconnect cannot mask the high latency and energy consumption caused by chip-to-chipwired I/Os. Moreover, with the increase in memory intensive applications and scaling of MCMC systems, traditional NoC-based wired interconnects fail to provide a scalable inter-connection solution required to support the increased cache-coherence and synchronization generated one-to-many traffic in future MCMC-based High-Performance Computing (HPC) nodes. Therefore, these computation and memory intensive MCMC systems need an energy-efficient, low latency, and scalable one-to-many (broadcast/multicast) traffic-aware interconnection infrastructure to ensure high-performance. Research in recent years has shown that Wireless Network-in-Package (WiNiP) architectures with CMOS compatible Millimeter-Wave (mm-wave) transceivers can provide a scalable, low latency, and energy-efficient interconnect solution for on and off-chip communication. In this dissertation, a one-to-many traffic-aware WiNiP interconnection architecture with a starvation-free hybrid Medium Access Control (MAC), an asymmetric topology, and a novel flow control has been proposed. The different components of the proposed architecture are individually one-to-many traffic-aware and as a system, they collaborate with each other to provide required support for one-to-many traffic communication in a MCMC environment. It has been shown that such interconnection architecture can reduce energy consumption and average packet latency by 46.96% and 47.08% respectively for MCMC systems. Despite providing performance enhancements, wireless channel, being an unguided medium, is vulnerable to various security attacks such as jamming induced Denial-of-Service (DoS), eavesdropping, and spoofing. Further, to minimize the time-to-market and design costs, modern SoCs often use Third Party IPs (3PIPs) from untrusted organizations. An adversary either at the foundry or at the 3PIP design house can introduce a malicious circuitry, to jeopardize an SoC. Such malicious circuitry is known as a Hardware Trojan (HT). An HTplanted in the WiNiP from a vulnerable design or manufacturing process can compromise a Wireless Interface (WI) to enable illegitimate transmission through the infected WI resulting in a potential DoS attack for other WIs in the MCMC system. Moreover, HTs can be used for various other malicious purposes, including battery exhaustion, functionality subversion, and information leakage. This information when leaked to a malicious external attackercan reveals important information regarding the application suites running on the system, thereby compromising the user profile. To address persistent jamming-based DoS attack in WiNiP, in this dissertation, a secure WiNiP interconnection architecture for MCMC systems has been proposed that re-uses the one-to-many traffic-aware MAC and existing Design for Testability (DFT) hardware along with Machine Learning (ML) approach. Furthermore, a novel Simulated Annealing (SA)-based routing obfuscation mechanism was also proposed toprotect against an HT-assisted novel traffic analysis attack. Simulation results show that,the ML classifiers can achieve an accuracy of 99.87% for DoS attack detection while SA-basedrouting obfuscation could reduce application detection accuracy to only 15% for HT-assistedtraffic analysis attack and hence, secure the WiNiP fabric from age-old and emerging attacks

Tree-structured small-world connected wireless network-on-chip with adaptive routing

Traditional Network-on-Chip (NoC) systems comprised of many cores suffer from debilitating bottlenecks of latency and significant power dissipation due to the overhead inherent in multi-hop communication. In addition, these systems remain vulnerable to malicious circuitry incorporated into the design by untrustworthy vendors in a world where complex multi-stage design and manufacturing processes require the collective specialized services of a variety of contractors. This thesis proposes a novel small-world tree-based network-on-chip (SWTNoC) structure designed for high throughput, acceptable energy consumption, and resiliency to attacks and node failures resulting from the insertion of hardware Trojans. This tree-based implementation was devised as a means of reducing average network hop count, providing a large degree of local connectivity, and effective long-range connectivity by means of a novel wireless link approach based on carbon nanotube (CNT) antenna design. Network resiliency is achieved by means of a devised adaptive routing algorithm implemented to work with TRAIN (Tree-based Routing Architecture for Irregular Networks). Comparisons are drawn with benchmark architectures with optimized wireless link placement by means of the simulated annealing (SA) metaheuristic. Experimental results demonstrate a 21% throughput improvement and a 23% reduction in dissipated energy per packet over the closest competing architecture. Similar trends are observed at increasing system sizes. In addition, the SWTNoC maintains this throughput and energy advantage in the presence of a fault introduced into the system. By designing a hierarchical topology and designating a higher level of importance on a subset of the nodes, much higher network throughput can be attained while simultaneously guaranteeing deadlock freedom as well as a high degree of resiliency and fault-tolerance

Robust and Traffic Aware Medium Access Control Mechanisms for Energy-Efficient mm-Wave Wireless Network-on-Chip Architectures

To cater to the performance/watt needs, processors with multiple processing cores on the same chip have become the de-facto design choice. In such multicore systems, Network-on-Chip (NoC) serves as a communication infrastructure for data transfer among the cores on the chip. However, conventional metallic interconnect based NoCs are constrained by their long multi-hop latencies and high power consumption, limiting the performance gain in these systems. Among, different alternatives, due to the CMOS compatibility and energy-efficiency, low-latency wireless interconnect operating in the millimeter wave (mm-wave) band is nearer term solution to this multi-hop communication problem. This has led to the recent exploration of millimeter-wave (mm-wave) wireless technologies in wireless NoC architectures (WiNoC). To realize the mm-wave wireless interconnect in a WiNoC, a wireless interface (WI) equipped with on-chip antenna and transceiver circuit operating at 60GHz frequency range is integrated to the ports of some NoC switches. The WIs are also equipped with a medium access control (MAC) mechanism that ensures a collision free and energy-efficient communication among the WIs located at different parts on the chip. However, due to shrinking feature size and complex integration in CMOS technology, high-density chips like multicore systems are prone to manufacturing defects and dynamic faults during chip operation. Such failures can result in permanently broken wireless links or cause the MAC to malfunction in a WiNoC. Consequently, the energy-efficient communication through the wireless medium will be compromised. Furthermore, the energy efficiency in the wireless channel access is also dependent on the traffic pattern of the applications running on the multicore systems. Due to the bursty and self-similar nature of the NoC traffic patterns, the traffic demand of the WIs can vary both spatially and temporally. Ineffective management of such traffic variation of the WIs, limits the performance and energy benefits of the novel mm-wave interconnect technology. Hence, to utilize the full potential of the novel mm-wave interconnect technology in WiNoCs, design of a simple, fair, robust, and efficient MAC is of paramount importance. The main goal of this dissertation is to propose the design principles for robust and traffic-aware MAC mechanisms to provide high bandwidth, low latency, and energy-efficient data communication in mm-wave WiNoCs. The proposed solution has two parts. In the first part, we propose the cross-layer design methodology of robust WiNoC architecture that can minimize the effect of permanent failure of the wireless links and recover from transient failures caused by single event upsets (SEU). Then, in the second part, we present a traffic-aware MAC mechanism that can adjust the transmission slots of the WIs based on the traffic demand of the WIs. The proposed MAC is also robust against the failure of the wireless access mechanism. Finally, as future research directions, this idea of traffic awareness is extended throughout the whole NoC by enabling adaptiveness in both wired and wireless interconnection fabric

Temperature Evaluation of NoC Architectures and Dynamically Reconfigurable NoC

Advancements in the field of chip fabrication led to the integration of a large number of transistors in a small area, giving rise to the multi–core processor era. Massive multi–core processors facilitate innovation and research in the field of healthcare, defense, entertainment, meteorology and many others. Reduction in chip area and increase in the number of on–chip cores is accompanied by power and temperature issues. In high performance multi–core chips, power and heat are predominant constraints. High performance massive multicore systems suffer from thermal hotspots, exacerbating the problem of reliability in deep submicron technologies. High power consumption not only increases the chip temperature but also jeopardizes the integrity of the system. Hence, there is a need to explore holistic power and thermal optimization and management strategies for massive on–chip multi–core environments. In multi–core environments, the communication fabric plays a major role in deciding the efficiency of the system. In multi–core processor chips this communication infrastructure is predominantly a Network–on–Chip (NoC). Tradition NoC designs incorporate planar interconnects as a result these NoCs have long, multi–hop wireline links for data exchange. Due to the presence of multi–hop planar links such NoC architectures fall prey to high latency, significant power dissipation and temperature hotspots. Networks inspired from nature are envisioned as an enabling technology to achieve highly efficient and low power NoC designs. Adopting wireless technology in such architectures enhance their performance. Placement of wireless interconnects (WIs) alters the behavior of the network and hence a random deployment of WIs may not result in a thermally optimal solution. In such scenarios, the WIs being highly efficient would attract high traffic densities resulting in thermal hotspots. Hence, the location and utilization of the wireless links is a key factor in obtaining a thermal optimal highly efficient Network–on–chip. Optimization of the NoC framework alone is incapable of addressing the effects due to the runtime dynamics of the system. Minimal paths solely optimized for performance in the network may lead to excessive utilization of certain NoC components leading to thermal hotspots. Hence, architectural innovation in conjunction with suitable power and thermal management strategies is the key for designing high performance and energy–efficient multicore systems. This work contributes at exploring various wired and wireless NoC architectures that achieve best trade–offs between temperature, performance and energy–efficiency. It further proposes an adaptive routing scheme which factors in the thermal profile of the chip. The proposed routing mechanism dynamically reacts to the thermal profile of the chip and takes measures to avoid thermal hotspots, achieving a thermally efficient dynamically reconfigurable network on chip architecture

A survey of recent contributions of high performance NoC architectures

The Network-on-Chip (NoC) paradigm has been herald as the solution to the communication limitation that System-On-Chip (SoC) poses. However, power consumption is one of its major defects. To ensure that a high performance architecture is constructed, analyzing how power can be reduced in each area of the network is essential. Power dissipation can be reduced by adjustments to the routers, the architecture itself and the communication links. In this paper, a survey is conducted on recent contributions and techniques employed by researchers towards the reduction of power in the router architecture, network architecture and communication links