abstract: In recent years we have witnessed a shift towards multi-processor system-on-chips (MPSoCs) to address the demands of embedded devices (such as cell phones, GPS devices, luxury car features, etc.). Highly optimized MPSoCs are well-suited to tackle the complex application demands desired by the end user customer. These MPSoCs incorporate a constellation of heterogeneous processing elements (PEs) (general purpose PEs and application-specific integrated circuits (ASICS)). A typical MPSoC will be composed of a application processor, such as an ARM Coretex-A9 with cache coherent memory hierarchy, and several application sub-systems. Each of these sub-systems are composed of highly optimized instruction processors, graphics/DSP processors, and custom hardware accelerators. Typically, these sub-systems utilize scratchpad memories (SPM) rather than support cache coherency. The overall architecture is an integration of the various sub-systems through a high bandwidth system-level interconnect (such as a Network-on-Chip (NoC)). The shift to MPSoCs has been fueled by three major factors: demand for high performance, the use of component libraries, and short design turn around time. As customers continue to desire more and more complex applications on their embedded devices the performance demand for these devices continues to increase. Designers have turned to using MPSoCs to address this demand. By using pre-made IP libraries designers can quickly piece together a MPSoC that will meet the application demands of the end user with minimal time spent designing new hardware. Additionally, the use of MPSoCs allows designers to generate new devices very quickly and thus reducing the time to market. In this work, a complete MPSoC synthesis design flow is presented. We first present a technique \cite{leary1_intro} to address the synthesis of the interconnect architecture (particularly Network-on-Chip (NoC)). We then address the synthesis of the memory architecture of a MPSoC sub-system \cite{leary2_intro}. Lastly, we present a co-synthesis technique to generate the functional and memory architectures simultaneously. The validity and quality of each synthesis technique is demonstrated through extensive experimentation. / Dissertation/Thesis / Ph.D. Computer Science 2013

The computer engineering group at Linköping University has parts of their research dedicated to networks-on-chip and components used in network components and terminals. This research has among others resulted in the SoCBUS NOC and a flow based network protocol processor. The main objective of this project was to integrate these components into an IP router with two or more Gigabit Ethernet interfaces. A working system has been designed and found working. It consists of three main components, the input module, the output module and a packet buffer. Due to the time constraint and the size of the project the packet buffer could not be designed to be as efficient as possible, thus reducing the overall performance. The SoCBUS also has negative impact on performance, although this could probably be reduced with a revised system design. If such a project is carried out it could use the input and output modules from this project, which connect to SoCBUS and can easily be integrated with other packet buffers and system designs.

Physical constrains of integrated circuits (commonly called chip) in regards to size and finite number of wires, has made the design of System-on-Chip (SoC) more interesting to study in terms of finding better solutions for the complexity of the chip-interconnections. The SoC has hundreds of Processing Elements (PEs), and a single shared bus can no longer be acceptable due to poor scalability with the system size. Networks on Chip (NoC) have been proposed as a solution to mitigate complex on-chip communication problems for complex SoCs. They consists of computational resources in the form of PE cores and switching nodes which allow PEs to communicate with each other. In the design and development of Networks on Chip, performance modelling and analysis has great theoretical and practical importance. This research is devoted to developing efficient and cost-effective analytical tools for the performance analysis and enhancement of NoCs with m-port n-tree topology under bursty traffic. Recent measurement studies have strongly verified that the traffic generated by many real-world applications in communication networks exhibits bursty and self-similar properties in nature and the message destinations are uniformly distributed. NoC's performance is generally affected by different traffic patterns generated by the processing elements. As the first step in the research, a new analytical model is developed to capture the burstiness and self-similarity characteristics of the traffic within NoCs through the use of Markov Modulated Poisson Process. The performance results of the developed model highlight the importance of accurate traffic modelling in the study and performance evaluation of NoCs. Having developed an efficient analytical tool to capture the traffic behaviour with a higher accuracy, in the next step, the research focuses on the effect of topology on the performance of NoCs. Many important challenges still remain as vulnerabilities within the design of NoCs with topology being the most important. Therefore a new analytical model is developed to investigate the performance of NoCs with the m-port n-tree topology under bursty traffic. Even though it is broadly proved in practice that fat-tree topology and its varieties result in lower latency, higher throughput and bandwidth, still most studies on NoCs adopt Mesh, Torus and Spidergon topologies. The results gained from the developed model and advanced simulation experiments significantly show the effect of fat-tree topology in reducing latency and increasing the throughput of NoCs. In order to obtain deeper understanding of NoCs performance attributes and for further improvement, in the final stage of the research, the developed analytical model was extended to consider the use of virtual channels within the architecture of NoCs. Extensive simulation experiments were carried out which show satisfactory improvements in the throughput of NoCs with fat-tree topology and VCs under bursty traffic. The analytical results and those obtained from extensive simulation experiments have shown a good degree of accuracy for predicting the network performance under different design alternatives and various traffic conditions.

Hernández Luz, C. (2012). Addressing Manufacturing Challenges in NoC-based ULSI Designs [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16694 / Palancia

Chips with high computational power are the crux of today’s pervasive complex digital systems. Microprocessor circuits are evolving towards many core designs with the integration of hundreds of processing cores, memory elements and other devices on a single chip to sustain high performance computing while maintaining low design costs. Two decisive paradigm shifts in the semiconductor industry have made this evolution possible: (a) architectural and (b) organizational. At the heart of the architectural innovation is a scalable high speed data communication structure, the network-on-chip (NoC). NoC is an interconnect network for the glueless integration of on-chip components in the modern complex communication centric designs. In the recent days, NoC has replaced the traditional bus based architecture owing to its structured and modular design, scalability and low design cost. The organizational revolution has resulted in a globalized and collaborative supply chain with pervasive use of third party intellectual properties to reduce the time-to-market and overall design costs. Despite the advantages of these paradigm shifts, modern system-on-chips pose a plethora of security vulnerabilities. This work explores a threat model arising from a malicious NoC IP embedded with a hardware trojan affecting the resource availability of on-chip components. A rigorous simulation infrastructure is established to evaluate the feasibility and potency of such an attack. Further, a non-invasive runtime monitoring technique is proposed and thoroughly investigated to ensure the trustworthiness of a third party NoC IP with low overheads.

Physical constrains of integrated circuits (commonly called chip) in regards to size and finite number of wires, has made the design of System-on-Chip (SoC) more interesting to study in terms of finding better solutions for the complexity of the chip-interconnections. The SoC has hundreds of Processing Elements (PEs), and a single shared bus can no longer be acceptable due to poor scalability with the system size. Networks on Chip (NoC) have been proposed as a solution to mitigate complex on-chip communication problems for complex SoCs. They consists of computational resources in the form of PE cores and switching nodes which allow PEs to communicate with each other. In the design and development of Networks on Chip, performance modelling and analysis has great theoretical and practical importance. This research is devoted to developing efficient and cost-effective analytical tools for the performance analysis and enhancement of NoCs with m-port n-tree topology under bursty traffic. Recent measurement studies have strongly verified that the traffic generated by many real-world applications in communication networks exhibits bursty and self-similar properties in nature and the message destinations are uniformly distributed. NoC's performance is generally affected by different traffic patterns generated by the processing elements. As the first step in the research, a new analytical model is developed to capture the burstiness and self-similarity characteristics of the traffic within NoCs through the use of Markov Modulated Poisson Process. The performance results of the developed model highlight the importance of accurate traffic modelling in the study and performance evaluation of NoCs. Having developed an efficient analytical tool to capture the traffic behaviour with a higher accuracy, in the next step, the research focuses on the effect of topology on the performance of NoCs. Many important challenges still remain as vulnerabilities within the design of NoCs with topology being the most important. Therefore a new analytical model is developed to investigate the performance of NoCs with the m-port n-tree topology under bursty traffic. Even though it is broadly proved in practice that fat-tree topology and its varieties result in lower latency, higher throughput and bandwidth, still most studies on NoCs adopt Mesh, Torus and Spidergon topologies. The results gained from the developed model and advanced simulation experiments significantly show the effect of fat-tree topology in reducing latency and increasing the throughput of NoCs. In order to obtain deeper understanding of NoCs performance attributes and for further improvement, in the final stage of the research, the developed analytical model was extended to consider the use of virtual channels within the architecture of NoCs. Extensive simulation experiments were carried out which show satisfactory improvements in the throughput of NoCs with fat-tree topology and VCs under bursty traffic. The analytical results and those obtained from extensive simulation experiments have shown a good degree of accuracy for predicting the network performance under different design alternatives and various traffic conditions. / Libyan Ministry of Higher Education

No description available.

No description available.

No description available.

L'évolution de Systems-on-Chip (SoCs) est rapide et le nombre des processeurs augmente conduisant à la transition des les plates-formes Multi-core vers les Manycore. Dans telles plates-formes, l'architecture d'interconnexion a également décalé des bus traditionnels vers les Réseaux sur puce (NoC) afin de faire face à la mise en échelle. Les NoC permettent aux processeurs d'échanger des informations avec la mémoire et les périphériques lors de l'exécution d'une tâche et d'effectuer plusieurs communications en parallèle. Les plates-formes basées sur un NoC sont aussi présentes dans des systèmes embarqués, caractérisés par des exigences comme la prédictibilité, la sécurité et la criticité mixte. Afin de fournir telles fonctionnalités dans les plates-formes commerciales existantes, il faut prendre en considération le NoC qui est un élément clé ayant un impact important sur les performances d'un SoC. Une tâche échange des informations à travers du NoC et par conséquent, son temps d'exécution dépend du temps de transmission des flux qu'elle génère. En calculant le temps de transmission de pire cas (WCTT) des flux dans le NoC, une étape est faite vers le calcul du temps d'exécution de pire cas (WCET) d'une tâche. Ceci contribue à la prédictibilité globale du système. De plus, en prenant en compte les politiques d'arbitrage dans le NoC, il est possible de fournir des garanties de sécurité contre des tâches compromises qui pourraient essayer de saturer les ressources du système (attaque DoS). Dans les systèmes critiques de sécurité, une distinction des tâches par rapport à leur niveau de criticité, permet aux tâches de criticité mixte de coexister et d'exécuter en harmonie. De plus, ça permet aux tâches critiques de maintenir leurs temps d'exécution au prix de tâches de faible criticité qui seront ralenties ou arrêtées. Cette thèse vise à fournir des méthodes et des mécanismes dans le but de contribuer aux axes de prédictibilité, de sécurité et de criticité mixte dans les architectures Manycore basées sur Noc. En outre, l'incitation consiste à relever conjointement les défis dans ces trois axes en tenant compte de leur impact mutuel. Chaque axe a été étudié individuellement, mais très peu de recherche prend en compte leur interdépendance. Cette fusion des aspects est de plus en plus intrinsèque dans des domaines tels que Internet-of-Things, Cyber-Physical Systems (CPS), véhicules connectés et autonomes qui gagnent de l'élan. La raison en est leur haut degré de connectivité qui crée une grande surface d'exposition ainsi que leur présence croissante qui rend l'impact des attaques sévère et visible. Les contributions de cette thèse consistent en une méthode pour fournir une prédictibilité aux flux dans le NoC, un mécanisme pour la sécurité du NoC et une boîte à outils pour la génération de trafic utilisée pour l'analyse comparative. La première contribution est une adaptation de l'approche de la trajectoire traditionnellement utilisée dans les réseaux avioniques (AFDX) pour calculer le WCET. Dans cette thèse, nous identifions les différences et les similitudes dans l'architecture NoC et modifions l'approche de la trajectoire afin de calculer le WCTT des flux NoC. La deuxième contribution est un mécanisme qui permet de détecter les attaques de DoS et d'atténuer leur impact dans un ensemble des flux de criticité mixte. Plus précisément, un mécanisme surveille le NoC et lors de la détection d'un comportement anormal, un deuxième mécanisme d'atténuation s'active. Ce dernier applique des limites de trafic à la source et restreint le taux auquel le NoC est occupé. Cela atténuera l'impact de l'attaque, garantissant la disponibilité des ressources pour les tâches de haute criticité. Finalement NTGEN, est un outil qui peut générer automatiquement des jeux des flux aléatoires mais qui provoquent une occupation NoC prédéterminée. Ces ensembles sont ensuite injectés dans le NoC et les informations sont collectées en fonction de la latence / The evolution of Systems-on-Chip (SoCs) is rapid and the number of processors has increased transitioning from Multi-core to Manycore platforms. In such platforms, the interconnect architecture has also shifted from traditional buses to Networks-on-Chip (NoC) in order to cope with scalability. NoCs allow the processors to exchange information with memory and peripherals during task execution and enable multiple communications in parallel. NoC-based platforms are also present in embedded systems, characterized by requirements like predictability, security and mixed-criticality. In order to enable such features in existing commercial platforms it is necessary to take into consideration the NoC which is a key element with an important impact to a SoC's performance. A task exchanges information through the NoC and as a result, its execution time depends on the transmission time of the flows it generates. By calculating the Worst Case Transmission Time (WCTT) of flows in the NoC, a step is made towards the calculation of the Worst Case Execution Time (WCET) of a task. This contributes to the overall predictability of the system. Similarly by leveraging arbitration and traffic policies in the NoC it is possible to provide security guarantees against compromised tasks that might try to saturate the system's resources (DoS attack). In safety critical systems, a distinction of tasks in relation to their criticality level, allows tasks of mixed criticality to co-exist and execute in harmony. In addtition, it allows critical tasks to maintain their execution times at the cost of tasks of lower criticality that will be either slowed down or stopped. This thesis aims to provide methods and mechanisms with the objective to contribute in the axes of predictability, security and mixed criticality in NoC-based Manycore architectures. In addition, the incentive is to jointly address the challenges in these three axes taking into account their mutual impact. Each axis has been researched individually, but very little research takes under consideration their interdependence. This fusion of aspects is becoming more and more intrinsic in fields like the Internet-of-Things, Cyber-Physical Systems (CPSs), connected and autonomous vehicles which are gaining momentum. The reason being their high degree of connectivity which is creates great exposure as well as their increasing presence which makes attacks severe and visible. The contributions of this thesis consist of a method to provide predictability to a set of flows in the NoC, a mechanism to provide security properties to the NoC and a toolkit for traffic generation used for benchmarking. The first contribution is an adaptation of the trajectory approach traditionally used in avionics networks (AFDX) to calculate WCET. In this thesis, we identify the differences and similarities in NoC architecture and modify the trajectory approach in order to calculate the WCTT of NoC flows. The second contribution is a mechanism that detects DoS attacks and mitigates their impact in a mixed criticality set of flows. More specifically, a monitor mechanism will detect abnormal behavior, and activate a mitigation mechanism. The latter, will apply traffic shaping at the source and restrict the rate at which the NoC is occupied. This will limit the impact of the attack, guaranteeing resource availability for high criticality tasks. Finally NTGEN, is a toolkit that can automatically generate random sets of flows that result to a predetermined NoC occupancy. These sets are then injected in the NoC and information is collected related to latency