Design Approach to Implementation Of Arbitration Algorithm In Shared Bus Architectures (MPSoC)

The multiprocessor SoC designs have more than one processor and huge memory on the same chip. SoC consists of hardware cores and software cores ,multiple processors, embedded DRAM and connectors between cores .A wide range of MPSOC architectures have been developed over the past decade. This paper surveys the history of various On-Chip communication architectures present in the design of MPSoC. This acts as a primary factor of overall performance in complex SoC designs. Some of the various techniques that have driven the design of MpSoC has been discussed. Dynamically configurable communication architectures are found to improve the system performance. Currently On-chip interconnection networks are mostly implemented using shared buses which are the most common medium. The arbitration plays a crucial role in determining performance of bus-based system, as it assigns priorities, with which processor is granted the access to the shared communication resources. In the conventional arbitration algorithms there are some drawbacks such as bus starvation problem and low system performance. The bus should provide each component a flexible and utmost share of on-chip communication bandwidth and should improve the latency in access of the shared bus. The performance of SoC is improved using the probabilistic round robin algorithm with regard to the parameters, latency.Thus in this paper various issues related to bus arbitration related to design of MPSoC is analysed

Scalable Resource Control in Active Networks

The increased complexity of the service model relative to store-and-forward routers has made resource management one of the paramount concerns in active networking research and engineering. In this paper,we address two major challenges in scaling resource management-to-many-node active networks. The first is the use of market mechanisms and trading amongst nodes and programs with varying degrees of competition and cooperation to provide a scalable approach to managing active network resources. The second is the use of a trust-management architecture to ensure that the participants in the resource management marketplace have a policy-driven "rule of law" in which marketplace decisions can be made and relied upon. We have used lottery scheduling and the Keynote trust-management system for our implementation, for which we provide some initial performance indications

Performance Tuning of Dual-priority Delta Networks through Queuing Scheduling Disciplines

Differentiated Services (DiffServ) and other scheduling strategies are now widespread in the traditional, “best effort” Internet. These Internet Architectures offer Quality of Service (QoS) guarantees for important customers at the same time as supporting less critical applications of lower priority. Strict priority queuing (PQ), weighted round robin (WRR), and class-based weighted fair queuing (CBWFQ) are three common scheduling disciplines for differentiation of services in telecommunication networks. In this paper, a comparative performance study of the above PQ, WRR and CBWFQ queuing scheduling policies applied on a double-buffered, 6-stage Multistage Interconnection Network (MIN) that natively supports a 2-class priority mechanism is presented and analyzed using simulation experiments. We also consider a 10-stage MIN, to validate that the conclusions drawn from the 6-stage MIN apply to MINs of different sizes. The findings of this paper can be used by MIN designers to optimally configure their networks

Decentralising resource management in operating systems

This dissertation explores operating system mechanisms to allow resource-aware applications to be involved in the process of managing resources under the premise that these applications (1) potentially have some (implicit) notion of their future resource demands and (2) can adapt their resource demands. The general idea is to provide feedback to resource-aware applications so that they can proactively participate in the management of resources. This approach has the benefit that resource management policies can be removed from central entities and the operating system has only to provide mechanism. Furthermore, in contrast to centralised approaches, application specific features can be more easily exploited. To achieve this aim, I propose to deploy a microeconomic theory, namely congestion or shadow pricing, which has recently received attention for managing congestion in communication networks. Applications are charged based on the potential "damage" they cause to other consumers by using resources. Consumers interpret these congestion charges as feedback signals which they use to adjust their resource consumption. It can be shown theoretically that such a system with consumers merely acting in their own self-interest will converge to a social optimum. This dissertation focuses on the operating system mechanisms required to decentralise resource management this way. In particular it identifies four mechanisms: pricing & charging, credit accounting, resource usage accounting, and multiplexing. While the latter two are mechanisms generally required for the accurate management of resources, pricing & charging and credit accounting present novel mechanisms. It is argued that congestion prices are the correct economic model in this context and provide appropriate feedback to applications. The credit accounting mechanism is necessary to ensure the overall stability of the system by assigning value to credits

Towards Multi-Service Traffic Shaping in Two-Tier Enterprise Data Centers

International audienceIn Enterprise Data Centers (EDC), service providers are usually governed by Client Service Contracts (CSC) that specify, among other requirements, the rate at which a service should be accessed. The contract limits the rate to no more than a number of service requests during a given observation period. In two-tier setups, a cluster of Service-Oriented Networking (SON) Appliances form a pre-processing tier that accesses services in the service tier. SON Appliances locally shape the flow of requests to enforce the global rate defined in the CSC. Off-the-shelf SON Appliances present architectural limitations that prevent them from being used to efficiently perform traffic shaping in the presence of multiple service hosts. In this paper, besides identifying these limitations, we provide two contributions in this field. First, we introduce a SON Appliance architecture fit for multi-service traffic shaping. Second, we propose and validate an algorithm for multipoint-to-multipoint service traffic shaping in two-tier EDCs. We show via simulation that our approach solves the multipoint-to-multipoint service traffic shaping problem while pushing the system to its maximum capacity

Lottery and stride scheduling : flexible proportional-share resource management

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 145-151).by Carl A. Waldspurger.Ph.D

Cyber Security Evaluation of CentOS Red Hat Based Operating System Under Cyber Attack with Increasing Magnitude

The increasing interest in ‘always-connected’ devices and the Internet of Things has led to electronic devices with Internet connectivity becoming a staple in modern household and workplace. Consequently, this increase has also led to an increase in vulnerable devices, ripe for hijacking by a malicious third party. Distributed Denial of Service (DDoS) attacks have consistently been an issue since the birth of the Internet. With the large number of devices available today, the strength and consistency of these attacks has only grown and will continue to grow. Since, depending on certain variables, these DDoS attacks can effectively render a target system inoperable, precautions must be taken in order to prevent these attacks. Not all devices are created equal; Many harbor flaws that allow them to be used by a separate, malicious host without the knowledge of the owner. There is a myriad of devices on the market today, any of which can be used in a network of zombie machines meant to carry out an attack, a botnet. These botnets are used to flood a system with information, ideally consuming large amounts of resources, such as memory or processing power. If the attack is successful, operation within the target system is effectively halted, often for long periods of time in the more severe attacks. Just like the variety in devices, there is a variety in the software that operates these devices. In this experiment, I focus efforts on comparing the ability of CentOS 15 with Windows Server 2012R to function under attack. I analyze four popular DDoS attacks using simulated network traffic consisting of botnets ranging from of over 16 million systems, 65 thousand systems and 254 systems in a controlled, closed environment

MANAGING QUERY AND UPDATE TRANSACTIONS UNDER QUALITY CONTRACTS IN WEB-DATABASES

In modern Web-database systems, users typically perform read-only queries, whereas all write-only data updates are performed in the background, concurrently with queries.For most of these services to be successful and their users to be kept satisfied, two criteria need to be met: user requests must be answered in a timely fashion and must return fresh data. This is relatively easy when the system is lightly loaded and, as such, both queries and updates can be executed quickly. However, this goal becomes practically hard to achieve in real systems due to the high volumes of queries and updates, especially in periods of flash crowds. In this work, we argue it is beneficial to allow users to specify their preferences and let the system optimize towards satisfying user preferences, instead of simply improving the average case. We believe that this user-centric approach will empower the system to gracefully deal with a broader spectrum of workloads.Towards user-centric web-databases, we propose a Quality Contracts framework to help users express their preferences over multiple quality specifications. Moreover, we propose a suite of algorithms to effectively perform load balancing and scheduling for both queries and updates according to user preferences. We evaluate the proposed framework and algorithms through a simulation with real traces from disk accesses and from a stock information website. Finally, to increase the applicability of Quality Contracts enhanced Web-database systems, we propose an algorithm to help users adapt to the Web-database system behavior and maximize their query success ratio