An operating system needs to fairly allocate shared hardware resources among different applications, and Linux uses Completely Fair Scheduler (CFS) to achieve this goal. To ensure fairness, CFS implements bandwidth control that sets the maximum limit on the resources that a process can use. Setting the upper limit helps CFS to discover badly behaving applications and hard cap them to limit the overall damage to the system and other applications, thereby improving fairness.We observe that, in an effort to ensure fairness, the bandwidth control can unnecessarily throttle processes which results in poor application performance. We investigate the root cause of this limitation and discover that the CPU runtime accounting mechanism of bandwidth control, which tracks if a process has reached it maximum allocated limit, is responsible for it. We also find that the overhead of fair resource allocation in bandwidth control can become significantly high due to the way it is implemented. We propose mechanisms to reduce throttling as well as the overhead. Our experimental results show that the proposed techniques are able to eliminate nearly all throttling, thus providing up to 12% performance gain. Also, our approach reduces the bandwidth control overhead by up to 24x.
Mobile Ad-hoc Networks (MANETs) find numerous applications. Its utility can be extended by integrating it with Internet. Some real-life applications where such integrated networks can be used are disaster situation viz., earthquake, battle fields etc. MANETs are dynamic topology, infrastructure less and standalone networks of wireless mobile nodes. To overcome this limitation, MANET needs to connect to the Internet. In such networks, mobile nodes do not have wired connection, so they do not follow any particular route to transfer their packets. Thus, every time when topology changes, routing paths changes too. However, every node selects the shortest path to route their packet. In that case, this path will be congested due to overload. We propose a load balancing adaptive Internet gateway discovery approach which focuses on solving the problem of overload and congestion in mobile ad-hoc domain. Particle Swarm Optimization is used for selecting an optimal path among all paths available. Our work is to optimize this load balancing problem. We are using Particle Swarm Optimization (PSO) concept to overcome this problem. In our approach, we use soft computing technique viz., working procedure of PSO algorithm which searches the optimal paths using some mathematical function. Then, we combine shortest path algorithm with the gateway discovery algorithm. Thus, the algorithm first selects the shortest path stored in the memory and check whether it is free for routing packets or not, if the route is free or lightly loaded, then the source node will transfer packets otherwise if the node is overloaded, then PSO searches for the next optimal neighbour or node to route the packet. The new path is selected to route packets and stored in the place of current available path. Proposed algorithm has been implemented in MATLAB. Our approach outperforms the existing approaches.
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