| 1. |
- Carlsson, Niklas, et al.
(författare)
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Had You Looked Where Im Looking? Cross-user Similarities in Viewing Behavior for 360 degrees Video and Caching Implications
- 2020
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Ingår i: PROCEEDINGS OF THE ACM/SPEC INTERNATIONAL CONFERENCE ON PERFORMANCE ENGINEERING (ICPE20). - New York, NY, USA : ASSOC COMPUTING MACHINERY. - 9781450369916 ; , s. 130-137
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Konferensbidrag (refereegranskat)abstract
- The demand and usage of 360 degrees video services are expected to increase. However, despite these services being highly bandwidth intensive, not much is known about the potential value that basic bandwidth saving techniques such as server or edge-network on-demand caching (e.g., in a CDN) could have when used for delivery of such services. This problem is both important and complicated as client-side solutions have been developed that split the full 360 degrees view into multiple tiles, and adapt the quality of the downloaded tiles based on the users expected viewing direction and bandwidth conditions. To better understand the potential bandwidth savings that caching-based techniques may offer for this context, this paper presents the first characterization of the similarities in the viewing directions of users watching the same 360 degrees video, the overlap in viewports of these users (the area of the full 360 degrees view they actually see), and the potential cache hit rates for different video categories and network conditions. The results provide substantial insight into the conditions under which overlap can be considerable and caching effective, and can inform the design of new caching system policies tailored for 360 degrees video.
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| 2. |
- Hashemian, Raoufehsadat, et al.
(författare)
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Contention AwareWeb of Things Emulation Testbed
- 2020
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Ingår i: PROCEEDINGS OF THE ACM/SPEC INTERNATIONAL CONFERENCE ON PERFORMANCE ENGINEERING (ICPE20). - : ASSOC COMPUTING MACHINERY. - 9781450369916 ; , s. 246-256
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Konferensbidrag (refereegranskat)abstract
- Since the advent of the Web, new Web benchmarking tools have frequently been introduced to keep up with evolving workloads and environments. The introduction of Web of Things (WoT) marks the beginning of another important paradigm that requires new benchmarking tools and testbeds. Such a WoT benchmarking testbed can enable the comparison of different WoT application configurations and workload scenarios under assumptions regarding WoT application resource demands and WoT device network characteristics. The powerful computational capabilities of modern commodity multicore servers along with the limited resource consumption footprints of WoT devices suggest the feasibility of a benchmarking testbed that can emulate the application behaviour of a large number of WoT devices on just a single multicore server. However, to obtain test results that reflect the true performance of the system being emulated, care must be exercised to detect and consider the impact of testbed bottlenecks on performance results. For example, if too manyWoT devices are emulated then performance metrics obtained from a test run, e.g., WoT device response times, would only reflect contention among emulated devices for shared multicore server resources instead of providing a true indication of the performance of the WoT system being emulated. We develop a testbed that helps a user emulate a system consisting of multiple WoT devices on a single multicore server by exploiting Docker containers. Furthermore, we devise a novel mechanism for the user to check whether shared resource contention in the testbed has impacted the integrity of test results. Our solution allows for careful scaling of experiments and enables resource efficient evaluation of a wide range of WoT systems, architectures, application characteristics, workload scenarios, and network conditions.
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| 3. |
- Le Duc, Thang, 1980-, et al.
(författare)
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Workload Diffusion Modeling for Distributed Applications in Fog/Edge Computing Environments
- 2020
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Ingår i: ICPE '20. - New York : Association for Computing Machinery (ACM). - 9781450369916 ; , s. 218-229
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the problem of workload generation for distributed applications in fog/edge computing. Unlike most existing work that tends to generate workload data for individual network nodes using historical data from the targeted node, this work aims to extrapolate supplementary workloads for entire application / infrastructure graphs through diffusion of measurements from limited subsets of nodes. A framework for workload generation is proposed, which defines five diffusion algorithms that use different techniques for data extrapolation and generation. Each algorithm takes into account different constraints and assumptions when executing its diffusion task, and individual algorithms are applicable for modeling different types of applications and infrastructure networks. Experiments are performed to demonstrate the approach and evaluate the performance of the algorithms under realistic workload settings, and results are validated using statistical techniques.
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| 4. |
- Nylander, Tommi, et al.
(författare)
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Modeling of Request Cloning in Cloud Server Systems using Processor Sharing
- 2020
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Ingår i: Proceedings of the 2020 ACM/SPEC International Conference on Performance Engineering. - New York, NY, USA : ACM. - 9781450369916 ; , s. 24-35
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Konferensbidrag (refereegranskat)abstract
- The interest for studying server systems subject to cloned requests has recently increased. In this paper we present a model that allows us to equivalently represent a system of servers with cloned requests, as a single server. The model is very general, and we show that no assumptions on either inter-arrival or service time distributions are required, allowing for, e.g., both heterogeneity and dependencies. Further, we show that the model holds for any queuing discipline. However, we focus our attention on Processor Sharing, as the discipline has not been studied before in this context.The key requirement that enables us to use the single server G/G/1 model is that the request clones have to receive synchronized service. We show examples of server systems fulfilling this requirement. We also use our G/G/1 model to co-design traditional load-balancing algorithms together with cloning strategies, providing well-performing and provably stable designs.Finally, we also relax the synchronized service requirement and study the effects of non-perfect synchronization. We derive bounds for how common imperfections that occur in practice, such as arrival and cancellation delays, affect the accuracy of our model. We empirically demonstrate that the bounds are tight for small imperfections, and that our co-design method for the popular Join-Shortest-Queue (JSQ) policy can be used even under relaxed synchronization assumptions with small loss in accuracy.
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