ISEL - Eng. Elect. Tel. Comp. - Capítulos ou partes de livros
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Browsing ISEL - Eng. Elect. Tel. Comp. - Capítulos ou partes de livros by Author "Veiga, Luís"
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- Cloud-supported certification for energy-efficient web browsing and servicesPublication . Avelar, Gonçalo; Simão, José; Veiga, LuísWeb applications are increasingly pushing more computation to the end user. With the proliferation of the software-as-a-service model, major Cloud providers assume browsers as the user agent to access their solutions, taking advantage of recent and powerful web programming client-side technologies. These technologies enhance and revamp web pages’ aesthetics and interaction mechanics. Unfortunately, they lead to increasing energetic impact, proportional to the rate of appearance of more sophisticated browser mechanisms and web content. This work presents GreenBrowsing, which is composed of (i) A Google Chrome extension that manages browser resource usage and, indirectly, energy impact by employing resource-limiting mechanisms on browser tabs; (ii) A certification subsystem that ranks URL and web domains based on web page-induced energy consumption. We show that GreenBrowsing’s mechanisms can achieve substantial resource reduction, in terms of energy-inducing resource metrics like CPU usage, memory usage and variation, up to 80%, for CPU and memory usage. It is also, indirectly and partially, able to reduce bandwidth usage when employing a specific subset of the mechanisms presented. All this is with limited degradation of user experience when compared to browsing the web without the extension.
- A Taxonomy of adaptive resource management mechanisms in virtual machines: recent progress and challengesPublication . Simão, José; Veiga, LuísCloud infrastructures make extensive use of hypervisors (e.g., Xen, ESX), containers (e.g., LXC), and high-level virtual machines (e.g., CLR, Java), broadly known as virtual machine (VM) technologies, to achieve workload isolation and efficient resource management. Isolation is a static mechanism that relies on hardware or operating system support to be enforced. Resource management is dynamic, and VMs must self-adapt or be instructed to adapt in order to fit their guest’s needs. In this chapter, we review the main approaches for adaptation and monitoring in virtual machines deployments, their tradeoffs, and their main mechanisms for resource management. We frame them into an adaptation loop where sensors are monitored (e.g., page utilization), decisions are made (e.g., if-else rule, proportional-integral-derivative controller), and actions are performed using actuators (e.g., share page, change heap size). As is common in systems research, improvement in one property is accomplished at the expense of some other property. So, we present a taxonomy that, when applied to different solutions that use or augment virtual machines, can help visually in determining their similarities and differences. We analyze adaptability in virtual machines using three seemingly orthogonal characteristics: responsiveness (R), comprehensiveness (C), and intricateness (I). The process of classification and comparing systems is detailed, and several representative state of the art systems are evaluated.