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A lack of energy proportionality, low resource utilization, and interference in virtualized infrastructure make the cloud a challenging target environment for improving energy efficiency. In this paper we present OptiBook, a system that improves energy proportionality and/or resource utilization to optimize performance and energy efficiency. OptiBook shares servers between latency-sensitive services...
Modern software-intensive systems must often guarantee certain quality requirements under changing run-time conditions and high levels of uncertainty. Self-adaptation has proven to be an effective way to engineer systems that can address such challenges, but many of these approaches are purely reactive and adapt only after a failure has taken place. To overcome some of the limitations of reactive...
The recent growth of interest for in-memory databases poses the question on whether established prediction methods such as response surfaces and simulation are effective to describe the performance of these systems. In particular, the limited dependence of in-memory technologies on the disk makes methods such as simulation more appealing than in the past, since disks are difficult to simulate. To...
As modern service systems are pressured to provide competitive prices via cost-effective capacity planning, especially in the paradigm of cloud computing, service level agreements (SLAs) end up becoming ever more sophisticated, i.e., fulfilling targets of different percentiles of response times. However, it is no mean feat to predict even the average response times of real systems, or even abstracted...
Research studies have shown that the effectiveness of collaboration and the choice of communication modality is intricately linked with the perceived presence and availability of the collaborating parties. Most collaboration systems offer users the ability to publish their presence for effective collaboration. However, a close observation of users' behavioral data shows a divergence such as in a published...
As Applications are moved from physical servers to virtual machines sharing storage resources, they experience large variation in I/O latencies. While maintaining average performance in such virtualized environments is important to conform to service level agreements (SLA), cloud users also expect their applications to have minimum variation in tail end latencies like 90th percentile latency for predictable...
Modern Internet applications are subject to significant variations in workload demand and this may affect the applications performance. Such kind of applications are usually hosted on multi-tiered, cluster based web hosting environments. Dynamic resource allocation play a curial role in handling sudden events where servers are moved from another (quieter) pool to meet such demand. In this work two...
We developed a new task scheduling technique that improves the response times of Web applications. Most of the high-performance processors used in today's servers support thread-level parallelism with multiple hardware threads within each core using Simultaneous Multi-Threading (SMT). SMT capabilities can improve the peak throughput of a server by increasing the utilization of the computing resources...
Website response time is one of the most important performance parameter of website. It can be used to assess website performance to forecast the status of website. Large amounts of data are applied by a distributed monitoring system that monitoring a university website response time. Support vector machine with information granulation is studied to predict the response time. It can predict accurately...
In a typical database application development, requirement is to optimize SQL queries to meet service level agreements (SLA); the optimized queries are tested on the application development database which is some fraction of the production database. As time progresses the database grows and the earlier optimized queries may not hold SLA anymore. Once the application is launched and deployed, it becomes...
The performance and scalability of centralized network storage systems cannot follow the processing needs of rapid growing data. Using large-capacity client caches is one of the solutions. This paper points out that the efficiency of "data exchange" between phases is the most important problem in managing large-capacity cache. And then, it defines Stable Set Model (SSM), which can characterize...
We model and evaluate the performance of a distributed key-value storage system that is part of the Spotify backend. Spotify is an on-demand music streaming service, offering low-latency access to a library of over 16 million tracks and serving over 10 million users currently. We first present a simplified model of the Spotify storage architecture, in order to make its analysis feasible. We then introduce...
The Web service (WS) paradigm is an emerging approach to building Web applications, in which software designers typically build new WSs by leveraging existing, third-party WSs. Understanding performance characteristics of third party WSs is critical to the overall system performance. Although such performance evaluation can be done through testing of third party WSs, it is quite an expensive process...
Multi-step ahead response time prediction of CPU constrained computing systems is vital for admission control, overload protection and optimization of resource allocation in these systems. CPU constrained computing systems such as web servers can be modeled as single server queuing systems. These systems are stochastic and nonlinear. Thus, a well-designed nonlinear prediction scheme would be able...
Currently the QoS requirements for disk-based storage systems are usually presented in the form of service-level agreement (SLA) to bound I/O measures such as latency and throughput of I/O requests. However, SLA is not an effective performance interface for users to specify their required I/O service quality for two major reasons. First, for users, it is difficult to determine appropriate latency...
The automatic allocation of enterprise workload to resources can be enhanced by being able to make `what-if' response time predictions, whilst different allocations are being considered. It is important to quantitatively compare the effectiveness of different prediction techniques for use in cloud infrastructures. To help make the comparison of relevance to a wide range of possible cloud environments...
This paper advocates for the introduction of performance awareness in autonomic systems. The motivation is to be able to predict the performance of a target configuration when a self-* feature is planning a system reconfiguration.We propose a global and partially automated process based on queues and queuing networks models. This process includes decomposing a distributed application into black boxes,...
In the last few years, the paradigms used to create new business applications is deeply changed. As matter of fact, the service providers turned their old approach create from scratch whatever we need into a new one: look for and integrate. In this brand new scenario, the key role is played by the interoperability: indeed it is required that each time a new service is deployed and once the interfaces...
Predicting application is used by an enterprise is a power tool to inform and guide our decision making to keep our products and services competitive. This paper briefly introduces the related knowledge and terminology for data mining and analyzes how to build data mining application for predicting. This paper provides examples to answer business problem by data mining, and broadly outlines the approach...
In recent years, Session Initiation Protocol (SIP) based Voice over IP (VoIP) based applications are alternative to the traditional Public Switched Telephone Networks (PSTN) because of its flexibility in the implementation of new features and services. The Session Initiation Protocol (SIP) is becoming a popular signaling protocol for Voice over IP (VoIP) based applications. The SIP Proxy server is...
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