Web page performance analysis

Computer systems play an increasingly crucial and ubiquitous role in human endeavour by carrying out or facilitating tasks and providing information and services. How much work these systems can accomplish, within a certain amount of time, using a certain amount of resources, characterises the systems’ performance, which is a major concern when the systems are planned, designed, implemented, deployed, and evolve. As one of the most popular computer systems, the Web is inevitably scrutinised in terms of performance analysis that deals with its speed, capacity, resource utilisation, and availability. Performance analyses for the Web are normally done from the perspective of the Web servers and the underlying network (the Internet). This research, on the other hand, approaches Web performance analysis from the perspective of Web pages. The performance metric of interest here is response time. Response time is studied as an attribute of Web pages, instead of being considered purely a result of network and server conditions. A framework that consists of measurement, modelling, and monitoring (3Ms) of Web pages that revolves around response time is adopted to support the performance analysis activity. The measurement module enables Web page response time to be measured and is used to support the modelling module, which in turn provides references for the monitoring module. The monitoring module estimates response time. The three modules are used in the software development lifecycle to ensure that developed Web pages deliver at worst satisfactory response time (within a maximum acceptable time), or preferably much better response time, thereby maximising the efficiency of the pages. The framework proposes a systematic way to understand response time as it is related to specific characteristics of Web pages and explains how individual Web page response time can be examined and improved

Evaluation of Strong Consistency Web Caching Techniques

The growth of the World Wide Web (WWW or Web) and its increasing use in all types of business have created bottlenecks that lead to high network and server overload and, eventually, high client latency. Web Caching has become an important topic of research, in the hope that these problems can be addressed by appropriate caching techniques. Conventional wisdom holds that strong cache consistency, with (almost) transactional consistency guarantees, may neither be necessary for Web applications, nor suitable due to its high overhead. However, as business transactions on the Web become more popular, strong consistency will be increasingly necessary. Consequently, it is important to have a comprehensive understanding of the performance behavior of these protocols. The existing studies, unfortunately, are ad hoc and the results cannot be compared across different studies. In this paper we evaluate the performance of different categories of cache consistency algorithms using a standard benchmark: TPC-W, which is the Web commerce benchmark. Our experiments show that we could still enforce strong cache consistency without much overhead, and Invalidation, as an event-driven strong cache consistency algorithm, is most suitable for online e-business. We also evaluate the optimum deployment of caches and find that proxy-side cache has a 30-35% performance advantage over client-side cache with regard to system throughput