Web Performance Testing Model

Driving by market demand, Web application has nowadays been developed into a large-scale platform for e-commerce, information release and service supply from general website. The software size is expanding and software complexity increasing. However, software development cycle is shortened by fierce business competition. How to guarantee accuracy and reliability becomes a focused question. As an important way of guaranteeing the quality and reliable of software, the testing of Web applications becomes an important field in software developing. The testing of Web application system includes function test, performance test, security test, etc. Performance test is especially important for performance reflects directly the service quality supplied by Web. Meanwhile, the number of Web users and its date transmission rate are always changing, that this dynamic character becomes the main problem in the developing of Web applications.Recently, research institutes in and abroad have done lots of researches on performance test of Web application software, presented some performance approaches and developed many testing tools. Among the performance test approaches, relevantly mature ones are virtual user method, WUS method and object-driving method with each one has its own emphasis point. Virtual user method exerts pressure on testing program by imitating behaviors of real users; WUS method aims at establishing real test scenarios; object-driving method emphasizes on testing the making-up objects of Web. There is no research on choice and optimization of test strategies of Web performance test, however, choosing test strategy correctly is significant for promoting performance test efficiency.In this article, based on the analysis of existing performance test models and combines software cybernetics, we has presented a feedback control model of Web performance test with the purpose of finding out an optimal performance test strategy to achieve the performance test goal with minimized cost. Feedback control model of Web performance test apply controlled Markov chain to describe. It decomposes the test process into different states. Test strategy drives test process to transfer from one state to another. Different test strategy will generate different states. Choose the best strategy to make test process converge to target state quickly then finish test. This article focuses on the performance test models and shall reach the works as follows:(1) The application of feedback control principle in performance test. Based on the analysis of characteristics of existing performance test approaches and combines the principle of feedback control principle, this article demonstrates how to combine feedback test information with test strategy.(2) The establishment of feedback control model of Web performance test. This article demonstrates how to describe model and abstracted it with controlled Markov chain; considers designing an optimal test strategy to avoid computational complexity, meanwhile to take the advantage of characteristics of Web performance test.(3) Software phantom. This article analyzes open source test tool JMeter and Web service software Apache, combines feedback control model of Web performance test idea then simulates model by does appropriate revisions and add modules to JMeter and Apache.This article has traced the updated research results of performance test approaches and development of test tools in and abroad, and then combines the idea of software cybernetics to develop the feedback control model of Web performance test. The main research results include:(1) Use controlled Markov chain to describe the Web performance test models. Markov chain is the discrete time stochastic process in mathematics that owns the property of Markov. During the research, Web test process is decomposed into different states, system states and test strategies are abstracted to achieve the purpose of using controlled Markov chain to describe Web performance test models.(2) Core of feedback control model of Web performance-controller modeling. Controller is responsible for the choice of test strategy. The article analyzes the key factors that determine the quality of test strategy, combines the relationship of performance index and test strategy, establishes an optional model of optimal test strategy.Finally, we use the model simulation program developed to do pressure test on a Web server. The result proves that the feedback control model of Web performance can locate the peak load of the system and find out the bottleneck position quickly. It can improve the efficiency of performance test significantly.