Research And Implementation Of High Concurrency Load Generating System Based On MPI

Load testing is the most important way to assess the QOS (Quality of Service) ofweb applications, and load testing system is needed to generate mass concurrentrequests. With the help of cloud computing technology, the performance of modern webapplications has been raise to a higher level. Traditional load generate methods are notcapable of load testing modern web applications anymore.Multi-threaded is the most popular load generate method which is used by manyopen-source or commercial load testing systems. But a significant weakness of multi-threaded is low request concurrency. Since multi-threaded based system is usingblocking I/O to handle TCP connections, more threads must be created as requestconcurrency grows, and as we all know, context switches of threads is a costly operation.Asynchronous I/O is a more effective way of generating concurrent requests since ituses non-blocking I/O and only one thread is needed to handle all the TCP connections.But the problem is, asynchronous I/O based load testing systems are not making gooduse of all the CPU cores. The idea of using all the CPU cores in asynchronous I/O basedsystem has been proposed by some researchers but few of them has proved that usingmultiple CPU cores is really improving the performance of load testing systems as theyare not CPU-intensive applications.On the other hand, scalability of load testing system is becoming increasinglyimportant, therefore improving the scalability of load testing system has become animportant research directions of high concurrent load generation.In this article, we review the existing research and studies on high concurrency loadgenerating system and load testing system, figure out the basic ideas of existing methods and find out the problems of these systems. On the basis of existing researchworks, we propose the design of an MPI based load testing system PBench, whichgenerates concurrent load in parallel, either in multi-core or distributed environment.PBench is capable of using all CPU cores to improve the performance of loadgenerating. Besides, PBench can also be run on multiple computers connected by LAN,and improve load concurrency, which means PBench is equipped with high scalability.The design and implement of PBench is expound in this article, furthermore,comparative experiment results showed that our proposed design is capable ofimproving the performance of load testing system.