Performance Comparison of Various Garbage Collectors on JVM for Web Services

The current demand of e-commerce has increased the requirement of efficiency on Java server-side applications. Hence, the continuous availability and the good response-time of the Java virtual machine are needed to satisfy the continuous incoming request from remote clients. This project studied the optimization of garbage collector in Java virtual machine particularly on 3-tier Java server-side application to increase the throughput of real times processing, full utilization of CPU time and more memory efficiency to handle more workloads. The characteristics and the architectures of five JikesRVM garbage collectors were studied. They are CopyMS, GenMS, SemiSpace, GenCopy and MarkSweep. The best performing garbage collectors was determined and the main causes of their overheads were identified. The benchmarking suite, SPECjbb2000 was used to emulate a 3-tier Java server-side application. The performance of the five different garbage collectors on SPECjbb2000 for large and small memory size was compared. In conclusion, CopyMS is found to have the best average throughput for large heap size whereas, GenMS has the best overall performance in memory constraint and can handle the most workloads. On the other hand, GenCopy and SemiSpace demonstrated higher efficiency in handling light workloads. The performance of garbage collectors is proportional to the heap size used. Memory fragmentation and long pause time are two main challenges to be overcome for increasing the application performance. Future works for optimizing garbage collectors are recommended at the end of this report