[DeveloperWorks] JVM updates in WebSphere Application Server V8: Adaptive spinning and the lock nursery

JVM updates in WebSphere Application Server V8: Adaptive spinning and the lock nursery


Summary:
This article introduces refinements to concurrency-related optimizations available in the Java™ Virtual Machine shipped with IBM® WebSphere® Application Server V8. As these optimizations are related to synchronization between threads, this discussion begins with a short introduction to synchronization concepts within the JVM, as well as existing optimizations, and then introduces two new refinements that can help to reduce memory and CPU consumption within the JVM. This content is part of the IBM WebSphere Developer Technical Journal.

Introduction

One of the advantages of Java is its native support for threading and concurrency. While it is best to avoid synchronization between threads whenever possible, the performance of an application often depends on the Java Virtual Machine's (JVM) ability to handle synchronization quickly and efficiently when it occurs. The IBM JVM has long incorporated optimizations to make synchronization fast and efficient. Refinements made to these optimizations, which are present in the JVM shipped with IBM WebSphere Application Server V8, include techniques that reduce both the memory and CPU requirements for the JVM's support of efficient synchronization, which in turn can lead to improved application performance