The evolution of a high-performing Java virtual machine

Early Java(TM) virtual machines (Jvms) possessed several significant perfor mance bottlenecks that inhibited the speed of Java workloads. This paper pr esents the methodology that was used by ISM to identify and eliminate these bottlenecks for improving the performance of Java applications running on several operating system platforms. In addition, several of the key perform ance problems that were common to all early Java virtual machine implementa tions and how they were solved for ISM enhanced Jvms are described in detai l. The issues discussed in this paper are focused on problems found in core Jvm components, such as object synchronization, object allocation, heap ma nagement, text rendering; run-time resolution, and Java class library metho ds. The results obtained from applying the described methodology and elimin ating the identified performance bottlenecks increased the performance of I SM Java virtual machines by as much as four times on some workloads. The te chnology discussed in this paper is applicable to other Jvm implementations .