Tuning the Oracle JRockit JVM to achieve optimal application performance is about the most critical aspect using this product. A poorly-tuned JVM can result in slow transactions, long latencies, system freezes, and even system crashes. This documen explores the many tuning techniques and options you can employ to see that your implementation of this JVM performs to maximum capabilities.
How to Tune: An Overview
Ideally, tuning should occur as part of the system startup, by employing various combinations of the start-up options described in the Oracle JRockit JVM
Command-Line Reference. The Oracle JRockit JDK provides the necessary tools for monitoring your application during runtime. Properly tuned, according to the recommendations in this section, the JVM should run smoothly and provide timely results. Should runtime monitoring indicate problems along the way, you can use the recommendations in this section to guide you toward a better-tuned JVM.
What this Section Contains
This section includes information on the following subjects:
While tuning the JRockit JVM you will often find a certain trade-off between short garbage collection pause times, high application throughput and low memory footprint. Understanding the Tuning Trade-offs describes these trade-offs and the reasons behind them.
Each Java application has its own behavior and its own requirements. The JRockit JVM can accommodate most of them automatically, but to get the optimal performance you should tune at least some basic parameters. First Steps for Tuning the Oracle JRockit JVM gives an overview of the first steps of tuning the JRockit JVM and some best practices for tuning the JVM for a few different Oracle applications.
A correctly tuned memory management system minimizes the overhead inflicted by garbage collection and makes object allocation fast. Tuning the Memory Management System covers the most important options available for tuning the memory management system in the JRockit JVM.
The interaction between Java threads affects the performance of your application. Tuning Locks contains information about the JRockit JVM options for tuning how locks and contention for locks are handled.
Do you want your application to run smoothly with minimal pauses caused by the garbage collection? If the answer is “yes”, then you want to tune for short pause times. Using the tuning techniques described in Tuning For Low Latencies to ensure that pause times are kept to a minimum and transactions execute quickly.
Do you want to minimize the total amount of CPU time spent in garbage collection and spend more time in the application layer? If the answer is “yes”, then you want to tune for high application performance, or application throughput. Tuning For Better Application Throughput describes how to tune your Oracle JRockit JVM to ensure that the Java application runs as fast as possible with minimal garbage collector overhead.
