Book Image

Oracle JRockit: The Definitive Guide

Book Image

Oracle JRockit: The Definitive Guide

Overview of this book

Oracle JRockit is one of the industry’s highest performing Java Virtual Machines. Java developers are always on the lookout for better ways to analyze application behavior and gain performance. As we all know, this is not as easy as it looks. Welcome to JRockit: The Definitive Guide.This book helps you gain in-depth knowledge of Java from the JVM’s point of view. We will explain how to write code that works well with the JVM to gain performance and scalability. Starting with the inner workings of the JRockit JVM and finishing with a thorough walkthrough of the tools in the JRockit Mission Control suite, this book is for anyone who wants to know more about how the JVM executes your Java application and how to profile for better performance.
Table of Contents (23 chapters)
Oracle JRockit
Credits
Foreword
About the Authors
Acknowledgement
About the Reviewers
Preface
12
Using the JRockit Management APIs
Bibliography
Glossary
AST
CAS
HIR
IR
JFR
JMX
JRA
JSR
LIR
MD5
MIR
PDE
RCP
SWT
TLA
Index

Troubleshooting


Sometimes, there will be no data in the Code | Hot methods tab, even if the method sampling was enabled. The most common reason is that the application did not generate enough load to provide the method sampler with data. The method sampler only samples threads that are actively running Java code. If the recording is short and the threads are spending most of their time waiting and doing nothing, chances are that no samples will be recorded at all. If you aren't profiling a production system, try to stress your application during profiling, if possible in a manner that is close to the real deployment scenario.

When using native method sampling, all samples will be stored. Normally, only the samples for threads executing Java will be stored. Don't be surprised if you find almost all of the native samples to be in some native method, such as ntdll.dll#KiFastSystemCallRet, even when the system is mostly idle.