JVM Tutorials - Herong's Tutorial Examples

∟Micro Benchmark Runner and JVM Options

This chapter provides tutorial notes and example codes on micro benchmark testing. Topics include micro benchmark guidelines; controlling and watching JIT compilation; controlling and watching GC.

What Is Micro Benchmark?

BenchmarkRunner.java - Benchmark Runner Program

emptyLoop() - The Empty Loop Test Method

"-XX:+PrintCompilation" - Watching JIT Compilation Logs

"-XX:+PrintGC" - Watching GC (Garbage Collection) Logs

"-Xms" and "-Xmx" - Avoiding GC with Large Memory Size

Benchmark Affected by Other Running Applications

"-Xint" - Running in Interpreted-Only Mode

Conclusions:

• Micro benchmark is a benchmark designed to measure the performance of a very small and specific piece of code.
• A benchmark program can be designed in 2 parts: a benchmark runner and a test method.
• "-XX:+PrintCompilation" option allows you to watch the JIT compilation log.
• "-XX:+PrintGC" option allows you to watch the GC log.
• "-Xms" and "-Xmx" options allow you to allocate a large memory to avoid GC.
• "-Xint" option allows you to run test in interpreted-only mode - disabling the JIT compiler.

Table of Contents

 About This Book

 Download and Install Java SE 1.6 Update 2

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 Sun's JVM - Java HotSpot VM

 JRockit JVM 7.0 by BEA Systems

 JRockit JVM 8.0 by BEA Systems

 Memory Management Rules and Tests

 Garbage Collection Tests

 Stack Overflow Tests

 Thread Testing Program and Result

 StringBuffer Testing Program and Result

 CDS (Class Data Sharing)

►Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

 Micro Benchmark Tests on "long" Operations

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

 References

 PDF Printing Version