Execute below command to create a maven jmh archetype
mvn archetype:generate \
-DinteractiveMode=false \
-DarchetypeGroupId=org.openjdk.jmh \
-DarchetypeArtifactId=jmh-java-benchmark-archetype \
-DgroupId=com.demo \
-DartifactId=JMHDemo \
-Dversion=1.0
You can import this project into eclipse. File > Import > Existing Maven Project
Lets create a JMH benchmark to compare looping of array list. Example below
package com.demo;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.infra.Blackhole;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
/*
http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@State(Scope.Benchmark)
@Fork(value = 2, jvmArgs = {"-Xms2G", "-Xmx2G"})
//@Warmup(iterations = 3)
//@Measurement(iterations = 8)
public class BenchmarkLoop {
@Param({"10000000"})
private int N;
private List<String> DATA_FOR_TESTING;
public static void main(String[] args) throws RunnerException {
Options opt = new OptionsBuilder()
.include(BenchmarkLoop.class.getSimpleName())
.forks(1)
.build();
new Runner(opt).run();
}
@Setup
public void setup() {
DATA_FOR_TESTING = createData();
}
@Benchmark
public void loopFor(Blackhole bh) {
for (int i = 0; i < DATA_FOR_TESTING.size(); i++) {
String s = DATA_FOR_TESTING.get(i); //take out n consume, fair with foreach
bh.consume(s);
}
}
@Benchmark
public void loopWhile(Blackhole bh) {
int i = 0;
while (i < DATA_FOR_TESTING.size()) {
String s = DATA_FOR_TESTING.get(i);
bh.consume(s);
i++;
}
}
@Benchmark
public void loopForEach(Blackhole bh) {
for (String s : DATA_FOR_TESTING) {
bh.consume(s);
}
}
@Benchmark
public void loopIterator(Blackhole bh) {
Iterator<String> iterator = DATA_FOR_TESTING.iterator();
while (iterator.hasNext()) {
String s = iterator.next();
bh.consume(s);
}
}
private List<String> createData() {
List<String> data = new ArrayList<>();
for (int i = 0; i < N; i++) {
data.add("Number : " + i);
}
return data;
}
}
- Eclipse Maven Clean
- Eclipse Maven Install
- Run as a Java Application