UUID经常用来作为唯一键得生成算法被普遍使用，然而，高并发下，UUID的性能会下降非常快。这是依赖于UUID的种子输入以及算法，下面程序可以验证UUID的性能
import com.github.f4b6a3.uuid.UuidCreator;
import org.openjdk.jmh.annotations.*;
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;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 2)
@Measurement(iterations = 2, time = 5, timeUnit = TimeUnit.SECONDS)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
@Threads(100)
@Fork(1)
public class UUIDTest {
@Benchmark
public UUID uuidDefault(){
return UUID.randomUUID();
}
@Benchmark
@Fork(value=1,jvmArgsAppend="-Djava.security.egd=file:/dev/urandom")
public UUID uuidNonblockRandom(){
return UUID.randomUUID();
}
@Benchmark
@Fork(value=1,jvmArgsAppend="-Djava.security.egd=file:/dev/random")
public UUID uuidBlockRandom(){
return UUID.randomUUID();
}
@Benchmark
@Fork(value=1,jvmArgsAppend="-Djava.security.egd=file:/dev/./urandom")
public UUID uuidNonblockRandom_2(){
return UUID.randomUUID();
}
@Benchmark
@Fork(value=1)
public UUID timeBasedUUID(){
return UuidCreator.getTimeBased();
}
public static void main(String[] args) throws RunnerException {
Options opt = new OptionsBuilder()
.include(UUIDTest.class.getSimpleName())
.forks(1)
.syncIterations(false)
.build();
new Runner(opt).run();
}
}
maven 文件
<properties>
<jmh.version>1.35</jmh.version>
</properties>
<dependencies>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-core</artifactId>
<version>${jmh.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>${jmh.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.github.f4b6a3</groupId>
<artifactId>uuid-creator</artifactId>
<version>4.6.1</version>
</dependency>
</dependencies>
在一个8C服务器上，200并发测试
Benchmark Mode Cnt Score Error Units
TestPerUUID.timeBasedUUID avgt 2 12121.222 ns/op
TestPerUUID.uuidBlockRandom avgt 2 171027.253 ns/op
TestPerUUID.uuidDefault avgt 2 186085.858 ns/op
TestPerUUID.uuidNonblockRandom avgt 2 238918.598 ns/op
TestPerUUID.uuidNonblockRandom_2 avgt 2 60984.722 ns/op
