java benchmark 基准测试的实例详解
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import java.util.arrays;
import java.util.concurrent.timeunit;
import org.openjdk.jmh.annotations.benchmark;
import org.openjdk.jmh.annotations.benchmarkmode;
import org.openjdk.jmh.annotations.measurement;
import org.openjdk.jmh.annotations.mode;
import org.openjdk.jmh.annotations.outputtimeunit;
import org.openjdk.jmh.annotations.scope;
import org.openjdk.jmh.annotations.state;
import org.openjdk.jmh.annotations.threads;
import org.openjdk.jmh.annotations.warmup;
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;
@benchmarkmode(mode.throughput)//基准测试类型
@outputtimeunit(timeunit.seconds)//基准测试结果的时间类型
@warmup(iterations = 3)//预热的迭代次数
@threads(2)//测试线程数量
@state(scope.thread)//该状态为每个线程独享
//度量:iterations进行测试的轮次，time每轮进行的时长，timeunit时长单位,batchsize批次数量
@measurement(iterations = 2, time = -1, timeunit = timeunit.seconds, batchsize = -1)
public class instructionsbenchmark{
static int staticpos = 0;
//string src = "select a from ab , ee.ff as f,(select a from `schema_bb`.`tbl_bb`,(select a from ccc as c, `dddd`));";
final byte[] srcbytes = {83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 97, 98, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 44, 32, 101, 101, 46, 102, 102, 32, 65, 83, 32, 102, 44, 40, 83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 96, 115, 99, 104, 101, 109, 97, 95, 98, 98, 96, 46, 96, 116, 98, 108, 95, 98, 98, 96, 44, 40, 83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 99, 99, 99, 32, 65, 83, 32, 99, 44, 32, 96, 100, 100, 100, 100, 96, 41, 41, 59};
int len = srcbytes.length;
byte[] array = new byte[8192];
int membervariable = 0;
//run
public static void main(string[] args) throws runnerexception {
options opt = new optionsbuilder()
.include(instructionsbenchmark.class.getsimplename())
.forks(1)
// 使用之前要安装hsdis
//-xx:-tieredcompilation 关闭分层优化 -server
//-xx:+logcompilation 运行之后项目路径会出现按照测试顺序输出hotspot_pid<pid>.log文件,可以使用jitwatch进行分析,可以根据最后运行的结果的顺序按文件时间找到对应的hotspot_pid<pid>.log文件
.jvmargs("-xx:+unlockdiagnosticvmoptions", "-xx:+logcompilation", "-xx:+traceclassloading", "-xx:+printassembly")
// .addprofiler(compilerprofiler.class) // report jit compiler profiling via standard mbeans
// .addprofiler(gcprofiler.class) // report gc time
// .addprofiler(stackprofiler.class) // report method stack execution profile
// .addprofiler(pausesprofiler.class)
/*
winperfasmprofiler
you must install windows performance toolkit. once installed, locate directory with xperf.exe file
and either add it to path environment variable, or set it to jmh.perfasm.xperf.dir system property.
*/
//.addprofiler(winperfasmprofiler.class)
//更多profiler,请看jmh介绍
//.output("instructionsbenchmark.log")//输出信息到文件
.build();
new runner(opt).run();
}
//空循环 对照项
@benchmark
public int emptyloop() {
int pos = 0;
while (pos < len) {
++pos;
}
return pos;
}
@benchmark
public int increment() {
int pos = 0;
int result = 0;
while (pos < len) {
++result;
++pos;
}
return result;
}
@benchmark
public int decrement() {
int pos = 0;
int result = 0;
while (pos < len) {
--result;
++pos;
}
return result;
}
@benchmark
public int ifelse() {
int pos = 0;
int result = 0;
while (pos < len) {
if (pos == 10) {
++result;
++pos;
} else {
++pos;
}
}
return result;
}
@benchmark
public int ifelse2() {
int pos = 0;
int result = 0;
while (pos < len) {
if (pos == 10) {
++result;
++pos;
} else if (pos == 20) {
++result;
++pos;
} else {
++pos;
}
}
return result;
}
@benchmark
public int ifnotelse() {
int pos = 0;
int result = 0;
while (pos < len) {
if (pos != 10) {
++pos;
} else {
++result;
++pos;
}
}
return result;
}
@benchmark
public int iflessthanelse() {
int pos = 0;
int result = 0;
while (pos < len) {
if (pos < 10) {
++pos;
} else {
++result;
++pos;
}
}
return result;
}
@benchmark
public int ifgreaterthanelse() {
int pos = 0;
int result = 0;
while (pos < len) {
if (pos > 10) {
++pos;
} else {
++result;
++pos;
}
}
return result;
}
@benchmark
public int readmembervariable_a_bytearray() {
int pos = 0;
int result = 0;
while (pos < len) {
result = srcbytes[pos];
pos++;
}
return result;
}
}
ops/time：标识每秒钟执行的次数
依赖jar包：
<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>
<build>
<plugins>
<plugin>
<groupid>org.codehaus.mojo</groupid>
<artifactid>exec-maven-plugin</artifactid>
<executions>
<execution>
<id>run-benchmarks</id>
<phase>integration-test</phase>
<goals>
<goal>exec</goal>
</goals>
<configuration>
<classpathscope>test</classpathscope>
<executable>java</executable>
<arguments>
<argument>-classpath</argument>
<classpath />
<argument>org.openjdk.jmh.main</argument>
<argument>.*</argument>
</arguments>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
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