JVM性能调优工具03-jinfo-Java程序配置工具

[超级链接:JVM性能调优工具学习记录-序章]

本章主要学习Java程序配置工具jinfo。

1.用途

查看和设置Java程序的配置参数。

2.语法

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1Usage:

2    jinfo [option] <pid>

3        (to connect to running process)

4    jinfo [option] <executable <core>

5        (to connect to a core file)

6    jinfo [option] [server_id@]<remote server IP or hostname>

7        (to connect to remote debug server)

8

9where <option> is one of:

10    -flag <name>         to print the value of the named VM flag

11    -flag [+|-]<name>    to enable or disable the named VM flag

12    -flag <name>=<value> to set the named VM flag to the given value

13    -flags               to print VM flags

14    -sysprops            to print Java system properties

15    <no option>          to print both of the above

16    -h | -help           to print this help message

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• flags：显示JVM参数。

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1//显示JVM参数

2C:\Users\hanchao>jinfo -flags 7484

3Attaching to process ID 7484, please wait...

4Debugger attached successfully.

5Server compiler detected.

6JVM version is 25.131-b11

7Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=134217728 -XX:MaxHeapSize=2126512128 -XX:MaxNewSize=708837376 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=44564480 -XX:OldSize=89653248 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:-UseLargePagesIndividualAllocation -XX:+UseParallelGC

8Command line:  -javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2017.3.2\lib\idea_rt.jar=52204:C:\Program Files\JetBrains\IntelliJ IDEA 2017.3.2\bin -Dfile.encoding=UTF-8

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• sysprops：显示应用程序属性。

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1//显示系统属性

2C:\Users\hanchao>jinfo -sysprops 7484

3Attaching to process ID 7484, please wait...

4Debugger attached successfully.

5Server compiler detected.

6JVM version is 25.131-b11

7java.runtime.name = Java(TM) SE Runtime Environment

8java.vm.version = 25.131-b11

9sun.boot.library.path = C:\Program Files\Java\jdk1.8.0_131\jre\bin

10...

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• flag <name>：显示指定参数的值。

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1//显示最大年老代阈值

2C:\Users\hanchao>jinfo -flag MaxTenuringThreshold 7484

3-XX:MaxTenuringThreshold=15

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• flag <name>=<value>：设置指定的参数。

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1//将最大年老代阈值设置成14，但是失败了。

2C:\Users\hanchao>jinfo -flag MaxTenuringThreshold=14 7484

3Exception in thread "main" com.sun.tools.attach.AttachOperationFailedException: flag 'MaxTenuringThreshold' cannot be changed

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5        at sun.tools.attach.WindowsVirtualMachine.execute(WindowsVirtualMachine.java:117)

6        at sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:261)

7        at sun.tools.attach.HotSpotVirtualMachine.setFlag(HotSpotVirtualMachine.java:234)

8        at sun.tools.jinfo.JInfo.flag(JInfo.java:134)

9        at sun.tools.jinfo.JInfo.main(JInfo.java:81)

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• flag [+|-]<name>：开启/关闭指定的配置。

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1//年轻代使用串行收集器，但是失败了。

2C:\Users\hanchao>jinfo -flag +UseSerialGC 7484

3Exception in thread "main" com.sun.tools.attach.AttachOperationFailedException: flag 'UseSerialGC' cannot be changed

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5        at sun.tools.attach.WindowsVirtualMachine.execute(WindowsVirtualMachine.java:117)

6        at sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:261)

7        at sun.tools.attach.HotSpotVirtualMachine.setFlag(HotSpotVirtualMachine.java:234)

8        at sun.tools.jinfo.JInfo.flag(JInfo.java:140)

9        at sun.tools.jinfo.JInfo.main(JInfo.java:81)

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