jdk8:jinfo命令

原創 行者路上 2018-08-22 06:33

jinfo 用法

➜  ~ jinfo --help
Usage:
    jinfo [option] <pid>
        (to connect to running process)
    jinfo [option] <executable <core>
        (to connect to a core file)
    jinfo [option] [server_id@]<remote server IP or hostname>
        (to connect to remote debug server)

where <option> is one of:
    -flag <name>         to print the value of the named VM flag
    -flag [+|-]<name>    to enable or disable the named VM flag
    -flag <name>=<value> to set the named VM flag to the given value
    -flags               to print VM flags
    -sysprops            to print Java system properties
    <no option>          to print both of the above
    -h | -help           to print this help message

查看正在運行的Java應用程序的擴展參數

jinfo -flags process_id

➜ ~ jinfo -flags 31983
Attaching to process ID 31983, please wait…
Debugger attached successfully.
Server compiler detected.
JVM version is 25.91-b14
Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=20971520 -XX:MaxHeapFreeRatio=90 -XX:MaxHeapSize=20971520 -XX:MaxNewSize=2097152 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=2097152 -XX:OldSize=18874368 -XX:+PrintGC -XX:+PrintGCDetails -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:+UseParallelGC
Command line: -Xmx20m -Xms20m -Xmn2m -javaagent:/opt/idea-IU-181.4668.68/lib/idea_rt.jar=34989:/opt/idea-IU-181.4668.68/bin -Dfile.encoding=UTF-8

jinfo process_id

➜  ~ jinfo  31983      
Attaching to process ID 31983, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.91-b14
Java System Properties:

java.runtime.name = Java(TM) SE Runtime Environment
java.vm.version = 25.91-b14
sun.boot.library.path = /opt/jdk1.8.0_91/jre/lib/amd64
java.vendor.url = http://java.oracle.com/
java.vm.vendor = Oracle Corporation
path.separator = :
file.encoding.pkg = sun.io
java.vm.name = Java HotSpot(TM) 64-Bit Server VM
sun.os.patch.level = unknown
sun.java.launcher = SUN_STANDARD
user.country = CN
user.dir = /home/wangzhenya/IdeaProjects/core_java
java.vm.specification.name = Java Virtual Machine Specification
java.runtime.version = 1.8.0_91-b14
java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment
os.arch = amd64
java.endorsed.dirs = /opt/jdk1.8.0_91/jre/lib/endorsed
java.io.tmpdir = /tmp
line.separator = 

java.vm.specification.vendor = Oracle Corporation
os.name = Linux
sun.jnu.encoding = UTF-8
java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.specification.name = Java Platform API Specification
java.class.version = 52.0
sun.management.compiler = HotSpot 64-Bit Tiered Compilers
os.version = 4.15.0-24-generic
user.home = /home/wangzhenya
user.timezone = 
java.awt.printerjob = sun.print.PSPrinterJob
file.encoding = UTF-8
java.specification.version = 1.8
user.name = wangzhenya
java.class.path = /opt/jdk1.8.0_91/jre/lib/charsets.jar:/opt/jdk1.8.0_91/jre/lib/deploy.jar:/opt/jdk1.8.0_91/jre/lib/ext/cldrdata.jar:/opt/jdk1.8.0_91/jre/lib/ext/dnsns.jar:/opt/jdk1.8.0_91/jre/lib/ext/jaccess.jar:/opt/jdk1.8.0_91/jre/lib/ext/jfxrt.jar:/opt/jdk1.8.0_91/jre/lib/ext/localedata.jar:/opt/jdk1.8.0_91/jre/lib/ext/nashorn.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunec.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunjce_provider.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunpkcs11.jar:/opt/jdk1.8.0_91/jre/lib/ext/zipfs.jar:/opt/jdk1.8.0_91/jre/lib/javaws.jar:/opt/jdk1.8.0_91/jre/lib/jce.jar:/opt/jdk1.8.0_91/jre/lib/jfr.jar:/opt/jdk1.8.0_91/jre/lib/jfxswt.jar:/opt/jdk1.8.0_91/jre/lib/jsse.jar:/opt/jdk1.8.0_91/jre/lib/management-agent.jar:/opt/jdk1.8.0_91/jre/lib/plugin.jar:/opt/jdk1.8.0_91/jre/lib/resources.jar:/opt/jdk1.8.0_91/jre/lib/rt.jar:/home/wangzhenya/IdeaProjects/core_java/target/classes:/home/wangzhenya/.m2/repository/io/netty/netty-all/4.1.7.Final/netty-all-4.1.7.Final.jar:/home/wangzhenya/.m2/repository/junit/junit/4.12/junit-4.12.jar:/home/wangzhenya/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar:/home/wangzhenya/.m2/repository/com/lmax/disruptor/3.3.0/disruptor-3.3.0.jar:/home/wangzhenya/.m2/repository/com/rabbitmq/amqp-client/5.3.0/amqp-client-5.3.0.jar:/home/wangzhenya/.m2/repository/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar:/opt/idea-IU-181.4668.68/lib/idea_rt.jar
java.vm.specification.version = 1.8
sun.arch.data.model = 64
sun.java.command = com.own.learn.jvm.JinfoTest
java.home = /opt/jdk1.8.0_91/jre
user.language = zh
java.specification.vendor = Oracle Corporation
awt.toolkit = sun.awt.X11.XToolkit
java.vm.info = mixed mode
java.version = 1.8.0_91
java.ext.dirs = /opt/jdk1.8.0_91/jre/lib/ext:/usr/java/packages/lib/ext
sun.boot.class.path = /opt/jdk1.8.0_91/jre/lib/resources.jar:/opt/jdk1.8.0_91/jre/lib/rt.jar:/opt/jdk1.8.0_91/jre/lib/sunrsasign.jar:/opt/jdk1.8.0_91/jre/lib/jsse.jar:/opt/jdk1.8.0_91/jre/lib/jce.jar:/opt/jdk1.8.0_91/jre/lib/charsets.jar:/opt/jdk1.8.0_91/jre/lib/jfr.jar:/opt/jdk1.8.0_91/jre/classes
java.vendor = Oracle Corporation
file.separator = /
java.vendor.url.bug = http://bugreport.sun.com/bugreport/
sun.io.unicode.encoding = UnicodeLittle
sun.cpu.endian = little
sun.desktop = gnome
sun.cpu.isalist = 

VM Flags:
Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=20971520 -XX:MaxHeapFreeRatio=90 -XX:MaxHeapSize=20971520 -XX:MaxNewSize=2097152 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=2097152 -XX:OldSize=18874368 -XX:+PrintGC -XX:+PrintGCDetails -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseFastUnorderedTimeStamps -XX:+UseParallelGC 
Command line:  -Xmx20m -Xms20m -Xmn2m -javaagent:/opt/idea-IU-181.4668.68/lib/idea_rt.jar=34989:/opt/idea-IU-181.4668.68/bin -Dfile.encoding=UTF-8

jinfo -sysprops process_id等於 System.getProperties()

➜ ~ jinfo -sysprops 31983
Attaching to process ID 31983, please wait…
Debugger attached successfully.
Server compiler detected.
JVM version is 25.91-b14
java.runtime.name = Java(TM) SE Runtime Environment
java.vm.version = 25.91-b14
sun.boot.library.path = /opt/jdk1.8.0_91/jre/lib/amd64
java.vendor.url = http://java.oracle.com/
java.vm.vendor = Oracle Corporation
path.separator = :
file.encoding.pkg = sun.io
java.vm.name = Java HotSpot(TM) 64-Bit Server VM
sun.os.patch.level = unknown
sun.java.launcher = SUN_STANDARD
user.country = CN
user.dir = /home/wangzhenya/IdeaProjects/core_java
java.vm.specification.name = Java Virtual Machine Specification
java.runtime.version = 1.8.0_91-b14
java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment
os.arch = amd64
java.endorsed.dirs = /opt/jdk1.8.0_91/jre/lib/endorsed
java.io.tmpdir = /tmp
line.separator =

java.vm.specification.vendor = Oracle Corporation
os.name = Linux
sun.jnu.encoding = UTF-8
java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.specification.name = Java Platform API Specification
java.class.version = 52.0
sun.management.compiler = HotSpot 64-Bit Tiered Compilers
os.version = 4.15.0-24-generic
user.home = /home/wangzhenya
user.timezone =
java.awt.printerjob = sun.print.PSPrinterJob
file.encoding = UTF-8
java.specification.version = 1.8
user.name = wangzhenya
java.class.path = /opt/jdk1.8.0_91/jre/lib/charsets.jar:/opt/jdk1.8.0_91/jre/lib/deploy.jar:/opt/jdk1.8.0_91/jre/lib/ext/cldrdata.jar:/opt/jdk1.8.0_91/jre/lib/ext/dnsns.jar:/opt/jdk1.8.0_91/jre/lib/ext/jaccess.jar:/opt/jdk1.8.0_91/jre/lib/ext/jfxrt.jar:/opt/jdk1.8.0_91/jre/lib/ext/localedata.jar:/opt/jdk1.8.0_91/jre/lib/ext/nashorn.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunec.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunjce_provider.jar:/opt/jdk1.8.0_91/jre/lib/ext/sunpkcs11.jar:/opt/jdk1.8.0_91/jre/lib/ext/zipfs.jar:/opt/jdk1.8.0_91/jre/lib/javaws.jar:/opt/jdk1.8.0_91/jre/lib/jce.jar:/opt/jdk1.8.0_91/jre/lib/jfr.jar:/opt/jdk1.8.0_91/jre/lib/jfxswt.jar:/opt/jdk1.8.0_91/jre/lib/jsse.jar:/opt/jdk1.8.0_91/jre/lib/management-agent.jar:/opt/jdk1.8.0_91/jre/lib/plugin.jar:/opt/jdk1.8.0_91/jre/lib/resources.jar:/opt/jdk1.8.0_91/jre/lib/rt.jar:/home/wangzhenya/IdeaProjects/core_java/target/classes:/home/wangzhenya/.m2/repository/io/netty/netty-all/4.1.7.Final/netty-all-4.1.7.Final.jar:/home/wangzhenya/.m2/repository/junit/junit/4.12/junit-4.12.jar:/home/wangzhenya/.m2/repository/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar:/home/wangzhenya/.m2/repository/com/lmax/disruptor/3.3.0/disruptor-3.3.0.jar:/home/wangzhenya/.m2/repository/com/rabbitmq/amqp-client/5.3.0/amqp-client-5.3.0.jar:/home/wangzhenya/.m2/repository/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar:/opt/idea-IU-181.4668.68/lib/idea_rt.jar
java.vm.specification.version = 1.8
sun.arch.data.model = 64
sun.java.command = com.own.learn.jvm.JinfoTest
java.home = /opt/jdk1.8.0_91/jre
user.language = zh
java.specification.vendor = Oracle Corporation
awt.toolkit = sun.awt.X11.XToolkit
java.vm.info = mixed mode
java.version = 1.8.0_91
java.ext.dirs = /opt/jdk1.8.0_91/jre/lib/ext:/usr/java/packages/lib/ext
sun.boot.class.path = /opt/jdk1.8.0_91/jre/lib/resources.jar:/opt/jdk1.8.0_91/jre/lib/rt.jar:/opt/jdk1.8.0_91/jre/lib/sunrsasign.jar:/opt/jdk1.8.0_91/jre/lib/jsse.jar:/opt/jdk1.8.0_91/jre/lib/jce.jar:/opt/jdk1.8.0_91/jre/lib/charsets.jar:/opt/jdk1.8.0_91/jre/lib/jfr.jar:/opt/jdk1.8.0_91/jre/classes
java.vendor = Oracle Corporation
file.separator = /
java.vendor.url.bug = http://bugreport.sun.com/bugreport/
sun.io.unicode.encoding = UnicodeLittle
sun.cpu.endian = little
sun.desktop = gnome
sun.cpu.isalist =

jinfo -flag PID

➜  ~ jinfo -flag MaxMetaspaceSize 17808
-XX:MaxMetaspaceSize=18446744073709547520

調整JVM參數

用法：
如果是布爾類型的JVM參數: jinfo -flag [+|-] PID，enable or disable the named VM flag
如果是數字/字符串類型的JVM參數 jinfo -flag = PID，to set the named VM flag to the given value

哪些jvm的參數可以動態修改

Linux環境：java -XX:+PrintFlagsInitial | grep manageable
Window環境：java -XX:+PrintFlagsInitial | findstr manageable

➜ ~ java -XX:+PrintFlagsInitial | grep manageable
intx CMSAbortablePrecleanWaitMillis = 100 {manageable}
intx CMSTriggerInterval = -1 {manageable}
intx CMSWaitDuration = 2000 {manageable}
bool HeapDumpAfterFullGC = false {manageable}
bool HeapDumpBeforeFullGC = false {manageable}
bool HeapDumpOnOutOfMemoryError = false {manageable}
ccstr HeapDumpPath = {manageable}
uintx MaxHeapFreeRatio = 70 {manageable}
uintx MinHeapFreeRatio = 40 {manageable}
bool PrintClassHistogram = false {manageable}
bool PrintClassHistogramAfterFullGC = false {manageable}
bool PrintClassHistogramBeforeFullGC = false {manageable}
bool PrintConcurrentLocks = false {manageable}
bool PrintGC = false {manageable}
bool PrintGCDateStamps = false {manageable}
bool PrintGCDetails = false {manageable}
bool PrintGCID = false {manageable}
bool PrintGCTimeStamps = false {manageable}

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