JVM调优命令-jinfo

jinfo

JVM Configuration info这个命令作用是实时查看和调整虚拟机运行参数。 之前的jps -v口令只能查看到显示指定的参数，如果想要查看未被显示指定的参数的值就要使用jinfo口令。【JVM配置参数调整查看】

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[root@localhost bin]# 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

参数

-flag：输出指定args参数的值

-flags：输出所有JVM参数的值

-sysprops：输出系统属性，等同于System.getProperties()

示例

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[root@localhost bin]# jinfo -sysprops 24971 | more Attaching to process ID 24971, please wait... Debugger attached successfully. Server compiler detected. JVM version is 24.79-b02 java.runtime.name = Java(TM) SE Runtime Environment java.vm.version = 24.79-b02 sun.boot.library.path = /usr/local/java/jdk1.7.0_79/jre/lib/amd64 shared.loader = 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 java.util.logging.config.file = /home/yuhuo-tomcat/tomcat2/conf/logging.properties tomcat.util.buf.StringCache.byte.enabled = true sun.os.patch.level = unknown sun.java.launcher = SUN_STANDARD user.country = CN user.dir = /home/yuhuo-tomcat/tomcat2/bin java.vm.specification.name = Java Virtual Machine Specification java.runtime.version = 1.7.0_79-b15 org.apache.catalina.startup.TldConfig.jarsToSkip = tomcat7-websocket.jar java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment os.arch = amd64

1 2	[root@localhost bin]# jinfo -flag MaxPermSize 24971 -XX:MaxPermSize=85983232