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# perfcounter
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Check the current JVM Perf Counter information.
# Usage
$ perfcounter
java.ci.totalTime 2325637411
java.cls.loadedClasses 3403
java.cls.sharedLoadedClasses 0
java.cls.sharedUnloadedClasses 0
java.cls.unloadedClasses 0
java.property.java.version 11.0.4
java.property.java.vm.info mixed mode
java.property.java.vm.name OpenJDK 64-Bit Server VM
...
Print more information with the -d option:
$ perfcounter -d
Name Variability Units Value
---------------------------------------------------------------------------------
java.ci.totalTime Monotonic Ticks 3242526906
java.cls.loadedClasses Monotonic Events 3404
java.cls.sharedLoadedClasses Monotonic Events 0
java.cls.sharedUnloadedClasses Monotonic Events 0
java.cls.unloadedClasses Monotonic Events 0
# JVM above JDK9
If the information is not printed, when the application starts, add the following parameters:
--add-opens java.base/jdk.internal.perf=ALL-UNNAMED --add-exports java.base/jdk.internal.perf=ALL-UNNAMED --add-opens java.management/sun.management.counter.perf=ALL-UNNAMED --add-opens java.management/sun.management.counter=ALL-UNNAMED