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Earnstone Java Performance Counters


There doesn't seem to be a whole lot of open source options for Java performance counters. Since we found it frustrating and rolled our own we decided to share our work so others could just ditto it. The over-arching principal is Simplicity or more importantly KISS. We wanted something fast, simple, easy to use, and thread-safe (did we mention fast and simple). Easy access from JMX or the JMX-HTML adapter if required. we opted for a simple under-engineered design.

  • IncrementCounter - A performance counter that counts. You may use simple atomic operations to increment and decrement the count value.
  • PercentCounter - A performance counter that calculates percent. Great for hit cache performance counters.
  • LastAccessTimeCounter - A performance counter for displaying last access time. Great for counters like last access time or up time.
  • AvgCounter - A performance counter for averaging over a sample. This is usually a base class for other more detailed counters, but it could be used to average anything.
  • AvgTimeCounter - A performance counter for averaging over a time sample. Great for things like average time in a method call or average time to process items.
  • PerfAvgCallsPerSec - A performance counter for calls per second over a time sample. Makes calculating things like transactions per second or transactions per hour a breeze.
  • CallbackCounter - A performance counter which calls a supplied update method before returning the value. Great for integrating existing counters into a unified system.
  • Registry - A central repository for storing your performance counters. The registry is optional, but will be needed to access features like exposing counters through JMX or via the JMX-HTML adapter.


Building ePerf

Building ePerf can be a little tricky because of the jmxtools.jar dependency from Sun does not exist in a maven repository because of licensing issues. Below are steps needed to manually install this jar into your local repository.

if you look inside the jmxtools-1.2.1.pom it contains a link to the jmxtools.jar download site. You will need to scan through the page and find the hidden download link to the file Extract the contents and cd into the lib directory and run the following command:

mvn install:install-file -Dfile=jmxtools.jar -DgroupId=com.sun.jdmk -DartifactId=jmxtools -Dversion=1.2.1 -Dpackaging=jar

Your project should be good to go. Now you can perform local builds using the mvn commands.


Earnstone Java Performance Counters







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