JPerf 2.0.0

This is a complete re-write of JPerf, using java.util.concurrency and removing any use of synchronized or volatile keywords. JPerf now has significantly less overhead compared to earlier releases.

The API has also been improved, using a builder pattern, and allowing for lambda functions to supply test factories.

JPerf 1.3.1

JPerf 1.3 greatly improves the scalability of JPerf itself by reducing the frequency of writes to shared memory between the threads. For the simple NoOpTest example, throughput with 10 threads has increased close to 20x on my 2012 iMac.

JPerf 1.3.1 contains minor changes to the README and adds a "clean" target to the ant build script.