Portable Tracing of Lock Contention in Java Applications

Concurrent programming has become necessary to benefit from current multi-core processors. The main challenge is safely accessing shared resources from multiple parallel threads, which is typically done with locks. Simple locking mechanisms are easier to implement correctly, but often suffer from high lock contention, which means that threads frequently have to wait until another thread releases a lock. During development, it is difficult to tell when a simple locking mechanism provides adequate performance and scalability, and when more sophisticated locking is worth the additional complexity. Therefore, a tool is needed that shows locking bottlenecks in an application and enables developers to make changes where they pay off.