Showing posts from May, 2016

Benchmarking Java Locks with Counters

These days I am analyzing some Java Flight Recordings from taken from WSO2 API Manager performance tests and I found out that main processing threads were in "BLOCKED" state in some situations.

The threads were mainly blocked due to "synchronized" methods in Java. Synchronizing the methods in a critical section of request processing causes bottlenecks and it has an impact on the throughput and overall latency.

Then I was thinking whether we could avoid synchronizing the whole method. The main problem with synchronized is that only one thread can run that critical section. When it comes to consumer/producer scenarios, we may need to give read access to data in some threads and write access to a thread to edit data exclusively. Java provides ReadWriteLock for these kinds of scenarios.

Java 8 provides another kind of lock named StampedLock. The StampedLock provides an alternative way to the standard ReadWriteLock and it also supports optimistic reads. I'm not goi…