Small things matter: sometimes the smallest detail can have an impact far beyond your imagination.
In this talk, we'll discuss a severe JVM performance issue discovered while working on Quarkus performance, but affecting the whole Java ecosystem. It is caused by a scalability bottleneck in OpenJDK existing for decades and is related to how CPUs are designed; the most surprising aspect is how common idioms will trigger the issue.
After explaining the issue Franz and Sanne will show how they improved performance by significant margins of several popular Java frameworks with simple, small changes.