Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1420222

Customer has reported a very poor performance with JBoss and JDK 8. When they turned the -XX:+TieredCompilation flag off they saw a dramatic improvement in JBoss server performance.

In this particular case it was the JCA subsystem that was most affected with getConnection() times varying from 1ms to 540ms. All other factors (like GC for example) have been eliminated). Once the flag has been turned off the getConnection() was performing consistently within the requirements.

They argue we should turn this flag off by default. The JDK 8 turns it on by default.