Severe performance degradation due to Thread.getStackTrace call in ConcurrencyManager

[dettmoney]

I have a simple REST/JPA application running on open liberty that performs jpa queries. A change to the org.eclipse.persistence.internal.helper.ConcurrencyManager class is causing a 75% throughput performance degradation for that particular application (~26k req/sec down to ~6k req/sec). This affects master/3.0/2.7/2.6_WAS and appears to be introduced via #1038. Looking at ConcurrencyManager.acquire(), the code as written gets a full stack trace and parses out the current class and method information to construct a String:

             StackTraceElement stackTraceElement = currentThread.getStackTrace()[1];
             putThreadAsWaitingToAcquireLockForReading(currentThread, stackTraceElement.getClassName() + "." + stackTraceElement.getMethodName() + "(...)");

The getStackTrace() method is called in four methods in this class: acquire, acquireReadLock, acquireWithWait, acquireDeferredLock. I changed the code in my local environment to create private static Strings that contain the class/method information for each method, and I was able to recover the lost throughput performance.