kie-server performance degrades over time

Under heavy load, the transaction per seconds value keeps decreasing.

We have found out, that on every KieServer invocation udpateReleaseId methos is called
see:
https://github.com/droolsjbpm/droolsjbpm-integration/blob/6.4.x/kie-server-parent/kie-server-services/kie-server-services-common/src/main/java/org/kie/server/services/impl/KieContainerInstanceImpl.java#L83

This leads to frequent invocations of getMarshallers and disposeMarshallers methods
https://github.com/droolsjbpm/droolsjbpm-integration/blob/master/kie-server-parent/kie-server-services/kie-server-services-common/src/main/java/org/kie/server/services/impl/KieContainerInstanceImpl.java#L120

However - these methods are synchronized. Which is creating bottle neck during concurrent access - imagine 20 threads starting a process deployed onto kie-server in a loop for 10 min.

We have found out that updateReleaseId() call was removed after this was fixed
https://issues.jboss.org/browse/JBPM-5235
It looks fine now:
https://github.com/droolsjbpm/droolsjbpm-integration/blob/6.5.x/kie-server-parent/kie-server-services/kie-server-services-common/src/main/java/org/kie/server/services/impl/KieContainerInstanceImpl.java#L86

With this fix in place - we are no longer observing performance degradation over time.

Find the attached gc logs and thread dumps