JBoss stalled scheduling work to the JCA WorkManager

Issue

• JBoss slowed and showed heavy thread contention trying to schedule work to the JCA WorkManager:

Thread 470: (state = BLOCKED)
 - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information may be imprecise)
 - java.util.concurrent.locks.LockSupport.park(java.lang.Object) @bci=14, line=186 (Compiled frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await() @bci=42, line=2043 (Compiled frame)
 - org.jboss.threads.QueueExecutor.executeBlocking(java.lang.Runnable) @bci=138, line=253 (Compiled frame)
 - org.jboss.as.threads.ManagedQueueExecutorService.executeBlocking(java.lang.Runnable) @bci=5, line=120 (Compiled frame)
 - org.jboss.jca.core.workmanager.WorkManagerImpl.scheduleWork(javax.resource.spi.work.Work, long, javax.resource.spi.work.ExecutionContext, javax.resource.spi.work.WorkListener) @bci=205, line=583 (Compiled frame)

• How to explicitly configure the long running and short running threads? Where to do it?

• We are using Jboss eap 6.2 and we are using ironjcamar workmanager to process the work .
  we found a hung thread issue during our testing . As we observed this issue only occurred in case we use more than 40 or 50 workmanager thread .
  We have taken a thread dump that gives some clue .
  snippet froom thread dump is as below and full thread dump file has been attached .

WorkManagement" prio=10 tid=0x00007f4a6c5d2000 nid=0x5bc1 waiting on condition [0x00007f4c3839c000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000007d9286b30> (a java.util.concurrent.CountDownLatch$Sync)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:994)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1303)
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:236)
    at org.jboss.jca.core.workmanager.WorkManagerImpl.startWork(WorkManagerImpl.java:479)
    at com.j2fe.work.JavaxWorkManagerWrapper.startWork(JavaxWorkManagerWrapper.java:26)
    at com.j2fe.clustering.WorkReplication.startThread(WorkReplication.java:499)