ejb remote client hangs on undertow default worker pool exhaustion

>Steps to reproduce get 2 jboss instances: destination and client setup ejb-remoting according to article "https://docs.jboss.org/author/display/WFLY10/EJB+invocations+from+a+remote+server+instance" install to destination .ear with remotely accessible slsb, doing Thread.sleep(1000) install to client .war with servlet calling method make lot (>300) of concurrent get request to servlet using some bench tool (e.g. https://github.com/wg/wrk ) >Actual results Servlet hang, all threads waiting for responses like this: "default task-40" #331 prio=5 os_prio=0 tid=0x00007f2d7c256800 nid=0x1bf6 in Object.wait() [0x00007f2ca2db2000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Object.wait(Object.java:502) at org.jboss.ejb.client.EJBClientInvocationContext.awaitResponse(EJBClientInvocationContext.java:413) locked <0x00000000d6253958> (a java.lang.Object) at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:204) at org.jboss.ejb.client.EJBInvocationHandler.doInvoke(EJBInvocationHandler.java:183) at org.jboss.ejb.client.EJBInvocationHandler.invoke(EJBInvocationHandler.java:146) at com.sun.proxy.$Proxy253.process(Unknown Source) > Expected result: No hang > Additional info AFAICU ejb-client need spare thread in default xnio worker to process responses. all threads occupied by processing of servlet requests. No thread to make following EJBClientInvocationContext.resultReady(EJBReceiverInvocationContext$ResultProducer) line: 313 EJBReceiverInvocationContext.resultReady(EJBReceiverInvocationContext$ResultProducer) line: 73 ChannelAssociation.resultReady(short, EJBReceiverInvocationContext$ResultProducer) line: 241 MethodInvocationResponseHandler.processMessage(InputStream) line: 82 ChannelAssociation.processResponse(InputStream) line: 395 ChannelAssociation$ResponseReceiver.handleMessage(Channel, MessageInputStream) line: 507 RemoteConnectionChannel$5.run() line: 456 EndpointImpl$TrackingExecutor$1.run() line: 731 XnioWorker$TaskPool(ThreadPoolExecutor).runWorker(ThreadPoolExecutor$Worker) line: 1142 ThreadPoolExecutor$Worker.run() line: 617 Thread.run() line: 745