Performance problems with jBPM process creation under high load in BRMS 5.3

Issue

We are testing an application based on jBPM 5.2, and we are experiencing that response time is too long for our business requirements. Analysing the logs, we observed that the creation of a new session is really time expensive (about 6 seconds, in some cases).

From the captured threads-dump we found that many threads are in "waiting on monitor" state, on the "jbpm.task.service.TaskService.initialize" call from within our class.

    protected LocalTaskService createTaskService(EntityManagerFactory emf) {
        TaskService taskService = new TaskService(emf, SystemEventListenerFactory.getSystemEventListener());
        return new LocalTaskService(taskService);
    }