Did you also get a message showing which Threads are involved here (the 'Locked By' etc) ?
If so: check the Stack Trace for the 'Locked by' (and 'Originally Locked by' - if different); the long running thread and triggered the Thread Dump will just show the thread-dump being requested; you want to see what was holding up the thread in the first place.
Thread dump was generated due to the long running requester (more threads are waiting for one long running requester). This was identified on the performance testing. where can I find the configurations for threshold for the long running requester and thread dump generation threshold ?