-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/24/2013 09:21 AM, shanliang wrote: > Just to be a test, after terminated 8 threads and checked their > states by calling Thread.join() (must be same to > Thread.getState()), DO sleep sometime and then call > mbean.getThreadCount(), if it reports a right number, then we may > need to verify mbean.getThreadCount() method.
The result is: Thread: Thread[Signal Dispatcher,9,system] Thread: Thread[Finalizer,8,system] Thread: Thread[worker-12,5,main] Thread: Thread[Reference Handler,10,system] Thread: Thread[main,5,main] Thread: Thread[worker-13,5,main] - ---> MBean.getThreadCount() = 7 Thread(1): Thread[Signal Dispatcher,9,system] Thread(1): Thread[Finalizer,8,system] Thread(1): Thread[worker-12,5,main] Thread(1): Thread[Reference Handler,10,system] Thread(1): Thread[main,5,main] Thread(1): Thread[worker-13,5,main] - ---> MBean.getThreadCount() = 6 - -JB- > > Shanliang > > Jaroslav Bachorik wrote: >> On Wed 24 Jul 2013 08:20:56 AM CEST, Mandy Chung wrote: >> >>> On 7/24/2013 2:09 PM, Daniel Fuchs wrote: >>> >>>> On 7/24/13 8:01 AM, Mandy Chung wrote: >>>> >>>>> I am catching up on this thread.... >>>>> >>>>> The thread count counts Java threads that are not hidden. >>>>> I believe all VM internal threads are hidden from external >>>>> API. This test runs in othervm mode and AFAICT the thread >>>>> count is expected to be deterministic. I don't expect the >>>>> VM will start and terminate any thread any time. >>>>> >>>>> I agree with David that we should diagnose why there is >>>>> one additional thread started before the reset. If it is >>>>> the LogManager$Cleaner thread, like David said, the VM is >>>>> shutting down while the test is still running which doesn't >>>>> quite make sense. >>>>> >>>> I think that Shanliang's suspicion that a thread might be >>>> still alive if unscheduled just after having called its >>>> barrier.signal() is a very good suggestion. I would advise >>>> calling thread.join() on all threads in terminateThreads, >>>> just to make sure they are all really dead and not in some >>>> comatose state... If Shanliang is right then the test would >>>> be failing because some of the threads we think are dead are >>>> not actually dead yet - and not because of some new VM thread >>>> that nobody can see :-) >>>> >>> Thanks for pointing that out. >>> >>> I agree that the test should be changed to call Thread.join(). >>> There may be other java.lang.management tests that should also >>> be fixed to call Thread.join. >>> >> >> I've tried using Thread.join() but I am still getting the thread >> count discrepancy. >> >> Specifically: 1. 10 worker threads have been successfully started >> - mben.getThreadCount() reports 14 and >> Thread.getAllStackTraces() returns 14 items --- Thread: >> Thread[Signal Dispatcher,9,system] Thread: >> Thread[worker-5,5,main] Thread: Thread[worker-7,5,main] Thread: >> Thread[worker-9,5,main] Thread: Thread[worker-12,5,main] Thread: >> Thread[worker-11,5,main] Thread: Thread[Reference >> Handler,10,system] Thread: Thread[main,5,main] Thread: >> Thread[worker-10,5,main] Thread: Thread[worker-8,5,main] Thread: >> Thread[Finalizer,8,system] Thread: Thread[worker-6,5,main] >> Thread: Thread[worker-13,5,main] Thread: Thread[worker-4,5,main] >> --- 2. Terminating 8 threads 3. After the threads have been >> terminated (waiting on Thread.join() for them to die) - >> mbean.getThreadCount() reports 7 while Thread.getAllStackTraces() >> returns only 6 items --- Thread: Thread[Signal >> Dispatcher,9,system] Thread: Thread[Finalizer,8,system] Thread: >> Thread[worker-12,5,main] Thread: Thread[Reference >> Handler,10,system] Thread: Thread[main,5,main] Thread: >> Thread[worker-13,5,main] --- >> >> This would almost point to mbean.getThreadCount() reporting a >> stale value. Is that possible? >> >> -JB- >> >> >>> Mandy >>> >> >> >> > > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJR74OmAAoJELSZyqhGiB1M4k8H/2hM5o2vVe2lfhc374IBaR5R R8i9Z2n0prBRKIqg4bTkAcllq5pmdozxwFyaEBzJtAGh9vnL7Tmojn6ksg9K+MMl bSgWSeg+gSZyymS7aE8rTVqKigH8vNOpHOogePDrUOCZGeZgJIMpmY1QcVbLeq8k mkz5mPYxEE2E7gt8cjvcXknOWeQUTyZILWGIPBfx9FL0iwBtK5h0PnfasR7bCxcR DO48USIuTxe+aN687OkAlJq9bCR6HRzWQiaSdi4ROVyrx2xYtir4n9sZtNWJwokv 3p5TdX6S64jnVZZMjbPJgCENTYMvTeRCj/8GvCYlI9KQEa9x2zhU2wIp5Zw4ag4= =4vkV -----END PGP SIGNATURE-----
