RFR JDK-8152589 : java/lang/management/ThreadMXBean/Locks.java fails intermittently, blocked on wrong object

[Harsha Wardhana B]

Hi David,

Agreed that we could fix WaitingThread the way you have said, but in 
recent past, there aren't any issues reported w.r.t WaitingThread.

This test has been fixed several times (3-4) for intermittent failures 
and hence I would not like to meddle with code that is not causing any 
problems even though there is scope for refactoring.

The issue reported was with LockThreadB and hence I have provided 
possible fix for the same.

Thanks

Harsha


On Tuesday 16 August 2016 01:32 PM, David Holmes wrote:
> Hi Harsha,
>
> On 16/08/2016 4:08 PM, Harsha Wardhana B wrote:
>> Hello,
>>
>> Please review and provide comments for fix for issue,
>>
>> https://bugs.openjdk.java.net/browse/JDK-8152589
>>
>> having webrev located at
>>
>> http://cr.openjdk.java.net/~hb/8152589/webrev.00/
>
> These changes look quite good (though I have to admit I struggle to 
> read the lambda and stream code :) ).
>
> Note that like many of these kinds of tests there is an issue with 
> WaitingThread because it does not wait in a loop and so is susceptible 
> to spurious wakeups. The way to fix that is to add a "notified" 
> variable and then do:
>
> while (!notified)
>   wait();
>
> and set notified before the notify().
>
> Thanks,
> David
>
>> Fix details:
>>
>> 1. From nightly failures we see that LockThreadB was blocked on wrong
>> object. We now do a repeated check with timeout if any given thread is
>> blocked on expected object. It is possible that LockThreadB might still
>> be in Phaser call stack (Unsafe.park) when 'checkBlockedObject' is 
>> invoked.
>>
>> 2. The logs from lock free logger was never printed. It is not being
>> printed.
>>
>> 3. Any time we see failure, thread stack is being logged. This helps us
>> ascertain if failure is in test case or in the component.
>>
>> 4. Even though we had lock free logger, several ex.printStackTrace() was
>> used which could be responsible for failure. It is removed.
>>
>> 5. There were several places where tests continue to ran even after
>> failure (testFailed flag). That is fixed.
>>
>> 6. Couple of other minor refactoring.
>>
>> Thanks
>>
>> Harsha
>>