RFR 8078143: java/lang/management/ThreadMXBean/AllThreadIds.java fails intermittently

[Jaroslav Bachorik]

On 14.5.2015 03:57, David Holmes wrote:
> On 13/05/2015 9:46 PM, Jaroslav Bachorik wrote:
>> On 1.5.2015 21:55, Martin Buchholz wrote:
>>>
>>>
>>> On Thu, Apr 30, 2015 at 11:27 AM, Jaroslav Bachorik
>>> <jaroslav.bachorik at oracle.com <mailto:jaroslav.bachorik at oracle.com>>
>>> wrote:
>>>
>>>     On 30.4.2015 19:18, Martin Buchholz wrote:
>>>
>>>         Tests that sleep can almost always be better written some
>>> other way.
>>>         In this case, I would prefer busy-waiting with timeout until the
>>>         expected condition becomes true.
>>>
>>>
>>>     The thing is that in case of a real issue with the thread
>>> counters we
>>>     a/ would be busy-waiting till the test times out (using an arbitrary
>>>     delay is also problematic due to different performance of different
>>>     machines running with different configurations)
>>>
>>>
>>> Far less problematic (performance-wise and reliability-wise) than the
>>> fixed sleep.
>>>
>>>     b/ would get a rather confusing message about the test timing out at
>>>     the end
>>>
>>>
>>> You can easily improve the error message.
>>
>> Well, not that easily. It is not possible to get a notification when
>> JTREG decides to timeout the test. So you will get the standard JTREG
>> message and that's all.
>>
>> I was able to modify the test to wait for a given condition and provide
>> useful messages in case of mismatch and retry. For the price of an
>> increased complexity. On the other hand, the test should be much more
>> resilient to timing errors caused by slow setups.
>>
>> Updated webrev: http://cr.openjdk.java.net/~jbachorik/8078143/webrev.01
>
> Certainly increased complexity - took me quite a while to figure out
> what it all meant. :) waitForCondition should be waitTillEqual as that
> is the only condition checked (unless you'd like to make it more complex
> and pass in a Predicate ;-) ).

I started with Predicate and then realized it brought more problems than 
benefits ... and didn't rename the method afterwords. 'waitTillEquals' 
sounds good.

>
> I think the Thread.yield would be better as a short sleep

You mean not to use Thread.yield() and do Thread.sleep(1) instead?

I've moved the logical blocks into separate methods to make the test 
more explicit about the steps it takes. Incidentally, this made the 
webrev also more readable ;)

Update: http://cr.openjdk.java.net/~jbachorik/8078143/webrev.02

-JB-

>
> Thanks,
> David
> -----
>
>
>> Thanks,
>>
>> -JB-