RFR: (S) 8050464: G1 string deduplication tests hang/timeout and leave running processes consuming all resources

Dmitry Fazunenko dmitry.fazunenko at oracle.com
Wed Aug 27 16:48:58 UTC 2014


Thanks for review, Jon!
-- Dima

On 27.08.2014 20:06, Jon Masamitsu wrote:
>
> On 8/27/2014 8:23 AM, Dmitry Fazunenko wrote:
>> Jon,
>>
>> My patch fixes the original problem: tests will fail instead, not 
>> hang up.
>> Printing extra debug info is a different story, and should require a 
>> separate RFE.
>
> Agreed.
>
>> To print char[] addresses WhiteBoxAPI needs to be used, without it 
>> only following data could be printed out:
>>
>> String   'DeduplicationTestString:7:XXXXXXXXXXXXXXXXXXXXXXXX' has not 
>> deduplicated
>>     char1[]: [C at 7ea987ac
>>     char2[]: [C at 12a3a380
>>
>> but I think this is valueless.
>
> I think there is some value is seeing that the two char arrays
> are different.   Maybe not enough though.  Your call on this.
>
>>
>> May be we can fix
>> http://cr.openjdk.java.net/~dfazunen/8050464/webrev.01/
>> https://bugs.openjdk.java.net/browse/JDK-8050464
>
> Changes look good.  If we see failures of the test, we can
> look at why it failed and maybe come up with some additional
> output.
>
> Reviewed.
>
> Jon
>
>
>
>>
>> and file an RFE of further improvement?
>>
>> Thanks,
>> Dima
>>
>>
>> On 07.08.2014 22:20, Jon Masamitsu wrote:
>>>
>>> On 08/07/2014 03:01 AM, Dmitry Fazunenko wrote:
>>>> Jon,
>>>>
>>>> Thanks for looking!
>>>> I love printing as much debug info as possible. But in this case I 
>>>> have nothing to add.
>>>> BTW, the deduplication tests are full of various 
>>>> System.out.prinltn(), so I think the it will be enough information 
>>>> in case of failure.
>>>>
>>>> I modified a little the code to make test fail. The jtr is 
>>>> attached. Please let me know if you believe that more data need to 
>>>> be printed.
>>>
>>> Yes, lots of output on failures.  I looked for some output that told
>>> me the addresses of the two strings (the two that don't verify)
>>> and the addresses of their char arrays.  I couldn't find it.
>>> I think if I were debugging a failure, that's the first thing I would
>>> want to see.
>>>
>>> Jon
>>>
>>>>
>>>> Thanks,
>>>> Dima
>>>>
>>>> On 06.08.2014 23:56, Jon Masamitsu wrote:
>>>>> Dima,
>>>>>
>>>>> If the test fails, can you print the strings with 
>>>>> System.out.println() or
>>>>> System.err.println()?  Any information about the strings might be
>>>>> useful to understand why deduplication didn't work or why the
>>>>> test thinks the deduplication didn't work (in case something
>>>>> happens that the test doesn't expect)?
>>>>>
>>>>> Jon
>>>>>
>>>>> On 8/6/2014 8:53 AM, Dmitry Fazunenko wrote:
>>>>>> Hi,
>>>>>>
>>>>>> Would you please look at the simple fix of String Deduplication 
>>>>>> tests.
>>>>>>
>>>>>> Description:
>>>>>>
>>>>>> When string deduplication has happened /s1.equals(s2)/ will be 
>>>>>> equivalent to /s1 == s2/
>>>>>> Deduplication is performed in a separate thread so it could be 
>>>>>> delayed a bit.
>>>>>> Tests are away about possible delay and give another chance if 
>>>>>> deduplication hasn't
>>>>>> happened by the moment of check.
>>>>>> But tests wait for deduplication in infinitive loop, so if 
>>>>>> deduplication doesn't work the tests
>>>>>> will timeout, leaving hanging VM after. Which is not very elegant.
>>>>>>
>>>>>> The fix is simple: replace infinitive loops with limited ones and 
>>>>>> report failure.
>>>>>> The logic of the tests hasn't changed.
>>>>>>
>>>>>> http://cr.openjdk.java.net/~dfazunen/8050464/webrev.01/
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8050464
>>>>>>
>>>>>> Any comments are welcome.
>>>>>>
>>>>>> Thanks,
>>>>>> Dima
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>

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