RFR(s): 8038461: Test gc/g1/TestStringDeduplicationMemoryUsage.java fails with unexpected memory usage

[Jon Masamitsu]

Per,

Is there a way you could get generateString() to return the
sum of the sizes of the strings (minus 1 string)?  Instead of the doing
the calculation of bytesSaved?

Jon

On 4/1/14 12:54 AM, Per Liden wrote:
> Thanks Stefan! Need one more Review.
>
> /Per
>
> On 31 Mar 2014, at 10:49, Stefan Johansson <stefan.johansson at oracle.com> wrote:
>
>> Looks good!
>>
>> Stefan
>>
>> On 2014-03-28 14:41, Per Liden wrote:
>>> Hi,
>>>
>>> Could I please have this test fix reviewed.
>>>
>>> Summary: The test in question tries to calculate the amount of memory saved when using string deduplication. The problem is that the JVM doing this calculation could be running without compressed class pointers when the JVM doing the actual string deduplication is running with compressed class pointers. When this happens the JVMs will have different views on the size of an array header, which in the end makes the calculation incorrect and the test thinks the deduplication failed. Exactly this situation happened in a nightly test run. This fix makes sure that the array header size of the JVM doing the deduplication is communicated to the JVM doing the memory savings calculation.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8038461
>>> Webrev: http://cr.openjdk.java.net/~pliden/8038461/webrev.0/
>>>
>>> /Per
>>>