RFR(S): 8132721: Add tests which check that heap counters work as expected during Humongous allocations

Kirill Zhaldybin kirill.zhaldybin at oracle.com
Tue Feb 2 15:37:19 UTC 2016


Dmitry,

Thank you for reviewing this test.

Here are a new webrev: 
http://cr.openjdk.java.net/~kzhaldyb/webrevs/JDK-8132721/webrev.05/

Could you please read comments inline?

Regards, Kirill

On 02.02.2016 15:25, Dmitry Fazunenko wrote:
> Hi Kirill,
>
> In general the test looks good.
>
> A few minor comments:
>
> 1) copyrights 2015 -> 2016
Fixed
> 2) Would you consider to move
> gcBeans.stream().mapToLong(GarbageCollectorMXBean::getCollectionCount).sum();
>
> into a separate method. You use this construct twice.
Well, I think twice is still ok and takes less lines that separate function.
>
> 3) You print debug info:
>
>              System.out.println("Counter returned that allocation used "
> + (usedMemoryAfter - usedMemoryBefore) + "; "
>                      + "expected allocation size at least " +
> expectedAllocationSize * ALLOCATION_SIZE_TOLERANCE_FACTOR);
>
>   for the sake of simplification debug in case of failure, it's better
> to print separately:
> - allocationSize, usedMemoryBefore, usedMemoryAfter.
Fixed.

>
> 4)
>
>              if (gcCountNow == gcCountBefore) {
>                  ...
>              } else {
>                  System.out.println("GC happened during allocation so
> the check is skipped");
>              }
>
> In case of an unexpected GC happens on iteration #3, all the following
> iterations will be skipped.
> But you can skip only iteration #3. For that in the 'else' branch you
> need to add
>          gcCountBefore = gcCountNow
Fixed.

>
> Thanks,
> Dima
>
>
>
> On 01.02.2016 22:04, Kirill Zhaldybin wrote:
>> Dear all,
>>
>> Could you please take a look at this test for JDK-8132721?
>>
>> The test allocates/deallocates humongous objects and checks that
>> memory counters (from Runtime and MemoryMXBean classes) work right.
>>
>> For example it's expected that after allocating HO of size
>> (G1Region/2 + 1) bytes free memory should decrease on full G1Region
>> size.
>>
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8132721
>>
>> WebRev:
>> http://cr.openjdk.java.net/~kzhaldyb/webrevs/JDK-8132721/webrev.04/
>>
>>
>> Thank you.
>> Regards, Kirill
>>
>



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