RFR (XS): 8129518: Remove ParOldGC tests from the jprt hotspot testset

[Bengt Rutisson]

Hi David,

On 2015-06-23 07:43, David Holmes wrote:
> Hi Mikael,
>
> On 23/06/2015 8:47 AM, Mikael Vidstedt wrote:
>>
>> Please review the following small change which removes all the ParOldGC
>> test targets from the jprt hotspot testset. The ParOldGC tests are run
>> with the -XX:+UseParallelOldGC flag, but that has for some time already
>> been the default when using the Parallel GC, and there are already
>> corresponding tests which already test that configuration - namely the
>> ParallelGC ones. This change simply removes the redundant test targets.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8129518
>> Webrev:
>> http://cr.openjdk.java.net/~mikael/webrevs/8129518/webrev.00/webrev/
>
> I was a bit confused by this change but eventually figured it out: 
> turning on either of those flags also turns on the other and hence the 
> result is the same (as long as we don't explicitly turn off 
> UseParallelOldGC).

Yes, ParallelOldGC was made default for ParallelGC back in 7u40. So, 
since then it has been working the way you describe.

>
> That kind of begs the question as to what testing coverage we have for 
> -XX:+UseParallelGC -XX:-UseParallelOldGC ?


This combination (ParallelScavenge + SerialOld) is the last remaining 
supported GC combination that is a bit "odd". We deprecated the others 
in JDK 8 and removed them in JDK 9. We've always had very limited 
testing on the rarely used GC combinations. There are a couple of JTreg 
tests that are run as part of JPRT that do rudimentary testing. One of 
the nightly GC baselines also run this combination.

Thanks,
Bengt

>
> Thanks,
> David
>
>> Cheers,
>> Mikael
>>