RFR: 8269032: Stringdedup tests are failing if the ergonomically select GC does not support it [v2]

[Thomas Schatzl]

On Thu, 15 Jul 2021 06:58:43 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Please review this change to the string deduplication tests' handling of an
>> ergonomically chosen GC.  They were assuming G1 would be chosen in that
>> case, but that's wrong of course.  The test machine might not be a server
>> class machine, or G1 might not be included in the build.
>> 
>> Each test now has a second test declaration comment for handling the case
>> where no GC is specified by the jtreg invocation.  This second declaration
>> will force the use of G1 by the test if G1 is supported by the VM.
>> 
>> I looked into trying to be more clever and selecting a different GC if G1 is
>> not supported by the VM, but that ended up making the tests a lot more
>> messy, and doesn't seem like that important a use-case at this time.  A
>> better long-term solution would be to make all the GCs (except Epsilon)
>> support string deduplication, so we don't care which GC gets ergonomically
>> chosen.  But that's not happening today.
>> 
>> Testing:
>> Ran the string deduplication tests with various configurations: (1)
>> explicitly use G1 (2) no explicit GC, (3) no explicit GC with
>> -XX:+NeverActAsServerClassMachine.
>
> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
> 
>   separate test class per gc

Still good.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4603