[aarch64-port-dev ] JCStress Failure -WCAS_WCAS

[Aleksey Shipilev]

Hi Stuart,

On 09/15/2016 07:15 PM, Stuart Monteith wrote:
> These failures indicate that both actor's calls to weakCompareAndSet
> are failing. However, as the test cases don't test for that they are
> marked as "FORBIDDEN".
> 
> I don't believe that that is correct. Because the compare and sets are
> weak, they will be subject to spurious failures, and that is what I'll
> be seeing.
> 
> Would it be appropriate to set the testcases to something like the following?
> 
>     @Outcome(id = "1, 10", expect = Expect.ACCEPTABLE_SPEC, desc = "T1
> & T2 spurious failure")
> 
> and for boolean:
> 
>     @Outcome(id = "0, 0", expect = Expect.ACCEPTABLE, desc = "T1 & T2
> failed spuriously")

Agreed. This is the error in test grading. Both suggestions look fine, I
did this change:
  http://hg.openjdk.java.net/code-tools/jcstress/rev/3040c983b52c


> I might have submitted a patch, but currently I'm unable to build
> JCStress. This patch in langtools has cause the use of
> "-Xmodule:jdk.unsupported" in tests-chapter-1a/pom.xml to no longer
> work:
> 
> 8164745: javac -Xmodule compiles the module in a way that reads the
> unnamed module Summary: Ensuring proper separation between named
> modules the unnamed module when using -Xmodule

Yes, thanks. The day of reckoning is upon us for using that
Jigsaw-specific hack. Rewritten to avoid dealing with Jigsaw:
  http://hg.openjdk.java.net/code-tools/jcstress/rev/5938d81bff44


> In addition, "weakCompareAndSetVolatile" has been changed to
> "weakCompareAndSetPlain" which requires more changes to jcstress.

This, and other API fixes for VarHandles are done now. jcstress should
now be buildable with JDK 9b135 (latest EA):
  http://hg.openjdk.java.net/code-tools/jcstress/rev/162fe8f8a34c

Please let me know if you run into more problems. We would need to dust
off the VarHandles testing in jcstress pretty soon anyway.

Thanks,
-Aleksey