RFR(xs): 8205578: jtreg: Fix failing TestRTMAbortRatio on PPC64

[Igor Ignatyev]

Hi Gustavo,

looks fine to me.

Thanks,
-- Igor

> On Jun 25, 2018, at 1:29 AM, Gustavo Romero <gromero at linux.vnet.ibm.com> wrote:
> 
> Hi,
> 
> Could the following simple change be reviewed please?
> 
> bug   : https://bugs.openjdk.java.net/browse/JDK-8205578
> webrev: http://cr.openjdk.java.net/~gromero/8205578/v1/
> 
> Currently native method pageSize() is used to cause deliberate transactional
> aborts. However in test TestRTMAbortRatio pageSize() is not marked to be
> compilable and as a consequence it's never called through the code path of
> SharedRuntime::generate_native_wrapper(). As that code path is never exercised
> no 'tabort' on JNI call is executed and the test fails on Power because of fewer
> aborts than expected by the test.
> 
> I can't say for sure why that test is getting the correct number of aborts on
> x86. Nonetheless I can confirm that even on x86 the aborts do not come from the
> native wrapper, i.e. from 'xabort' in SharedRuntime::generate_native_wrapper().
> I suspect the aborts on x86 are occurring a bit latter when the native function
> is called and a "Far Call" is executed in the native method by chance and not in
> a controlled way. As far as I know there is no way to inspect the exact address
> when a transaction failed on Intel as it's possible on Power.
> 
> Anyway, marking pageSize() as compilable does not cause any regression on Intel
> (at the same time it starts to exercise the generate_native_wrapper code path)
> and makes the test pass on Power as expected.
> 
> So it fixes the following test on Power:
> 
> +Passed: compiler/rtm/locking/TestRTMAbortRatio.java
> 
> 
> Thank you and best regards,
> Gustavo
>