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

[Gustavo Romero]

Hi Igor,

On 06/28/2018 03:26 AM, Igor Ignatyev wrote:
> Hi Gustavo,
> 
> looks fine to me.

Thanks!

Could I get a second review please?


Regards,
Gustavo

> 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
>>
>