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

[Gustavo Romero]

Hi Vladimir,

On 06/28/2018 02:43 PM, Vladimir Kozlov wrote:
> Looks good.

Thanks a lot for reviewing it. :)


Regards,
Gustavo

> Thanks,
> Vladimir
> 
> On 6/28/18 6:13 AM, Gustavo Romero wrote:
>> 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
>>>>
>>>
>>
>