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

[Gustavo Romero]

Hi,

I'm going to push it to jdk/jdk11 after running the tests if there are no objections.


Thanks,
Gustavo

On 06/28/2018 03:00 PM, Gustavo Romero wrote:
> 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
>>>>>
>>>>
>>>
>>
>