RFR(S): 8231457 Asserts on AIX because os::elapsed_counter() is not monotonic

[David Holmes]

Hi Arno,

On 26/09/2019 11:11 pm, Zeller, Arno wrote:
> Hi David,
> 
> thanks for reviewing and sponsoring. I just put the patch in our nightly test and would prefer to wait till tomorrow for the results - but I expect no issues.

No problem, just let me know when you're ready and point me to the final 
changeset. It's after 11pm for me now anyway :)

Cheers,
David

> Best regards,
> Arno
> 
>> -----Original Message-----
>> From: David Holmes <david.holmes at oracle.com>
>> Sent: Donnerstag, 26. September 2019 13:34
>> To: Zeller, Arno <arno.zeller at sap.com>; hotspot-runtime-
>> dev at openjdk.java.net
>> Subject: Re: RFR(S): 8231457 Asserts on AIX because os::elapsed_counter() is
>> not monotonic
>>
>> Hi Arno,
>>
>> On 26/09/2019 8:37 pm, Zeller, Arno wrote:
>>> Hi,
>>>
>>> we have seen assertions on AIX 7.2 on Power9 that complain about
>> negative durations. The issue seems to be caused by the implementation of
>> o::elapsed_counter() on AIX that uses gettimeofday which is not monotonic.
>> To solve the issue I prepared a small patch that let os::elapsed_counter() use
>> javaTimeNanos() which should be monotonic. I had to adjust also
>> os::elapsed_frequency() and os::elapsedTime() to be consistent.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8231457
>>> Webrev: http://cr.openjdk.java.net/~azeller/webrevs/8231457_2/
>>>
>>> I will need a sponsor for this patch.
>>
>> Changes looks good. I will sponsor this for you. Will wait for a second
>> reviewer.
>>
>> Thanks,
>> David
>>
>>
>>> Best regards,
>>> Arno
>>>