RFR (S): 8174734: Safepoint sync time did not increase

[David Holmes]

Thanks Harold.

David

On 6/06/2018 9:54 PM, Harold David Seigel wrote:
> +1
> 
> Harold
> 
> 
> On 6/5/2018 5:09 PM, coleen.phillimore at oracle.com wrote:
>>
>> Hi, This test rewrite looks good.  I'm glad there wasn't an underlying 
>> bug in the time reporting code.  Thank you for fixing this.
>>
>> Thanks,
>> Coleen
>>
>> On 6/5/18 5:44 AM, David Holmes wrote:
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8174734
>>> webrev: http://cr.openjdk.java.net/~dholmes/8174734/webrev/
>>>
>>> This is a simple logic flaw in a test that expected to see the 
>>> safepoint sync time always increase but that's not the case because 
>>> it only has millisecond resolution and only measures the time taken 
>>> to reach a safepoint (not the time consumed by the safepoint)..
>>>
>>> This was originally fixed by Coleen:
>>>
>>> http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-February/026138.html 
>>>
>>>
>>> but I was confused as to what was actually happening and so took it 
>>> over. I decided to rewrite the test to actually check what can be 
>>> relied upon:
>>>  - safepoint counts and times are always positive
>>>  - safepoint counts are accurate (at least as many as expected)
>>>  - safepoint time never goes backwards
>>>
>>> Testing:
>>>   - running the test 50 times on each platform (across a range of 
>>> machines) to see if we've ironed out the intermittent failures
>>>
>>> Thanks,
>>> David
>>
>