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

[Harold David Seigel]

+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
>