RFR(S) : 8243431 : use reproducible random in :vmTestbase_vm_metaspace

[Igor Ignatyev]

Hi David,

thanks for reviewing, pushed.

-- Igor

> On Apr 30, 2020, at 7:24 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> Hi Igor,
> 
> tl;dr LGTM! :)
> 
> On 1/05/2020 3:13 am, Igor Ignatyev wrote:
>> http://cr.openjdk.java.net/~iignatyev/8243431/webrev.00
>>> 27 lines changed: 23 ins; 0 del; 4 mod;
>> Hi all,
>> could you please review this small patch?
>> from JBS:
>>> this subtask is to use j.t.l.Utils.getRandomInstance() as a random number generator, where applicable, in : vmTestbase_vm_metaspace test group and marking the tests which make use of "randomness" with a proper k/w.
> 
> Okay so three kinds of changes here:
> 
> - trivial addition of randomness keyword
> - use of getRandomInstance() where applicable
> - broader changes to introduce reproducability
> 
> The last one threw me a bit as it wasn't expected from your summary. So looking at:
> 
> vmTestbase/metaspace/stressDictionary/StressDictionary.java
> 
> This test already uses a Random instance with a well-defined seed for reproducability. The problem is that is used by multiple threads so their own uses are non-deterministic due to scheduling. Hence you have now created a random instance per worker thread, seed from the shared Random instance. Okay - makes sense.
> 
> Thanks,
> David
> 
>> testing: : vmTestbase_vm_metaspace test group
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8243431
>> webrevs:
>> - code changes: http://cr.openjdk.java.net/~iignatyev//8243431/webrev.00.code
>>> 7 lines changed: 5 ins; 0 del; 2 mod;
>> - adding k/w: http://cr.openjdk.java.net/~iignatyev//8243431/webrev.00.kw
>>> 18 lines changed: 18 ins; 0 del; 0 mod;
>> - full: http://cr.openjdk.java.net/~iignatyev//8243431/webrev.00
>>> 27 lines changed: 23 ins; 0 del; 4 mod;
>> Thanks,
>> -- Igor