RFR(XXXS): 8000311: G1: ParallelGCThreads==0 broken

[John Cuthbertson]

Hi Jon,

Thanks for the review. And it was no problem adding the changes - they 
were a good idea.

JohnC

On 10/02/12 15:00, Jon Masamitsu wrote:
> John,
>
> Looks good.  Thanks for the extra changes.
>
> Jon
>
> On 10/02/12 14:15, John Cuthbertson wrote:
>> Hi Everyone,
>>
>> Here's a new webrev based upon Jon's feedback: 
>> http://cr.openjdk.java.net/~johnc/8000311/webrev.1/
>>
>> In addition to his idea of passing the number of worker threads to 
>> the (caller of) PLABStats::adjust_desired_plab_sz(), I also pass it 
>> into the G1 reference processing and enqueuing routines.
>>
>> Testing:
>> specjvm98/dacapo2006 w/ G1, ParallelGCThreads=0, heap verification
>> specjvm98/dacapo2006 w/ G1, ParallelGCThreads=n, heap verification
>> specjvm98/dacapo2006 w/ G1, ParallelGCThreads=n, heap verification, 
>> +ParallelRefProcEnabled
>> specjvm98/dacapo2006 w/ ParNew, ParallelGCThreads=n, heap verification
>>
>> Thanks,
>>
>> JohnC
>>
>>
>> On 10/01/12 15:52, Jon Masamitsu wrote:
>>> John,
>>>
>>> Would you mind passing in the no_of_gc_workers into
>>> adjust_desired_plab_sz()?
>>>
>>> G1CollectedHeap::evacuate_collection_set()
>>>     release_gc_alloc_regions(n_workers)
>>>         _survivor_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
>>>         _old_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
>>>
>>>
>>> ParNewGeneration::collect()
>>>     adjust_desired_plab_sz(n_workers)
>>>
>>> Jon
>>>
>>> On 10/01/12 14:58, John Cuthbertson wrote:
>>>> Hi Everyone,
>>>>
>>>> Can I have a couple of volunteers look over the changes for this 
>>>> fix? The webrev can be found at: 
>>>> http://cr.openjdk.java.net/~johnc/8000311/webrev.0/
>>>>
>>>> Summary:
>>>> While testing the changes for another CR, I ran into this divide by 
>>>> zero error. I decided to make a separate CR so that the change can 
>>>> be backported to hs24 - which also has the issue.
>>>>
>>>> Testing:
>>>> The original test case with and without PGCT=0 and PrintPLAB enabled.
>>>>
>>>> Thanks,
>>>>
>>>> JohnC
>>