RFR (S): 8079555: REDO - Determining the desired PLAB size adjusts to the the number of threads at the wrong place

sangheon.kim sangheon.kim at oracle.com
Tue Jul 7 13:40:17 UTC 2015


Thank you Jon.
I'll send it at separate email.

Sangheon


On 07/06/2015 09:05 PM, Jon Masamitsu wrote:
> Sangheon,
>
> Send me the updated patch and I'll integrate it.
>
> Jon
>
> On 7/6/2015 2:44 PM, sangheon.kim wrote:
>> Hi Jon,
>>
>> Thanks for reviewing this.
>> And I need a sponsor for this change.
>> Would you sponsor this?
>>
>> Thanks,
>> Sangheon
>>
>>
>> On 07/06/2015 02:18 PM, Jon Masamitsu wrote:
>>> Sangheon,
>>>
>>> Changes look good.
>>>
>>> Jon
>>>
>>>
>>> On 06/05/2015 03:34 PM, sangheon.kim wrote:
>>>> Hi all,
>>>>
>>>> Please review this REDO change to determine the desired PLAB size 
>>>> for current gc worker threads.
>>>> The reason for back out of previous 
>>>> change(https://bugs.openjdk.java.net/browse/JDK-8073204) was it 
>>>> wouldn't guarantee to be '>= PLAB minimum size'. So added 
>>>> MAX2(min_size(),) to guarantee that.
>>>>
>>>> Currently we calculate an optimal PLAB size with current number of 
>>>> gc workers.
>>>> When the number of workers changes dynamically 
>>>> (-XX:+UseDynamicNumberOfGCThreads), the desired PLAB size 
>>>> returned(by desired_plab_sz()) is still tuned to the number of gc 
>>>> workers that has been used previously.
>>>>
>>>> This change is, firstly calculate the desired PLAB value for a 
>>>> single gc worker and then return desired PLAB size which is 
>>>> bigger(or equal) than PLAB min size according to the current number 
>>>> of threads.
>>>>
>>>> CR:
>>>> https://bugs.openjdk.java.net/browse/JDK-8079555
>>>>
>>>> Webrev:
>>>> http://cr.openjdk.java.net/~sangheki/8079555/webrev.00/
>>>>
>>>> Test:
>>>> JPRT
>>>>
>>>> Thanks,
>>>> Sangheon
>>>
>>
>



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