G1:long remark pauses

Thomas Viessmann thomas.viessmann at oracle.com
Fri May 16 11:10:38 UTC 2014


Hi Bengt,

Well, that's already done and it did improve things.

argv[21]: -XX:+ParallelRefProcEnabled
argv[22]: -XX:ParallelGCThreads=48

before -XX:+ParallelRefProcEnabled was set the stop times were in the range of 20 to 60 seconds.
The application is a Cacao by Oracle. So they cannot change it.

Thanks and Regards

Thomas






On 05/16/14 12:58, Bengt Rutisson wrote:
>
> Hi Thomas,
>
> It looks like the application is using a lot of Reference objects. The 
> time spent in remark is dominated by reference processing. See the 
> attached graph generated from the log file you sent.
>
> You can try to see if adding -XX:+ParallelRefProcEnabled improves the 
> situation.
>
> If the customer is interested in updating their application they might 
> want to see if they can reduce the number of java.lang.ref.Reference 
> objects they use.
>
> Hths,
> Bengt
>
>
> On 2014-05-16 10:26, Thomas Viessmann wrote:
>> Hi,
>>
>>
>> I've been tuning a Java 7u51, Solaris 10, T4 system with 24G heap.
>> My customer is not very happy with the remark pauses of  up to 2 
>> seconds.
>>  -XX:ParallelGCThreads=48 turned out to be the optimum. Here is the 
>> log file
>> which contains the java args at the top:
>>
>> http://aubing.de.oracle.com/gclog/gc_log_03052014.log
>>
>> Any idea to drive the remark stop times further down?
>>
>>
>> Thanks and Regards
>>
>> Thomas
>

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