G1gc compaction algorithm

[Martin Makundi]

Hi!

UnlockDiagnosticVMOptions  is on (though later (on the right side) in the
command line). Jvm version is

java version "1.7.0_55"
Java(TM) SE Runtime Environment (build 1.7.0_55-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.55-b03, mixed mode)



2014-08-01 0:37 GMT+03:00 Yu Zhang <yu.zhang at oracle.com>:

>  Martin,
>
> These 2 need to run with  -XX:+UnlockDiagnosticVMOptions
>
> Thanks,
> Jenny
>
> On 7/31/2014 2:33 PM, Martin Makundi wrote:
>
> Hi!
>
>  G1SummarizeRSetStats does not seem to work, jvm says:
>
>  Improperly specified VM option 'G1SummarizeRSetStatsPeriod=10'
> Error: Could not create the Java Virtual Machine.
> Error: A fatal exception has occurred. Program will exit.
>
>  Same for both new options
>
>
>
> 2014-07-31 20:22 GMT+03:00 Yu Zhang <yu.zhang at oracle.com>:
>
>> Martin,
>>
>> The ScanRS for mixed gc is extremely long, 1000-9000ms.  Because it is
>> over pause time goal, minimum old regions can be added to CSet.  So mixed
>> gc is not keeping up.
>>
>> Can do a run keeping 16m region size,  no G1PrintRegionLivenessInfo, no
>> PrintHeapAtGC.  But -XX:+G1SummarizeRSetStats
>> -XX:G1SummarizeRSetStatsPeriod=10
>>
>> This should tell us more about RSet information.
>>
>> While the UpdateRS is not as bad as ScanRS, we can try to push it to the
>> concurrent threads.  Can you add -XX:G1RSetUpdatingPauseTimePercent=5.  I
>> am hoping this brings the UpdateRS down to 50ms.
>>
>>
>> Thanks,
>> Jenny
>>
>> On 7/28/2014 8:27 PM, Martin Makundi wrote:
>>
>>> Hi!
>>>
>>> We suffered a couple of Full GC's using regionsize 5M (it seems to be
>>> exact looking at logged actual parameters) and we tried the 16M option and
>>> this resulted in more severe Full GC behavior.
>>>
>>> Here is the promised log for 16 M setting:
>>> http://81.22.250.165/log/gc-16m.log
>>>
>>> We switch back to 5M hoping it will behave more nicely.
>>>
>>> **
>>> Martin
>>>
>>
>>
>
>
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