G1gc compaction algorithm

[Yu Zhang]

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 
> <mailto: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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