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G1 in JDK 7 b34?

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peter__lawrey
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Joined: 2005-11-01

It has been noticed that some code has been including in this build to support G1.
Is it available for use? Is the option -XX:+UseG1GC?

Are any of these options documented somewhere?
UseG1GC ParallelGCG1AllocBufferSize G1TimeSliceMS G1MaxPauseTimeMS G1ConfidencePerc G1MarkingOverheadPerc G1AccountConcurrentOverhead G1YoungGenSize G1Gen G1PolicyVerbose G1VerifyRemSet G1VerifyConcMark G1VerifyMarkingInEvac G1EfficiencyPctCausesMark SummarizeG1ConcMark SummarizeG1RSStats SummarizeG1ZFStats TraceG1Refine G1CMStackSize G1CMRegionStackSize G1SmoothConcRefine G1SteadyStateUsed G1SteadyStateUsedDelta G1SATBLogBufferSize G1ExpandByPctOfAvail G1MinPausesBetweenMarks G1InefficientPausePct G1RSPopLimit G1ObjPopLimit G1TraceFileOverwrite G1SummarizePopularity G1NumPopularRegions G1DoAgeCohortChecks G1DirtyCardQueueMax G1ConcRSCountTraversals G1ConcRSHotCardLimit G1LogRSRegionEntries G1UseScanOnlyPrefix G1MinReservePerc G1TraceRegions G1MaxSurvivorRegions G1SATBProcessCompletedThreshold G1ConcRefine_mon G1CollectFull G1CollectForAllocation G1IncCollectionPause G1PopRegionCollectionPause

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peter__lawrey
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Joined: 2005-11-01

BTW I have tried this on Linux but it doesn't work

/usr/java/jdk1.7.0/bin> ./java -XX:+UseG1GC -version

prints

Unrecognized VM option '+UseG1GC'

mbien
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Joined: 2007-04-29

have you tired -XX:+UnlockExperimentalVMOptions?
http://hg.openjdk.java.net/jdk7/hotspot/hotspot/rev/d28aa69f0959

peter__lawrey
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Joined: 2005-11-01

Thank you mbien.

For those interested. For the same tests...
default GC => my GC pause times were 0.5 - 34 ms.
-XX:+UseConcMarkSweepGC => my GC pause times were 1.6 - 2.7 ms
-XX:+UseG1GC -XX:G1MaxPauseTimeMS=1 => my GC pause times were 3.3 - 6.1 ms