JDK-6928059 : G1: command line parameter renaming
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: hs17,7
  • Priority: P3
  • Status: Closed
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2010-02-19
  • Updated: 2013-09-18
  • Resolved: 2011-03-08
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6u21Fixed 7Fixed hs17Fixed
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We would like to have consistency in the naming of the command line parameters in G1 in two ways: first, consistency in naming and second use standard (i.e., existing non-G1) parameters where appropriate. 

This CR will cover the renaming of all our current flags that are available in the product (i.e., product, diagnostic, and experimental flags) that we want to rename. Separate CRs will cover other G1 flag changes whose implementation will be a bit more involved (i.e., it will not be just a simple renaming).

General guidelines for the parameter naming:

- All G1-only parameters is prefixed with "G1"
- concurrent refinement is referred to as "ConcRefinement"
- concurrent marking is referred to as "ConcMark"
- A G1 heap region is referred to as "HeapRegion"
- switch type of flags (i.e., the switch a service on or off) will use the "Use" form and be prefixed with "G1", e.g., G1UseAdaptiveConcRefinement
- parameters that represent milliseconds are suffixed with "Millis"
- parameters that represent percentages are suffixed with "Percent"

The Public Comments on this CR will enumerate all flag changes (that will be covered by this and the other CRs), so that we can have them in one place.

EVALUATION ChangeSet=http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/b81f3572f355,ChangeRequest=6928059

EVALUATION See Comments.

PUBLIC COMMENTS The flags that will be renamed as part of this CR are the following. Simple renaming (done as part of this CR): product: G1AdaptiveConcRefine -> G1UseAdaptiveConcRefinement G1ConcRefineGreenZone -> G1ConcRefinementGreenZone G1ConcRefineRedZone -> G1ConcRefinementRedZone G1ConcRefineServiceInterval -> G1ConcRefinementServiceIntervalMillis G1ConcRefineThresholdStep -> G1ConcRefinementThresholdStep G1ConcRefineYellowZone -> G1ConcRefinementYellowZone G1ForgetfulMMUTracker -> G1UseFixedWindowMMUTracker G1MinReservePercent -> G1ReservePercent G1ParallelRSetThreads -> G1ConcRefinementThreads G1RSUpdatePauseFractionPercent -> G1RSetUpdatingPauseTimePercent G1SATBLogBufferSize -> G1SATBBufferSize diagnostic: G1PrintRegions -> G1PrintHeapRegions G1SummarizeConcurrentMark -> G1SummarizeConcMark G1TraceConcurrentRefinement -> G1TraceConcRefinement experimental: G1ParallelRSetScanningEnabled -> G1UseParallelRSetScanning G1ParallelRSetUpdatingEnabled -> G1UseParallelRSetUpdating Others (done as part of this CR): G1ExpandByPercentOfAvailable : make it experimental until we decide the G1 heap resizing policy G1SATBProcessCompletedThreshold : turn into a develop flag G1UseScanOnlyPrefix : we're in the process of removing the scan-only prefix (see 6871109), so turn it into a develop flag meanwhile G1UseSurvivorSpaces : remove it and have survivors constantly enabled (but they can be disabled in the standard way: MaxTenuringThreshold=0, etc.) Use of existing parameters (done as part of other CRs): G1MarkStackSize -> rename to MarkStackSize (and make CMSMarkStackSize an alias of MarkStackSize) (CR 6928081) G1ParallelGCAllocBufferSize -> YoungPLABSize and OldPLABSize (we'll do this in the context of CR 6818524) G1SteadyStateUsed / G1SteadyStateUsedDelta -> remove and use InitiatingHeapOccupancyPercent (CR 6928073) ParallelMarkingThreads -> rename ConcGCThreads (and make ParallelCMSThreads an alias of ConcGCThreads) (CR 6928081) G1YoungGenSize -> remove and use NewSize / MaxNewSize / -Xmn / UseAdaptiveSizePolicy (CR 6928065)