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  1. JDK
  2. JDK-8237500

Increase the G1 eager reclaim candidate selection threshold

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Details

    • Enhancement
    • Status: Open
    • P4
    • Resolution: Unresolved
    • 14, 15
    • tbd
    • hotspot
    • gc

    Description

      The selection of candidates for eager reclaim of humongous objects mostly depends on the number of remembered set entries for that humongous object.

      Currently this threshold is ergonomically set to the sparse prt entry count as gathering the number of remembered set entries for the higher level PRTs is considered too costly. This sparse prt entry count is very low, although it has increased in JDK-8223162.

      However, with JDK-8233919 this operation to get number of entries in the card set is a read of a single variable. JDK-8267836 also separates this threshold from the number of sparse prt entries. So the reason to keep the threshold low is gone.

      Look into increasing this threshold to catch more eager reclaim candidates.

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          relates to

          Enhancement - null JDK-8267933 Opportunistically recalculate remembered sets for almost-eager reclaim candidates

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Enhancement - null JDK-8223162 Improve ergonomics for Sparse PRT entry sizing

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

          Enhancement - null JDK-8267836 Separate eager reclaim remembered set threshold from G1RSetSparseRegionEntries

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

          Enhancement - null JDK-8233919 Incrementally calculate the occupied cards in a heap region remembered set

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

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              Unassigned Unassigned
              tschatzl Thomas Schatzl
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              Dates

                Created:
                Updated: