Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8225409

Investigate removal of the Hot Card Cache

    Details

    • Type: Enhancement
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 13
    • Fix Version/s: tbd
    • Component/s: hotspot
    • Subcomponent:
      gc

      Description

      The purpose of the Hot Card Cache is to collect often dirtied cards during mutator time.

      Anecdotal evidence indicates that the HCC does not contribute meaningfully to performance because:
      - it is very small (JDK-8135064); an application doing lots of refinement will overflow it quickly
      - an application doing little refinement will not use it

      However its data structures use a card map across the whole heap, i.e. one byte per card, which is 0.2% of the heap. That memory could be used more usefully in other places.

      Test and investigate its usefulness, also taking the concerns for JDK-8135064 into account.

      There may also be better ways that use less memory to cause the same effect.

        Attachments

          Issue Links

            Activity

              People

              • Assignee:
                Unassigned
                Reporter:
                tschatzl Thomas Schatzl
              • Votes:
                0 Vote for this issue
                Watchers:
                2 Start watching this issue

                Dates

                • Created:
                  Updated: