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  1. JDK
  2. JDK-8241147

Conditionally enqueue elements in SATB queue

    Details

    • Type: Enhancement
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 15
    • Fix Version/s: tbd
    • Component/s: hotspot
    • Subcomponent:
      gc

      Description

      Anecdotal evidence from an old discussion with [~tonyp] and a recent paper [1] suggest that it is advantageous to filter pre-values to be put in the SATB queues based on whether they have already been marked.

      Existing overhead for the SATB barrier is already very low (~2% [2]), but maybe it is worth reducing it further.

      Investigate this.

      [1] Zhao, Blackburn, Deconstructing the Garbage-First Collector, in VEE ’20, March 17, 2020, Lausanne, Switzerland., 2020. http://users.cecs.anu.edu.au/~steveb/pubs/papers/g1-vee-2020.pdf
      [2] Shipilev, Shenandoah GC - Version 2.0 (2019): The Great Revolution, JUG Berlin-Brandenburg, Sep 2019. https://shipilev.net/talks/jugbb-Sep2019-shenandoah.pdf

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            • Assignee:
              Unassigned
              Reporter:
              tschatzl Thomas Schatzl
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              Dates

              • Created:
                Updated: