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  1. JDK
  2. JDK-8315503

G1: Code root scan causes long GC pauses due to imbalanced iteration

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    • gc
    • b18

        In some internal test we found that the current claiming policy of one region per thread can cause huge imbalance and very long pause times, see the log:

        [4179,965s][gc,phases ] GC(273) Evacuate Collection Set: 812,18ms
        [..]
        [4179,965s][gc,phases ] GC(273) Code Root Scan (ms): Min: 0,00, Avg: 59,03, Max: 775,12, Diff: 775,12, Sum: 944,44, Workers: 16
        [4179,965s][gc,phases ] GC(273) Object Copy (ms): Min: 26,74, Avg: 101,06, Max: 118,92, Diff: 92,18, Sum: 1616,98, Workers: 16
        [4179,965s][gc,phases ] GC(273) Termination (ms): Min: 0,03, Avg: 643,90, Max: 690,96, Diff: 690,93, Sum: 10302,47, Workers: 16
        [4179,965s][gc,phases ] GC(273) Termination Attempts: Min: 1, Avg: 1,0, Max: 1, Diff: 0, Sum:

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          		 Release Note: G1: Balance Code Root Scan Phase During Garbage Collection Sub-task Resolved Thomas Schatzl  

              tschatzl Thomas Schatzl
              tschatzl Thomas Schatzl
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