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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

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        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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            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8329514 G1: Code root scan causes long GC pauses due to imbalanced iteration

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

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8330652 G1: Code root scan causes long GC pauses due to imbalanced iteration

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

            Enhancement - null JDK-8317007 Add bulk removal of dead nmethods during class unloading

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

            Enhancement - null JDK-8316212 G1: Filter code root insertion into collection set during root scanning

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

            Enhancement - null JDK-8242043 G1: Naming of HeapRegionRemSet locks contribute to startup overhead

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

            Bug - A problem which impairs or prevents the functions of the product. JDK-8318720 G1: Memory leak in G1CodeRootSet after JDK-8315503

            • P3 - Major loss of function.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8317440 Lock rank checking fails when code root set is modified with the Servicelock held after JDK-8315503

            • P2 - Crashes, loss of data, severe memory leak.
            • Closed

            Bug - A problem which impairs or prevents the functions of the product. JDK-8332420 Regression in DaCapo-fop-default on linux-x64

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

            Bug - A problem which impairs or prevents the functions of the product. JDK-8326092 Pause Remark sometimes has extremely long pause times on class unloading

            • P2 - Crashes, loss of data, severe memory leak.
            • Closed

            Enhancement - null JDK-7145569 G1: optimize nmethods scanning

            • P3 - Major loss of function.
            • Resolved
            links to

            Commit Commit openjdk/jdk21u-dev/e63addbc

            Commit Commit openjdk/jdk/795e5dcc

            Review Review openjdk/jdk21u-dev/476

            Review Review openjdk/jdk/15811

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                tschatzl Thomas Schatzl
                tschatzl Thomas Schatzl
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