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  1. JDK
  2. JDK-8079555

REDO - Determining the desired PLAB size adjusts to the the number of threads at the wrong place

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Details

    • Bug
    • Status: Resolved
    • P4
    • Resolution: Fixed
    • 9
    • 9
    • hotspot
    • gc
    • b74

    Backports

      Description

        When calculating the size of the next PLAB we pass along the current number of gc workers, calculating an "optimal" PLAB size for that number of gc workers, that is fed directly to the desired PLAB size predictor.

        When the number of workers changes dynamically (with -XX:+UseDynamicNumberOfGCThreads), the desired PLAB size value returned is still tuned to the number of threads that has been used previously, losing performance.

        A better solution would be to feed the PLAB size predictor the value for a single thread, and calculate the actual desired size according to the current number of threads instead.

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            backported by

            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-8135598 REDO - Determining the desired PLAB size adjusts to the the number of threads at the wrong place

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

            Bug - A problem which impairs or prevents the functions of the product. JDK-8073204 Determining the desired PLAB size adjusts to the the number of threads at the wrong place

            • 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-8150952 Net PLAB size is clipped to max PLAB size as a whole, not on a per thread basis

            • P3 - Major loss of function.
            • Resolved

            Enhancement - null JDK-8030849 Investigate high fragmentation/waste in some situations during allocation during GC in G1

            • P3 - Major loss of function.
            • Open

            Bug - A problem which impairs or prevents the functions of the product. JDK-8257145 Performance regression with -XX:-ResizePLAB after JDK-8079555

            • P3 - Major loss of function.
            • Resolved
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                sangheki Sangheon Kim
                jwilhelm Jesper Wilhelmsson
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                  Created:
                  Updated:
                  Resolved: