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  1. JDK
  2. JDK-8027454

Do not traverse string table during G1 remark when treating them as strong roots during initial mark

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    • gc
    • b03

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      Description

        During the remark pause G1 traverses the string table, looking for dead oops. This is wasted effort because there cannot be any dead strings currently because:
        - the initial mark uses the string table as roots (at the moment unconditionally, later with class unloading conditionally)
        - SATB requires that any entries added later than initial mark and before remark must be kept live (and we are not treating them as weak roots anyway).

        So there should be no gain looking for dead string table entries at all.

        Removing this part of the remark saves ~13% of total remark pause times across a large range of FMW applications.

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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-8032234 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • 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-8033521 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • 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-8034540 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • 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-8045199 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • 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-8053204 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • 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-8032652 Do not traverse string table during G1 remark when treating them as strong roots during initial mark

            • P3 - Major loss of function.
            • Closed
            relates to

            Enhancement - null JDK-8027450 Improve time reporting in G1 remark

            • P3 - Major loss of function.
            • Resolved

            Enhancement - null JDK-8027476 Improve performance of Stringtable unlink

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

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                tschatzl Thomas Schatzl
                tschatzl Thomas Schatzl
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                  Updated:
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