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  1. JDK
  2. JDK-8240873

Shenandoah: Short-cut arraycopy barriers

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    • Subcomponent:
      gc
    • Resolved In Build:
      b15
    • CPU:
      generic
    • OS:
      generic

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        Description

        The strong invariant gives us an opportunity to short-cut arraycopy-barriers:

        - if the src object is beyond the safe-iteration limit, e.g. has been allocated since evac-start, then it can not have any from-space references and thus does not require updating.
        - likewise, if the dst object is beyond TAMS, e.g. has been allocated since mark-start, then it can only have references that must have been reachable otherwise and thus don't require enqueueing in SATB.

        Short-cutting on those condition cuts out 80-90% of arraycopy slowpaths.

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                Assignee:
                rkennke Roman Kennke
                Reporter:
                rkennke Roman Kennke
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