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  1. JDK
  2. JDK-8255720

Optimize bci_to_dp/-data by enabling iteration over raw DataLayouts

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    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 16
    • Fix Version/s: 16
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b23

      Description

      MethodData::bci_to_dp and ciMethodData::bci_to_data show up in startup/warmup profiles - much of the overhead allocating resource objects when iterating over ProfileData objects (next_data)

      Since most of the ProfileData block a static size determined by their DataLayout tag, providing a means to iterate over the raw DataLayout objects allow us to avoid allocating resource objects for most of the types of ProfileData.

      Experiments show this is very profitable - reducing overhead of MethodData::bci_to_dp by around 80-85% and ciMethodData::bci_to_data sometimes even more on a set of tests.

      The former is called via the compilation policy on the java thread, which means it has a direct effect on startup.

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              Assignee:
              redestad Claes Redestad
              Reporter:
              redestad Claes Redestad
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