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  1. JDK
  2. JDK-8273712

C2: Add mechanism for rejecting inlining of low frequency call sites and deprecate MinInliningThreshold.

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    Details

    • Type: Enhancement
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 18
    • Fix Version/s: 18
    • Component/s: hotspot
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      Description

      Currently the inlining heuristic uses absolute method invocation count to reject methods that are rarely executed (see MinInliningThreshold and its uses).
      This presents two problems:
      1. Method can be rarely used in a particular caller, yet if its total execution count is high it may be still inlined.
      2. The use of absolute counts is inherently problematic with the current compilation policy (adaptive threshold and background compilation). It leads to instabilities of inlining decisions.

      The proposed solution is to consider call site execution ratio in order to reject callees that are rarely executed. Set the old cutoff parameter (MinInliningThreshold) to 0 to essentially disable it and later deprecate it.

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              Assignee:
              iveresov Igor Veresov
              Reporter:
              iveresov Igor Veresov
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                Created:
                Updated: