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  1. JDK
  2. JDK-8320162

Obsolete UseCounterDecay

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Details

    • CSR
    • Resolution: Approved
    • P4
    • 22
    • hotspot
    • None
    • behavioral
    • minimal
    • The flag currently has no effect => minimal risk
    • add/remove/modify command line option
    • JDK

    Description

      Summary

      Obsolete the no longer used flag UseCounterDecay and also schedule its expiration.

      Problem

      The flag UseCounterDecay has no effect as of JDK-8251462.

      Solution

      Obsolete UseCounterDecay in JDK 22 and expire it in JDK 23.

      Specification

      The relevant changes for this CSR:

      diff --git a/src/hotspot/share/runtime/arguments.cpp b/src/hotspot/share/runtime/arguments.cpp
      index c790a0022a4..a503e72d692 100644
      --- a/src/hotspot/share/runtime/arguments.cpp
      +++ b/src/hotspot/share/runtime/arguments.cpp
      @@ -529,6 +529,7 @@ static SpecialFlag const special_jvm_flags[] = {
         { "RefDiscoveryPolicy",           JDK_Version::undefined(), JDK_Version::jdk(21), JDK_Version::undefined() },
         { "MetaspaceReclaimPolicy",       JDK_Version::undefined(), JDK_Version::jdk(21), JDK_Version::undefined() },
         { "DoReserveCopyInSuperWord",     JDK_Version::undefined(), JDK_Version::jdk(22), JDK_Version::jdk(23) },
      +  { "UseCounterDecay",              JDK_Version::undefined(), JDK_Version::jdk(22), JDK_Version::jdk(23) },
      
       #ifdef LINUX
         { "UseHugeTLBFS",                 JDK_Version::undefined(), JDK_Version::jdk(22), JDK_Version::jdk(23) },
      diff --git a/src/hotspot/share/runtime/globals.hpp b/src/hotspot/share/runtime/globals.hpp
      index 17dfaee8a76..b780b040f94 100644
      --- a/src/hotspot/share/runtime/globals.hpp
      +++ b/src/hotspot/share/runtime/globals.hpp
      @@ -1220,16 +1220,9 @@ const int ObjectAlignmentInBytes = 8;
         product(bool, UseCompiler, true,                                          \
                 "Use Just-In-Time compilation")                                   \
                                                                                   \
      -  product(bool, UseCounterDecay, true,                                      \
      -          "Adjust recompilation counters")                                  \
      -                                                                            \
         develop(intx, CounterHalfLifeTime,    30,                                 \
                 "Half-life time of invocation counters (in seconds)")             \
                                                                                   \

      Full PR for reference: https://github.com/openjdk/jdk/pull/16673

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              dlunden Daniel Lunden
              lmesnik Leonid Mesnik
              David Holmes, Tobias Hartmann
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              Dates

                Created:
                Updated:
                Resolved: