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  1. JDK
  2. JDK-8220566

AArch64: Set default vm features for Ampere eMAG CPUs

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    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 13
    • Fix Version/s: 13
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • Resolved In Build:
      b13
    • CPU:
      aarch64
    • OS:
      linux

      Description

      This vm features tuning logic is wrapped by _cpu == CPU_AMCC, Ampere Computing owns this product.
      Verification will be done on Ampere eMAG platforms.
      Suppose no direct impacts on functions at other platforms.

      --- old/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp 2019-03-12 14:04:03.162682861 +0800
      +++ new/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp 2019-03-12 14:04:02.926683992 +0800
      @@ -194,6 +194,19 @@
       
         // Enable vendor specific features
       
      + // Ampere eMAG
      + if (_cpu == CPU_AMCC && (_model == 0) && (_variant == 0x3)) {
      + if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
      + FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
      + }
      + if (FLAG_IS_DEFAULT(UseSIMDForMemoryOps)) {
      + FLAG_SET_DEFAULT(UseSIMDForMemoryOps, true);
      + }
      + if (FLAG_IS_DEFAULT(UseSIMDForArrayEquals)) {
      + FLAG_SET_DEFAULT(UseSIMDForArrayEquals, !(_revision == 1 || _revision == 2));
      + }
      + }
      +
         // ThunderX
         if (_cpu == CPU_CAVIUM && (_model == 0xA1)) {
           if (_variant == 0) _features |= CPU_DMB_ATOMICS;

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            Assignee:
            qpzhang Patrick Zhang
            Reporter:
            qpzhang Patrick Zhang
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              Created:
              Updated:
              Resolved: