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  1. JDK
  2. JDK-8150313

aarch64: optimise array copy using SIMD instructions

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 9
    • Fix Version/s: 9
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • Resolved In Build:
      b112
    • CPU:
      aarch64
    • OS:
      linux

      Description

      This uses SIMD ldp/stp Qx, Qy instructions instead of scalar ldp/stp instructions, thereby loading/storing 32 bytes at a time instead of 16.

      It also extends the small copy code to copy 0-96 instead of 0-80 (because 80 is not divisible by 32).

      This improves performance on some micro-arches and not on others so I have provided a -XX:+UseSIMDForMemoryOps switch which defaults to false (we could look at enabling this by default for micro-arches where we know SIMD is better).

        Activity

        Hide
        hgupdate HG Updates added a comment -
        URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/dae92a905ef8
        User: enevill
        Date: 2016-03-08 15:57:33 +0000
        Show
        hgupdate HG Updates added a comment - URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/dae92a905ef8 User: enevill Date: 2016-03-08 15:57:33 +0000
        Hide
        hgupdate HG Updates added a comment -
        URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/dae92a905ef8
        User: lana
        Date: 2016-03-30 18:38:07 +0000
        Show
        hgupdate HG Updates added a comment - URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/dae92a905ef8 User: lana Date: 2016-03-30 18:38:07 +0000

          People

          • Assignee:
            enevill Ed Nevill
            Reporter:
            enevill Ed Nevill
          • Votes:
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            Watchers:
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            Dates

            • Created:
              Updated:
              Resolved: