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  1. JDK
  2. JDK-8157841

aarch64: prefetch ignores cache line size

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 9
    • Fix Version/s: 9
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • Resolved In Build:
      b122
    • CPU:
      aarch64
    • OS:
      linux

      Description

      The settings for Prefetch in vm_version_aarch64.cpp ignore the cache line size and assume it is 64. On some partners HW the cache line size is 128.

      For example AllocatePrefetchStepSize is set to a constant 64, which is plainly wrong as it should be set to at least 1 cache line size.

      The variables affected are

      AllocatePrefetchDistance
      AllocatePrefetchStepSize
      PrefetchScanIntervalInBytes
      PrefetchCopyIntervalInBytes

      Also, the checking code in vm_version_aarch64.cpp do you allow you to set the value of PrefetchCopyIntervalInBytes to -1 on the command line, but instead give an error if this is attempted.

      Also, the current implementation does store prefetches before STXR for all partners implementations whereas this is only applicable to ARM A57 implementation.

        Activity

        Hide
        hgupdate HG Updates added a comment -
        URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/5282d6f65ac9
        User: enevill
        Date: 2016-05-26 09:27:09 +0000
        Show
        hgupdate HG Updates added a comment - URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/5282d6f65ac9 User: enevill Date: 2016-05-26 09:27:09 +0000
        Hide
        hgupdate HG Updates added a comment -
        URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/5282d6f65ac9
        User: lana
        Date: 2016-06-08 20:34:57 +0000
        Show
        hgupdate HG Updates added a comment - URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/5282d6f65ac9 User: lana Date: 2016-06-08 20:34:57 +0000

          People

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

            • Created:
              Updated:
              Resolved: