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  1. JDK
  2. JDK-8021829

DirectByteBuffer do not use Large pages

    Details

    • Type: Enhancement
    • Status: Closed
    • Priority: P3
    • Resolution: Won't Fix
    • Affects Version/s: 7
    • Fix Version/s: 9
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • OS:
      generic

      Description

      A DESCRIPTION OF THE REQUEST :
      When using the flag -XX:+UseLargePages, DirectByteBuffers don't use them. This works fine when using standard ByteBuffers.

      JUSTIFICATION :
      Since one uses DirectByteBuffer when performance is of the essence, it would be nice to have large pages enabled for those.

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      With the flag -XX:+UseLargePages, DirectByteBuffer gets allocated in the Huge page pool.
      ACTUAL -
      With the flag -XX:+UseLargePages, DirectByteBuffer uses standard pages.

      CUSTOMER SUBMITTED WORKAROUND :
      It's possible to use large pages and Direct memory by using a MappedByteBuffer that maps a file on a hugetlbfs filesytem.
      Performance is not as good as DirectByteBuffers though.

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            • Assignee:
              Unassigned
              Reporter:
              webbuggrp Webbug Group
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                Updated:
                Resolved: