Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.20.0
    • Fix Version/s: 0.21.0
    • Component/s: conf
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      HADOOP-4187 introduced extra calls to Class.forName in ReflectionUtils.setConf. This caused a fairly large performance regression. Attached is a microbenchmark that shows the following timings (ms) for 100M constructions of new instances:

      Explicit construction (new Test): around ~1.6sec
      Using Test.class.newInstance: around ~2.6sec
      ReflectionUtils on 0.18.3: ~8.0sec
      ReflectionUtils on 0.20.0: ~200sec

      This illustrates the ~80x slowdown caused by HADOOP-4187.

      1. Test.java
        2 kB
        Todd Lipcon
      2. hadoop-6133-trunk.txt
        2 kB
        Todd Lipcon
      3. hadoop-6133-trunk.txt
        2 kB
        Todd Lipcon
      4. hadoop-6133-0.20.patch
        2 kB
        Todd Lipcon

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            • Assignee:
              Todd Lipcon
              Reporter:
              Todd Lipcon
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              • Created:
                Updated:
                Resolved:

                Development