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  1. Hadoop Common
  2. HADOOP-7401

Unit test TestPureJavaCRC32 warmup code warms up the not-so-important loop in PureJavaCRC32.update()

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: 0.21.0
    • Fix Version/s: 0.21.0
    • Component/s: test
    • Labels:
      None
    • Environment:

      Solaris-Sparcv9; Solaris-AMD64

    • Release Note:
      fixed warmup in the perf test.

      Description

      When the warmup code sequence in TestPureJavaCRC32.java is executed, it sends size=len=2 and due to the value of 'trials' in for loop in doBench(), the crc.update() gets run > the compile threshold, thus providing the information that 'while 0<len<7' is a hot loop and 'while len>7' is a cold loop. This brings the MB/s number for len > 7 in PureJavaCRC32.update() way down (e.g. ~28.5% for size=len=65536).

      The workaround would be to use size=len=>7 (so just having size=len=2101 ahead of size=len=2 will do the trick) in the warmup section.

        Attachments

        1. hadoop-7401.patch
          3 kB
          monica beckwith

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              • Assignee:
                mobeck monica beckwith
                Reporter:
                mobeck monica beckwith
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