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Date: Wed, 14 Sep 2011 13:09:15 +0000 (UTC)
From: "Amar Kamat (JIRA)" <jira@apache.org>
To: mapreduce-issues@hadoop.apache.org
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Subject: [jira] [Created] (MAPREDUCE-3008) [Gridmix] Improve cumulative CPU
 usage emulation for short running tasks
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[Gridmix] Improve cumulative CPU usage emulation for short running tasks
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                 Key: MAPREDUCE-3008
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-3008
             Project: Hadoop Map/Reduce
          Issue Type: Sub-task
          Components: contrib/gridmix
    Affects Versions: 0.24.0
            Reporter: Amar Kamat
             Fix For: 0.24.0


CPU emulation in Gridmix fails to meet the expected target if the map has no data to sort/spill/merge. There are 2 major reasons for this:
1. The map task end immediately ends soon after the map task. The map progress is 67% while the map phase ends. 
2. Currently, the sort (comparator) doesnt emulate CPU. If the map is short lived, the CPU emulation thread (spawned from the map task in cleanup) doesn't get a chance to emulate.

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