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From "Hong Tang (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MAPREDUCE-712) TextWritter example is CPU bound!!
Date Mon, 06 Jul 2009 22:35:14 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12727818#action_12727818
] 

Hong Tang commented on MAPREDUCE-712:
-------------------------------------

Besides profiling, I guess two other things you might want to try to ensure the problems are
not in either DFS or the specific input format you are using:
- Run TestDFSIO benchmark to see make sure hdfs layer does not consume all the cpus.
- Use a dummier writer that simply writes zeros to the files instead of wasting time generating
random text keys and values (which uses StringBuffer and does UTF8 convertions).

> TextWritter example is CPU bound!!
> ----------------------------------
>
>                 Key: MAPREDUCE-712
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-712
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: task
>    Affects Versions: 0.20.1, 0.21.0
>         Environment: ~200 nodes cluster
> Each node has the following configuration:
> Processors:     2 x Xeon L5420 2.50GHz (8 cores) - Harpertown C0, 64-bit, quad-core (8
CPUs)
> 4 Disks
> 16 GB RAM
> Linux 2.6
> Hadoop version: trunk
>            Reporter: Khaled Elmeleegy
>
> Running the RandomTextWritter example job ( from the examples jar) pegs the machiens'
CPUs.

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