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https://issues.apache.org/jira/browse/MAPREDUCE-5791?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13946411#comment-13946411
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Hudson commented on MAPREDUCE-5791:
-----------------------------------
FAILURE: Integrated in Hadoop-Yarn-trunk #520 (See
[https://builds.apache.org/job/Hadoop-Yarn-trunk/520/])
MAPREDUCE-5791. Shuffle phase is slow in Windows -
FadviseFileRegion::transferTo does not read disks efficiently. Contributed by
Nikola Vujic. (cnauroth:
http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1580994)
* /hadoop/common/trunk/hadoop-mapreduce-project/CHANGES.txt
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/main/java/org/apache/hadoop/mapred/FadvisedFileRegion.java
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/main/java/org/apache/hadoop/mapred/ShuffleHandler.java
*
/hadoop/common/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/test/java/org/apache/hadoop/mapred/TestFadvisedFileRegion.java
> Shuffle phase is slow in Windows - FadviseFileRegion::transferTo does not
> read disks efficiently
> ------------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5791
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5791
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: client
> Affects Versions: 3.0.0, 2.3.0
> Reporter: Nikola Vujic
> Assignee: Nikola Vujic
> Fix For: 3.0.0, 2.4.0
>
> Attachments: MAPREDUCE-5791.patch, MAPREDUCE-5791.patch,
> MAPREDUCE-5791.patch
>
>
> transferTo method in org.apache.hadoop.mapred.FadvisedFileRegion is using
> transferTo method from a FileChannel to transfer data from a disk to socket.
> This is performing slow in Windows, slower than in Linux. The reason is that
> transferTo method for the java.nio is issuing 32K IO requests all the time.
> In Windows, these 32K transfers are not optimal and we don't get the best
> performance form the underlying IO subsystem. In order to achieve better
> performance when reading from the drives, we need to read data in bigger
> chunks, 512K for example.
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