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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. -- This message was sent by Atlassian JIRA (v6.2#6252)