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https://issues.apache.org/jira/browse/MAPREDUCE-6923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16113789#comment-16113789
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Hadoop QA commented on MAPREDUCE-6923:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m
18s{color} | {color:blue} Docker mode activated. {color} |
|| || || || {color:brown} Prechecks {color} ||
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m
0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:red}-1{color} | {color:red} test4tests {color} | {color:red} 0m
0s{color} | {color:red} The patch doesn't appear to include any new or modified
tests. Please justify why no new tests are needed for this patch. Also please
list what manual steps were performed to verify this patch. {color} |
|| || || || {color:brown} trunk Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 14m
32s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
18s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m
13s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 0m
19s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 0m
24s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
14s{color} | {color:green} trunk passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 0m
17s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
17s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m
17s{color} | {color:green} the patch passed {color} |
| {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m
9s{color} | {color:red}
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle:
The patch generated 1 new + 5 unchanged - 0 fixed = 6 total (was 5) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 0m
16s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m
0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 0m
30s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
11s{color} | {color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 0m
21s{color} | {color:green} hadoop-mapreduce-client-shuffle in the patch passed.
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| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
13s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black} 19m 13s{color} |
{color:black} {color} |
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|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:14b5c93 |
| JIRA Issue | MAPREDUCE-6923 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12880185/MAPREDUCE-6923.00.patch
|
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite
unit findbugs checkstyle |
| uname | Linux a8be7b9cefca 3.13.0-117-generic #164-Ubuntu SMP Fri Apr 7
11:05:26 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh
|
| git revision | trunk / f4c6b00 |
| Default Java | 1.8.0_131 |
| findbugs | v3.1.0-RC1 |
| checkstyle |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/7042/artifact/patchprocess/diff-checkstyle-hadoop-mapreduce-project_hadoop-mapreduce-client_hadoop-mapreduce-client-shuffle.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/7042/testReport/ |
| modules | C:
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle
U:
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle
|
| Console output |
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/7042/console |
| Powered by | Apache Yetus 0.5.0 http://yetus.apache.org |
This message was automatically generated.
> YARN Shuffle I/O for small partitions
> -------------------------------------
>
> Key: MAPREDUCE-6923
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6923
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Environment: Observed in Hadoop 2.7.3 and above (judging from the
> source code of future versions), and Ubuntu 16.04.
> Reporter: Robert Schmidtke
> Assignee: Robert Schmidtke
> Attachments: MAPREDUCE-6923.00.patch
>
>
> When a job configuration results in small partitions read by each reducer
> from each mapper (e.g. 65 kilobytes as in my setup: a
> [TeraSort|https://github.com/apache/hadoop/blob/branch-2.7.3/hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/terasort/TeraSort.java]
> of 256 gigabytes using 2048 mappers and reducers each), and setting
> {code:xml}
> <property>
> <name>mapreduce.shuffle.transferTo.allowed</name>
> <value>false</value>
> </property>
> {code}
> then the default setting of
> {code:xml}
> <property>
> <name>mapreduce.shuffle.transfer.buffer.size</name>
> <value>131072</value>
> </property>
> {code}
> results in almost 100% overhead in reads during shuffle in YARN, because for
> each 65K needed, 128K are read.
> I propose a fix in
> [FadvisedFileRegion.java|https://github.com/apache/hadoop/blob/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-shuffle/src/main/java/org/apache/hadoop/mapred/FadvisedFileRegion.java#L114]
> as follows:
> {code:java}
> ByteBuffer byteBuffer = ByteBuffer.allocate(Math.min(this.shuffleBufferSize,
> trans > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) trans));
> {code}
> e.g.
> [here|https://github.com/apache/hadoop/compare/branch-2.7.3...robert-schmidtke:adaptive-shuffle-buffer].
> This sets the shuffle buffer size to the minimum value of the shuffle buffer
> size specified in the configuration (128K by default), and the actual
> partition size (65K on average in my setup). In my benchmarks this reduced
> the read overhead in YARN from about 100% (255 additional gigabytes as
> described above) down to about 18% (an additional 45 gigabytes). The runtime
> of the job remained the same in my setup.
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