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Hadoop QA commented on HADOOP-5170: ----------------------------------- -1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12408326/tasklimits-v2.patch against trunk revision 776904. +1 @author. The patch does not contain any @author tags. -1 tests included. The patch doesn't appear to include any new or modified tests. Please justify why no tests are needed for this patch. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 Eclipse classpath. The patch retains Eclipse classpath integrity. -1 release audit. The applied patch generated 492 release audit warnings (more than the trunk's current 491 warnings). +1 core tests. The patch passed core unit tests. -1 contrib tests. The patch failed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-vesta.apache.org/367/testReport/ Release audit warnings: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-vesta.apache.org/367/artifact/trunk/current/releaseAuditDiffWarnings.txt Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-vesta.apache.org/367/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Checkstyle results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-vesta.apache.org/367/artifact/trunk/build/test/checkstyle-errors.html Console output: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch-vesta.apache.org/367/console This message is automatically generated. > Set max map/reduce tasks on a per-job basis, either per-node or cluster-wide > ---------------------------------------------------------------------------- > > Key: HADOOP-5170 > URL: https://issues.apache.org/jira/browse/HADOOP-5170 > Project: Hadoop Core > Issue Type: New Feature > Components: mapred > Reporter: Jonathan Gray > Assignee: Matei Zaharia > Attachments: tasklimits-v2.patch, tasklimits.patch > > > There are a number of use cases for being able to do this. The focus of this > jira should be on finding what would be the simplest to implement that would > satisfy the most use cases. > This could be implemented as either a per-node maximum or a cluster-wide > maximum. It seems that for most uses, the former is preferable however > either would fulfill the requirements of this jira. > Some of the reasons for allowing this feature (mine and from others on list): > - I have some very large CPU-bound jobs. I am forced to keep the max > map/node limit at 2 or 3 (on a 4 core node) so that I do not starve the > Datanode and Regionserver. I have other jobs that are network latency bound > and would like to be able to run high numbers of them concurrently on each > node. Though I can thread some jobs, there are some use cases that are > difficult to thread (scanning from hbase) and there's significant complexity > added to the job rather than letting hadoop handle the concurrency. > - Poor assignment of tasks to nodes creates some situations where you have > multiple reducers on a single node but other nodes that received none. A > limit of 1 reducer per node for that job would prevent that from happening. > (only works with per-node limit) > - Poor mans MR job virtualization. Since we can limit a jobs resources, this > gives much more control in allocating and dividing up resources of a large > cluster. (makes most sense w/ cluster-wide limit) -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.