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Posted to mapreduce-issues@hadoop.apache.org by "Hadoop QA (JIRA)" <ji...@apache.org> on 2012/09/12 11:33:07 UTC
[jira] [Commented] (MAPREDUCE-4469) Resource calculation in child
tasks is CPU-heavy
[ https://issues.apache.org/jira/browse/MAPREDUCE-4469?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13453864#comment-13453864 ]
Hadoop QA commented on MAPREDUCE-4469:
--------------------------------------
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12544793/MAPREDUCE-4469_rev4.patch
against trunk revision .
-1 patch. The patch command could not apply the patch.
Console output: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/2846//console
This message is automatically generated.
> Resource calculation in child tasks is CPU-heavy
> ------------------------------------------------
>
> Key: MAPREDUCE-4469
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4469
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: performance, task
> Affects Versions: 1.0.3
> Reporter: Todd Lipcon
> Assignee: Ahmed Radwan
> Attachments: MAPREDUCE-4469.patch, MAPREDUCE-4469_rev2.patch, MAPREDUCE-4469_rev3.patch, MAPREDUCE-4469_rev4.patch
>
>
> In doing some benchmarking on a hadoop-1 derived codebase, I noticed that each of the child tasks was doing a ton of syscalls. Upon stracing, I noticed that it's spending a lot of time looping through all the files in /proc to calculate resource usage.
> As a test, I added a flag to disable use of the ResourceCalculatorPlugin within the tasks. On a CPU-bound 500G-sort workload, this improved total job runtime by about 10% (map slot-seconds by 14%, reduce slot seconds by 8%)
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