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Posted to mapreduce-issues@hadoop.apache.org by "Ahmed Radwan (JIRA)" <ji...@apache.org> on 2012/11/07 04:24:13 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=13492093#comment-13492093 ]
Ahmed Radwan commented on MAPREDUCE-4469:
-----------------------------------------
Many thanks Todd for the comments! I'll be investigating these new changes and updating the patch accordingly.
> 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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