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https://issues.apache.org/jira/browse/MAPREDUCE-1906?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon updated MAPREDUCE-1906:
-----------------------------------
Component/s: tasktracker
Release Note: The minimum heartbeat interval has been dropped from 3
seconds to 300ms to increase scheduling throughput on small clusters. Users may
tune mapreduce.jobtracker.heartbeats.in.second to adjust this value. (was: The
minimum heartbeat interval has been dropped from 3 seconds to 300ms to increase
scheduling throughput on large clusters. Users may tune
mapreduce.jobtracker.heartbeats.in.second to adjust this value.)
> Lower minimum heartbeat interval for tasktracker > Jobtracker
> -------------------------------------------------------------
>
> Key: MAPREDUCE-1906
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1906
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: jobtracker, tasktracker
> Affects Versions: 0.20.1, 0.20.2
> Reporter: Scott Carey
> Assignee: Todd Lipcon
> Fix For: 0.23.0
>
> Attachments: MAPREDUCE-1906-0.21.patch, mapreduce-1906.txt,
> mapreduce-1906.txt
>
>
> I get a 0% to 15% performance increase for smaller clusters by making the
> heartbeat throttle stop penalizing clusters with less than 300 nodes.
> Between 0.19 and 0.20, the default minimum heartbeat interval increased from
> 2s to 3s. If a JobTracker is throttled at 100 heartbeats / sec for large
> clusters, why should a cluster with 10 nodes be throttled to 3.3 heartbeats
> per second?
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