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https://issues.apache.org/jira/browse/BEAM-690?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15751670#comment-15751670
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Stas Levin commented on BEAM-690:
---------------------------------
Hi,
I'm trying to look into it, correct me if I'm wrong, but won't having such a
back-off result in tests taking longer to complete?
Backing-off the scheduling of {{MonitorRunnable#run}} delays the detection of a
shut down performed in {{MonitorRunnable#shouldShutdown}}, called by
{{MonitorRunnable#run}}.
> Backoff in the DirectRunner Monitor if no work is Available
> -----------------------------------------------------------
>
> Key: BEAM-690
> URL: https://issues.apache.org/jira/browse/BEAM-690
> Project: Beam
> Issue Type: Bug
> Components: runner-direct
> Reporter: Thomas Groh
>
> When a Pipeline has no elements available to process, the Monitor Runnable
> will be repeatedly scheduled. Given that there is no work to be done, this
> will loop over the steps in the transform looking for timers, and prompt the
> sources to perform additional work, even though there is no work to be done.
> This consumes the entirety of a single core.
> Add a bounded backoff to rescheduling the monitor runnable if no work has
> been done since it last ran. This will reduce resource consumption on
> low-throughput Pipelines.
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