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https://issues.apache.org/jira/browse/HDFS-13702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16526281#comment-16526281
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Steve Loughran commented on HDFS-13702:
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bq, I didn't remove all the other FS-operation-level trace annotations (eg
open/close/listStatus/etc) since those are likely to be less high throughput
and therefore overhead not an issue.
OK, if it's low level read() stuff which is chattiest and most expensive, then
+1 to cutting this now, while we can worry about how to do it better.
BTW, does anyone have a public set of traces of IO patterns of apps/queries?
> HTrace hooks taking 10-15% CPU in DFS client when disabled
> ----------------------------------------------------------
>
> Key: HDFS-13702
> URL: https://issues.apache.org/jira/browse/HDFS-13702
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: performance
> Affects Versions: 3.0.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Priority: Major
> Attachments: hdfs-13702.patch, hdfs-13702.patch, hdfs-13702.patch
>
>
> I am seeing DFSClient.newReaderTraceScope take ~15% CPU in a teravalidate
> workload even when HTrace is disabled. This is because it stringifies several
> integers. We should avoid all allocation and stringification when htrace is
> disabled.
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