[ 
https://issues.apache.org/jira/browse/HDFS-3343?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13404272#comment-13404272
 ] 

Todd Lipcon commented on HDFS-3343:
-----------------------------------

Looks pretty good. Small comments:
- Do the new metrics have to be marked public in DataNodeMetrics.java?
- In the test case, is it safe to assert >0 nanos? eg {{waitWritable}} might 
take "0" nanos on a system with insufficiently fine-grained clock. I think we 
can leave it at just counting the NumOps to avoid a potentially flaky test.

                
> Improve metrics for DN read latency
> -----------------------------------
>
>                 Key: HDFS-3343
>                 URL: https://issues.apache.org/jira/browse/HDFS-3343
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: data-node
>            Reporter: Todd Lipcon
>            Assignee: Andrew Wang
>         Attachments: hdfs-3343-2.patch, hdfs-3343.patch
>
>
> Similar to HDFS-3170 on the write side, we should improve the metrics that 
> are generated on the DN for read latency. We should have separate metrics for 
> the time spent in {{transferTo}} vs {{waitWritable}} so that it's easy to 
> distinguish slow local disks from slow readers on the other end of the socket.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: 
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Reply via email to