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https://issues.apache.org/jira/browse/HADOOP-16126?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16773424#comment-16773424
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Tsz Wo Nicholas Sze commented on HADOOP-16126:
----------------------------------------------

> Why the choice of 10ms?

It is because 10ms works well in the test.  10ms is a long time in modern 
computers.  So, it is still far away from busy waiting.

As you already aware, we have HADOOP-16127 for a better (but more complicated) 
fix.  The patch here is a safe, short term fix for the clusters which do not 
welcome big changes.

> Can you tease this out as a private constant in the IPC file, just so it's 
> less hidden deep in the code.

Will do.

> ipc.Client.stop() may sleep too long to wait for all connections
> ----------------------------------------------------------------
>
>                 Key: HADOOP-16126
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16126
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: ipc
>            Reporter: Tsz Wo Nicholas Sze
>            Assignee: Tsz Wo Nicholas Sze
>            Priority: Major
>         Attachments: c16126_20190219.patch
>
>
> {code}
> //Client.java
>   public void stop() {
>     ...
>     // wait until all connections are closed
>     while (!connections.isEmpty()) {
>       try {
>         Thread.sleep(100);
>       } catch (InterruptedException e) {
>       }
>     }
>     ...
>   }
> {code}
> In the code above, the sleep time is 100ms.  We found that simply changing 
> the sleep time to 10ms could improve a Hive job running time by 10x.



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