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Date: Thu, 16 Feb 2012 00:25:00 +0000 (UTC)
From: "Todd Lipcon (Commented) (JIRA)" <jira@apache.org>
To: common-issues@hadoop.apache.org
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Subject: [jira] [Commented] (HADOOP-8069) Enable TCP_NODELAY by default for
 IPC
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    [ https://issues.apache.org/jira/browse/HADOOP-8069?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13209012#comment-13209012 ] 

Todd Lipcon commented on HADOOP-8069:
-------------------------------------

Hi Daryn. Your above descriptions sound right, except the nagle delay on Linux is 40ms rather than 200 (I think the dack delay is 200 though like you said).
I hacked up something like my #4 yesterday morning but didn't really like the way I did it so I threw it away. I'll try again soon :)
                
> Enable TCP_NODELAY by default for IPC
> -------------------------------------
>
>                 Key: HADOOP-8069
>                 URL: https://issues.apache.org/jira/browse/HADOOP-8069
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: ipc
>    Affects Versions: 0.23.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>         Attachments: hadoop-8069.txt
>
>
> I think we should switch the default for the IPC client and server NODELAY options to true. As wikipedia says:
> {quote}
> In general, since Nagle's algorithm is only a defense against careless applications, it will not benefit a carefully written application that takes proper care of buffering; the algorithm has either no effect, or negative effect on the application.
> {quote}
> Since our IPC layer is well contained and does its own buffering, we shouldn't be careless.

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