[jira] [Commented] (HBASE-11492) The servers do not honnor the tcpNoDelay option

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-11492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14057606#comment-14057606 ] 

Hadoop QA commented on HBASE-11492:
-----------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12655015/11492.v1.patch
  against trunk revision .
  ATTACHMENT ID: 12655015

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:red}-1 tests included{color}.  The patch doesn't appear to include any new or modified tests.
                        Please justify why no new tests are needed for this patch.
                        Also please list what manual steps were performed to verify this patch.

    {color:red}-1 patch{color}.  The patch command could not apply the patch.

Console output: https://builds.apache.org/job/PreCommit-HBASE-Build/10015//console

This message is automatically generated.

> The servers do not honnor the tcpNoDelay option
> -----------------------------------------------
>
>                 Key: HBASE-11492
>                 URL: https://issues.apache.org/jira/browse/HBASE-11492
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver
>    Affects Versions: 0.98.0, 0.96.0, 0.99.0, 0.94.20
>            Reporter: Nicolas Liochon
>            Assignee: Nicolas Liochon
>            Priority: Critical
>             Fix For: 0.99.0, 0.98.5
>
>         Attachments: 11492.v1.patch
>
>
> There is an option to set tcpNoDelay, defaulted to true, but the socket channel is actually not changed. As a consequence, the server works with nagle enabled. This leads to very degraded behavior when a single connection is shared between threads. We enter into conflicts with nagle and tcp delayed ack. 
> Here is an example of performance with the PE tool plus HBASE-11491:
> {noformat}
> oneCon     #client       sleep          exeTime (seconds)                             avg latency, sleep excluded (microseconds)
> true           1               0                31                                                     310
> false          1               0                31                                                     310
> true           2               0                50                                                      500
> false          2               0               31                                                      310
> true           2                5               488 (including 200s sleeping)               2880 
> false          2               5               246  (including 200s sleeping)               460
> {noformat}
> The latency is divided by 5 when the connection is shared. This is the delayed ack kicking in. This can be fixed by really using tcp no delay.



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