hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (HDFS-380) support for persistent connections to improve random read performance.
Date Mon, 06 Jun 2011 04:13:48 GMT

     [ https://issues.apache.org/jira/browse/HDFS-380?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Todd Lipcon resolved HDFS-380.
------------------------------

    Resolution: Duplicate

Resolving as duplicate of HDFS-941

> support for persistent connections to improve random read performance.
> ----------------------------------------------------------------------
>
>                 Key: HDFS-380
>                 URL: https://issues.apache.org/jira/browse/HDFS-380
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>         Environment: Linux 2.6.9-55  , Dual Core Opteron 280 2.4Ghz , 4GB memory
>            Reporter: George Wu
>         Attachments: pread_test.java
>
>
> preads() establish new connections per request. yourkit java profiles show that this
connection overhead is pretty significant on the DataNode. 
> I wrote a simple microbenchmark program which does many iterations of pread() from different
offsets of a large file. I hacked DFSClient/DataNode code to re-use the same connection/DataNode
request handler thread. The performance improvement was 7% when the data is served from disk
and 80% when the data is served from the OS page cache.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message