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] [Commented] (HDFS-2080) Speed up DFS read path
Date Fri, 17 Jun 2011 22:30:48 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2080?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13051365#comment-13051365
] 

Todd Lipcon commented on HDFS-2080:
-----------------------------------

bq. The theoretical limit is supposed to be 6.4GB/s on my machine (8 bytes/3cycles)

With the "naive" implementation it's 8 bytes/3 cycles, but from what I've read the instruction
takes 1 cycle with a latency of 3 cycles -- ie you can pipeline three at the same time per
core if you order the instructions right, so long as there isn't a data dependency between
them. That's the pipelining optimization I was referencing above.


> Speed up DFS read path
> ----------------------
>
>                 Key: HDFS-2080
>                 URL: https://issues.apache.org/jira/browse/HDFS-2080
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: hdfs client
>    Affects Versions: 0.23.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>             Fix For: 0.23.0
>
>
> I've developed a series of patches that speeds up the HDFS read path by a factor of about
2.5x (~300M/sec to ~800M/sec for localhost reading from buffer cache) and also will make it
easier to allow for advanced users (eg hbase) to skip a buffer copy. 

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

        

Mime
View raw message