[
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
