hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-2533) Remove needless synchronization on FSDataSet.getBlockFile
Date Wed, 02 Nov 2011 21:01:32 GMT

    [ https://issues.apache.org/jira/browse/HDFS-2533?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13142517#comment-13142517
] 

Todd Lipcon commented on HDFS-2533:
-----------------------------------

To benchmark, I jacked up the number of iterations of TestParallelRead by a factor of 10,
and made it 100% random read instead of 90/10 random/sequential.

Results on my Core i7 Q820@173Ghz (4 codes + HT):

| Threads | Trunk | HDFS-2533              |
| 4 | 226556 KB/s  | 236065 KB/sec (1.04x) |
| 16 | 377474 KB/s | 454362 KB/sec (1.20x) |
| 8 | 410114 KB/s  | 453107 KB/sec (1.10x) |

Combined with other in-flight optimizations (HDFS-2129) the difference is even more.
                
> Remove needless synchronization on FSDataSet.getBlockFile
> ---------------------------------------------------------
>
>                 Key: HDFS-2533
>                 URL: https://issues.apache.org/jira/browse/HDFS-2533
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: data-node
>    Affects Versions: 0.23.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Minor
>         Attachments: hdfs-2533.txt
>
>
> HDFS-1148 discusses lock contention issues in FSDataset. It provides a more comprehensive
fix, converting it all to RWLocks, etc. This JIRA is for one very specific fix which gives
a decent performance improvement for TestParallelRead: getBlockFile() currently holds the
lock which is completely unnecessary.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message