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-3796) Speed up edit log tests by avoiding fsync()
Date Mon, 13 Aug 2012 22:52:38 GMT

    [ https://issues.apache.org/jira/browse/HDFS-3796?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13433699#comment-13433699

Todd Lipcon commented on HDFS-3796:

Hey Suresh. Nope, each junit class file runs in its own JVM. We make use of the static {}
pattern for setting log levels as well, so I think this should be considered equivalent.
> Speed up edit log tests by avoiding fsync()
> -------------------------------------------
>                 Key: HDFS-3796
>                 URL: https://issues.apache.org/jira/browse/HDFS-3796
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: test
>    Affects Versions: 3.0.0, 2.2.0-alpha
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Minor
>         Attachments: hdfs-3796.txt
> Our edit log tests are very slow because they incur a lot of fsyncs as they write out
transactions. Since fsync() has no effect except in the case of power outages or system crashes,
and we don't care about power outages in the context of tests, we can safely skip the fsync
without any loss in coverage.
> In my tests, this sped up TestEditLog by about 5x. The testFuzzSequences test case improved
from ~83 seconds with fsync to about 5 seconds without. These results are from my SSD laptop
- they are probably even more drastic on spinning media.

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


View raw message