hadoop-common-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Scott Carey (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-6148) Implement a pure Java CRC32 calculator
Date Wed, 15 Jul 2009 22:53:14 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-6148?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Scott Carey updated HADOOP-6148:
--------------------------------

    Attachment: TestCrc32Performance.java

New test, testing performance of many crc variants and spending more time warming up each
of them to make sure the JIT has compiled them to native.  System.gc() calls were experimented
with to make results more consistent from run to run.   Typically, I have been running this
with -Xmx512m

> Implement a pure Java CRC32 calculator
> --------------------------------------
>
>                 Key: HADOOP-6148
>                 URL: https://issues.apache.org/jira/browse/HADOOP-6148
>             Project: Hadoop Common
>          Issue Type: Improvement
>            Reporter: Owen O'Malley
>            Assignee: Todd Lipcon
>         Attachments: benchmarks20090714.txt, benchmarks20090715.txt, crc32-results.txt,
hadoop-5598-evil.txt, hadoop-5598-hybrid.txt, hadoop-5598.txt, hadoop-5598.txt, hdfs-297.txt,
PureJavaCrc32.java, PureJavaCrc32.java, PureJavaCrc32.java, PureJavaCrc32.java, PureJavaCrc32New.java,
PureJavaCrc32NewInner.java, PureJavaCrc32NewLoop.java, TestCrc32Performance.java, TestCrc32Performance.java,
TestCrc32Performance.java, TestCrc32Performance.java, TestPureJavaCrc32.java
>
>
> We've seen a reducer writing 200MB to HDFS with replication = 1 spending a long time
in crc calculation. In particular, it was spending 5 seconds in crc calculation out of a total
of 6 for the write. I suspect that it is the java-jni border that is causing us grief.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message