hadoop-common-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hadoop QA (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-7333) Performance improvement in PureJavaCrc32
Date Thu, 26 May 2011 22:14:47 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-7333?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13039964#comment-13039964

Hadoop QA commented on HADOOP-7333:

+1 overall.  Here are the results of testing the latest attachment 
  against trunk revision 1128003.

    +1 @author.  The patch does not contain any @author tags.

    +1 tests included.  The patch appears to include 3 new or modified tests.

    +1 javadoc.  The javadoc tool did not generate any warning messages.

    +1 javac.  The applied patch does not increase the total number of javac compiler warnings.

    +1 findbugs.  The patch does not introduce any new Findbugs (version 1.3.9) warnings.

    +1 release audit.  The applied patch does not increase the total number of release audit

    +1 core tests.  The patch passed core unit tests.

    +1 system test framework.  The patch passed system test framework compile.

Test results: https://builds.apache.org/hudson/job/PreCommit-HADOOP-Build/531//testReport/
Findbugs warnings: https://builds.apache.org/hudson/job/PreCommit-HADOOP-Build/531//artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output: https://builds.apache.org/hudson/job/PreCommit-HADOOP-Build/531//console

This message is automatically generated.

> Performance improvement in PureJavaCrc32
> ----------------------------------------
>                 Key: HADOOP-7333
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7333
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: util
>    Affects Versions: 0.21.0
>         Environment: Linux x64
>            Reporter: Eric Caspole
>            Assignee: Eric Caspole
>            Priority: Minor
>         Attachments: HADOOP-7333.patch, c7333_20110526.patch
> I would like to propose a small patch to 
>   org.apache.hadoop.util.PureJavaCrc32.update(byte[] b, int off, int len)
> Currently the method stores the intermediate result back into the data member "crc."
I noticed this method gets
> inlined into DataChecksum.update() and that method appears as one of the hotter methods
in a simple hprof profile collected while running terasort and gridmix.
> If the code is modified to save the temporary result into a local and just once store
the final result back into the data member, it results in slightly more efficient hotspot
> I tested this change using the the "org.apache.hadoop.util.TestPureJavaCrc32$PerformanceTest"
which is embedded in the existing unit test for this class, TestPureJavaCrc32 on a variety
of linux x64 AMD and Intel multi-socket and multi-core systems I have available to test.
> The patch removes several stores of the intermediate result to memory yielding a 0%-10%
speedup in the "org.apache.hadoop.util.TestPureJavaCrc32$PerformanceTest" which is embedded
in the existing unit test for this class, TestPureJavaCrc32.
> If you use a debug hotspot JVM with -XX:+PrintOptoAssembly, you can see the intermediate
stores such as:
> 414     movq    R9, [rsp + #24] # spill
> 419     movl    [R9 + #12 (8-bit)], RDX # int ! Field PureJavaCrc32.crc
> 41d     xorl    R10, RDX        # int
> The patch results in just one final store of the fully computed value.

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

View raw message