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From "Gopal V (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HADOOP-9601) Support native CRC on byte arrays
Date Wed, 12 Jun 2013 14:35:22 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-9601?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Gopal V updated HADOOP-9601:
----------------------------

    Attachment: HADOOP-9601-rebase+benchmark.patch

Added benchmark code to the final patch.

The difference between native & builtin versions is approx 3x for CRC32C.

The calculateChunkedChecksums needs a similar tune-up.
                
> Support native CRC on byte arrays
> ---------------------------------
>
>                 Key: HADOOP-9601
>                 URL: https://issues.apache.org/jira/browse/HADOOP-9601
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: performance, util
>    Affects Versions: 3.0.0
>            Reporter: Todd Lipcon
>            Assignee: Gopal V
>              Labels: perfomance
>         Attachments: HADOOP-9601-bench.patch, HADOOP-9601-rebase+benchmark.patch, HADOOP-9601-trunk-rebase-2.patch,
HADOOP-9601-trunk-rebase.patch, HADOOP-9601-WIP-01.patch, HADOOP-9601-WIP-02.patch
>
>
> When we first implemented the Native CRC code, we only did so for direct byte buffers,
because these correspond directly to native heap memory and thus make it easy to access via
JNI. We'd generally assumed that accessing byte[] arrays from JNI was not efficient enough,
but now that I know more about JNI I don't think that's true -- we just need to make sure
that the critical sections where we lock the buffers are short.

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