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Date: Mon, 3 Oct 2011 18:31:34 +0000 (UTC)
From: "Todd Lipcon (Commented) (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (HADOOP-7714) Add support in native libs for OS
 buffer cache management
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    [ https://issues.apache.org/jira/browse/HADOOP-7714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13119475#comment-13119475 ] 

Todd Lipcon commented on HADOOP-7714:
-------------------------------------

yea, I'd like to sprinkle some fadvises into the shuffle, too, and then do some terasorts, etc, to see if there's any appreciable speedup.
                
> Add support in native libs for OS buffer cache management
> ---------------------------------------------------------
>
>                 Key: HADOOP-7714
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7714
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: native
>    Affects Versions: 0.24.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>         Attachments: hadoop-7714-20s-prelim.txt
>
>
> Especially in shared HBase/MR situations, management of the OS buffer cache is important. Currently, running a big MR job will evict all of HBase's hot data from cache, causing HBase performance to really suffer. However, caching of the MR input/output is rarely useful, since the datasets tend to be larger than cache and not re-read often enough that the cache is used. Having access to the native calls {{posix_fadvise}} and {{sync_data_range}} on platforms where they are supported would allow us to do a better job of managing this cache.

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