[jira] [Resolved] (HBASE-22532) There's still too much cpu wasting on validating checksum even if buffer.size=65KB

["Zheng Hu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-22532?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zheng Hu resolved HBASE-22532.
------------------------------
    Resolution: Not A Problem

> There's still too much cpu wasting on validating checksum even if buffer.size=65KB
> ----------------------------------------------------------------------------------
>
>                 Key: HBASE-22532
>                 URL: https://issues.apache.org/jira/browse/HBASE-22532
>             Project: HBase
>          Issue Type: Sub-task
>            Reporter: Zheng Hu
>            Assignee: Zheng Hu
>            Priority: Major
>         Attachments: async-prof-pid-27827-cpu-3.svg, async-prof-pid-64695-cpu-1.svg
>
>
> After disabled the block cache, and with the following config: 
> {code}
>     # Disable the block cache
>     hfile.block.cache.size=0
>     hbase.ipc.server.allocator.buffer.size=66560
>     hbase.ipc.server.reservoir.minimal.allocating.size=0
> {code}
> The ByteBuff for block should be expected to be a SingleByteBuff,  which will use the hadoop native lib to validate the checksum, while in the cpu flame graph [async-prof-pid-27827-cpu-3.svg|https://issues.apache.org/jira/secure/attachment/12970683/async-prof-pid-27827-cpu-3.svg],  we can still see that about 32% CPU wasted on PureJavaCrc32#update,  which means it's not using the faster hadoop native lib.



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