[jira] [Comment Edited] (HBASE-12116) Hot contention spots; writing

["Nicolas Liochon (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-12116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14496031#comment-14496031 ] 

Nicolas Liochon edited comment on HBASE-12116 at 4/15/15 10:50 AM:
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I had a look at crc a while ago.
My understanding back then was that there are specific instruction in x86 processors to calculate crc, unfortunately a little bit different than the standard crc32. When I was looking at Intel/Hadoop roadmap 2 years ago, it looked like Intel was planning to do the changes in hadoop to use the hw one.

There is some info here: http://www.strchr.com/crc32_popcnt



was (Author: nkeywal):
I had a look at crc a while ago.
My understanding back then was that there are specific instruction in x86 processors to calculate crc, unfortunately a little bit different than the standard crc32. When I was looking at Intel/Hadoop roadmap 2 years ago, it looked like Intel was planning to do the changes in hadoop to use the hw one.

There are some info here: http://www.strchr.com/crc32_popcnt


> Hot contention spots; writing
> -----------------------------
>
>                 Key: HBASE-12116
>                 URL: https://issues.apache.org/jira/browse/HBASE-12116
>             Project: HBase
>          Issue Type: Bug
>            Reporter: stack
>            Assignee: stack
>         Attachments: 12116.checkForReplicas.txt, 12116.stringify.and.cache.scanner.maxsize.txt, 12116.txt, Screen Shot 2014-09-29 at 5.12.51 PM.png, Screen Shot 2014-09-30 at 10.39.34 PM.png, Screen Shot 2015-04-13 at 2.03.05 PM.png, perf.write3.svg, perf.write4.svg
>
>
> Playing with flight recorder, here are some write-time contentious synchronizations/locks (picture coming)



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