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From "Vijay (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7030) Remove JEMallocAllocator
Date Wed, 23 Apr 2014 03:27:15 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13977788#comment-13977788
] 

Vijay commented on CASSANDRA-7030:
----------------------------------

Hi Bendict, Sorry missed the update earlier.... Not sure why we are comparing synchronization,
hence i removed synchronization and here are the results.... on RHEL (32 core box) http://pastebin.com/ZXSytn70.
JEMalloc with JNI overhead is faster and efficient.

> Remove JEMallocAllocator
> ------------------------
>
>                 Key: CASSANDRA-7030
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7030
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Benedict
>            Assignee: Benedict
>            Priority: Minor
>              Labels: performance
>             Fix For: 2.1 beta2
>
>         Attachments: 7030.txt, benchmark.21.diff.txt
>
>
> JEMalloc, whilst having some nice performance properties by comparison to Doug Lea's
standard malloc algorithm in principle, is pointless in practice because of the JNA cost.
In general it is around 30x more expensive to call than unsafe.allocate(); malloc does not
have a variability of response time as extreme as the JNA overhead, so using JEMalloc in Cassandra
is never a sensible idea. I doubt if custom JNI would make it worthwhile either.
> I propose removing it.



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