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Posted to commits@cassandra.apache.org by "Benedict (JIRA)" <ji...@apache.org> on 2014/04/14 12:15:15 UTC

[jira] [Updated] (CASSANDRA-7030) Remove JEMallocAllocator

     [ https://issues.apache.org/jira/browse/CASSANDRA-7030?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Benedict updated CASSANDRA-7030:
--------------------------------

    Attachment: 7030.txt

Attaching patch that removes the IAllocator hierarchy completely, since it is unlikely to ever make sense to use an allocator other than unsafe.

> 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
>
>
> 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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