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From "Vijay (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-7030) Remove JEMallocAllocator
Date Mon, 14 Apr 2014 16:50:15 GMT


Vijay commented on CASSANDRA-7030:

Hi Bendict, 
Interesting how slow is slow in terms of Cassandra's throughput/latencies? Isn't it tradeoff
between memory fragmentation (use) vs speed? 
here is the test for memory footprint

> Remove JEMallocAllocator
> ------------------------
>                 Key: CASSANDRA-7030
>                 URL:
>             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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