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From Michael Hind <hi...@us.ibm.com>
Subject Re: [arch] Interpreter vs. JIT for Harmony VM
Date Thu, 22 Sep 2005 13:13:11 GMT
Santiago Gala <sgala@apache.org> wrote:

> Tomcat+Jetspeed runs (qualitatively) faster using an Optimized JikesRVM
> +classpath version in my TiBook than using IBM-jdk-1.4.2, but it
> requires 200 M heap, while IBM jdk runs it in 100 Megs.

Hi Santiago, glad to hear you are exploring this path.

One word of caution when comparing heapsizes of Jikes RVM and another JVM. 
 Since Jikes RVM is written in Java, all of the VM data and code is part 
of the same heap as the application, i.e., part of the 200MB you mention 
above.  In a C/C++ implementation this VM data/code would be part of the C 
heap, i.e., not part of the 100MB heap above. 

Thus, this comparisons really aren't apples-to-apples.

Michael Hind, Manager, Dynamic Optimization Group 
IBM Watson Research Center

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