[FRIAM] FW: Distribution / Parallelization of ABM's

[Douglas Roberts]

By the way, regarding those studies which purport to show that java is as
fast is C++:  it is easy to construct a test that does not require much
garbage collection for a java implementation.  In reality, large
agent-based  simulations written in java garbage collect.  It is therefore
easy to find studies that support either side of the argument regarding java
performance.

Here is one report that shows performance results that are more commiserate
with my own personal experience:

From: http://verify.stanford.edu/uli/java_cpp.html : a bit dated but still
relevant --

Here the results for my *400 MHz Pentium II PC* running RedHat 5.2 / 6.1:

 Version Execution Environment Execution Time  Java array JVM 1.1.5 v7
/ 1.2pre-v2 /
1.2.2 rc2 192s / 96s / 118s    HotSpot Server 1.3.0 / IBM Classic VM 1.3.0
16.7s / 10.7s    HotSpot Server 1.3.1beta-b15 16.3s  Java Vector JVM 1.1.5v7 /
1.2 pre-v2 / 1.2.2 rc2 698s / 481s / 543s    HotSpot Server 1.3.0 / IBM
Classic VM 1.3.0 46.5s / 71.5s    HotSpot Server 1.3.1beta-b15 45.6s  Java
ArrayList JVM 1.2 pre-v2 / 1.2.2 rc2 - / 260s    HotSpot Server 1.3.0 / IBM
Classic VM 1.3.0 18.8s / 62.8s    HotSpot Server 1.3.1beta-b15 18.8s  C++
pointer gcc version egcs-2.90.29 / 2.95 3.6s / 3.3s  C++ object gcc version
egcs-2.90.29 / 2.95 5.7s / 3.9s  C++ vector gcc version egcs-2.90.29 / 2.95
6.0s / 5.9s  C++ STL gcc version egcs-2.90.29 / 2.95 3.8s / 3.9s

Here more results for a *Sun Ultra 10* running Solaris 8 (SunOS 5.8).

 Version Execution Environment Execution Time  Java array HotSpot Server VM
1.3.0 17.4s  Java ArrayList HotSpot Server VM 1.3.0 26.3s  C++ pointer Sun
CC 5.1 5.22s    gcc 2.95.2 5.84s  C++ STL gcc 2.95.2 6.55s

--Doug

On 10/7/06, Douglas Roberts <doug at parrot-farm.net> wrote:
>
> Hi, Gunther.
>
> I don't want to start any language wars either.  I have seen some of these
> java performance studies as well... Regardless, I have yet to see a
> well-written real-world java application that can outperform an equivalent
> well-written C++ app, java garbage collection being one of the numerous
> reasons why.
>
> There is, after all, a reason that there are so few java apps running on
> any of the TeraGrid HPC resources.
>
> One limit of the HPJava environment is that it is primarily for use with
> data parallel or SIMD (Single Instruction Multiple Data) synchronous
> applications.  This type of parallel application is almost by definition
> *not* an agent based simulation. In reality most if not all distributed
> agent based simulations are MIMD (Multiple Instruction Multiple Data)
> asynchronous applications when implemented in an HPC environment.  HPJava
> will provide no help here.
>
> --Doug
>
> --
> Doug Roberts, RTI International
> droberts at rti.org
> doug at parrot-farm.net
> 505-455-7333 - Office
> 505-670-8195 - Cell
>
> On 10/7/06, Günther Greindl <g.greindl at aon.at> wrote:
> >
> > Hello Doug,
> >
> > I guess your friend is aware of this:
> >
> > http://www.hpjava.org/
> >
> > (a Java wrapper to interface with a native MPI package).
> > What speaks against this?
> >
> > >   2. java runs 3-4 times slower than C, C++, Fortran, and machine time
> > >   is expensive, and finally
> >
> > There have already been many studies (also published on this
> > list ;-) that this is a prejudice. Java apps can be made to
> > run just as fast as C/C++ - if you take care programming.
> > (I _don't_ want to start a language war!)
> >
> > Best Regards,
> > Günther
> >
> >
> > ============================================================
> > FRIAM Applied Complexity Group listserv
> > Meets Fridays 9a-11:30 at cafe at St. John's College
> > lectures, archives, unsubscribe, maps at http://www.friam.org
> >
>
>
>


-- 
Doug Roberts, RTI International
droberts at rti.org
doug at parrot-farm.net
505-455-7333 - Office
505-670-8195 - Cell
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