On Fri, Oct 06, 2006 at 03:35:30PM -0600, [EMAIL PROTECTED] wrote:
> Quoting Douglas Roberts <[EMAIL PROTECTED]>:
>
> > If you go to any of the supercomputing centers such as NCSA, SDSC, or PSC,
> > you do not see parallel java apps running on any of their machines (with the
> > occasional excepti
For SMP implementations, perhaps. I'm still not a big believer in SMP being the future for large-scale HPC, in spite of Intel's promise of an 80-core processor within 5 years:
http://news.com.com/Intel+pledges+80+cores+in+five+years/2100-1006_3-6119618.html, or perhaps even because of it. If it'
Douglas Roberts wrote:
> 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 colle
Douglas Roberts wrote:
> 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.
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
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 nume
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 studie
I knew that ;-} .On 10/7/06, Marcus G. Daniels <[EMAIL PROTECTED]> wrote:
I was just teasing..FRIAM Applied Complexity Group listservMeets Fridays 9a-11:30 at cafe at St. John's Collegelectures, archives, unsubscribe, maps at
http://www.f
Douglas Roberts wrote:
>
> etc.. There's nothing magic about Infiniband, it's just a faster,
> lower-latency Myrinet. See below for a note regarding NUMA machines.
>
Lower latency yet would be AC Hypertransport cabling (up to a meter at
full speed apparently, and then it's just a questio
Douglas Roberts wrote:
> I forgot to mention: you have to tinker the snot out of a NUMA
> application to get optimal performance. NUMA means that you have to
> pay close attention to what parts of your calculation are using which
> memory, location-wise. Non-uniform means different latency/ba
Douglas Roberts wrote:
> In other words, it will not be a general-purpose machine; rather, it
> will require specially coded applications to take advantage of it.
> [..] Finally, if previous experience with experimental new HPC
> hardware at LANL is any judge, "Roadrunner" has a bumpy road ahe
I forgot to mention: you have to tinker the snot out of a NUMA application to get optimal performance. NUMA means that you have to pay close attention to what parts of your calculation are using which memory, location-wise. Non-uniform means different latency/bandwith for different memory locati
Turns out there is a poll being taken on some mail lists on the topic
of new parallel hardware and if/how it will be used:
Parallelism: the next generation -- a small survey
http://www.nabble.com/A-small-survey-tf2337745.html
-- Owen
=
Well, first of all, Roadrunner will be a classified machine that will
be used to do nuclear weapons research at LANL. Secondly, the
architecture of the machine is an extension of existing distributed
memory cluster hardware that will hopefully leverage compact blade
configurations combined with Op
Josh writes:
> I hadn't looked at Java's GC for a while. It has gotten very
> complicated! I wonder if they have parallelized the GC.
JVM setting: -XX:UseParallelGC
Since 1.4.2
However, its not just a matter of turning on the flag! See (for example)
http://www.petefreitag.com/articles/gctuni
Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Friday, October 06, 2006 3:53 PM
To: The Friday Morning Applied Complexity Coffee Group; Douglas Roberts
Subject: Re: [FRIAM] FW: Distribution / Parallelization of ABM's
Quoting Douglas Roberts &l
Quoting Douglas Roberts <[EMAIL PROTECTED]>:
> If you go to any of the supercomputing centers such as NCSA, SDSC, or PSC,
> you do not see parallel java apps running on any of their machines (with the
> occasional exception of a parallel newbie trying, with great difficulty to
> make something wor
Quoting Douglas Roberts <[EMAIL PROTECTED]>:
> If you go to any of the supercomputing centers such as NCSA, SDSC, or PSC,
> you do not see parallel java apps running on any of their machines (with the
> occasional exception of a parallel newbie trying, with great difficulty to
> make something wor
If you go to any of the supercomputing centers such as NCSA, SDSC, or PSC, you do not see parallel java apps running on any of their machines (with the occasional exception of a parallel newbie trying, with great difficulty to make something work). The reasons:
there are few supported message pass
I came across this interesting doc on garbage collection in java:
http://java.sun.com/docs/hotspot/gc5.0/gc_tuning_5.html
which notes:
"""
...virtual machines for the JavaTM platform up to and including
version 1.3.1 do not have parallel garbage collection, so the impact
of garbage collection
I forgot to mention: the project that I am currently working on is named MIDAS, funded by NIH (
http://archive.nigms.nih.gov/research/midas.html).
One of our project teams just received a grant from the TerraGrid
community for 200,000 compute hours to develop a grid-aware version of
EpiSims. The
Laszlo sent the same request out to the NAACSOS list, too. Here's a response
that may be interesting to FRIAM-folk.
-Steve
> -Original Message-
> From: Les Gasser [mailto:[EMAIL PROTECTED]
> Sent: Friday, October 06, 2006 1:14 PM
> To: Laszlo Gulyas
> Cc: [EMAIL PROTECTED]; [EMAIL PROTE
Laszlo,My colleagues and I have been designing and implementing distributed agent based simulations for many years. Two examples of our work are TRANSIMS, http://www.transims.net/home.html
, and EpiSims, http://ndssl.vbi.vt.edu/episims.html. Both codes are written in C++ and use MPI as the messag
>From Laszlo Gulyas on the SimSoc list.
> -Original Message-
> From: Laszlo Gulyas [mailto:[EMAIL PROTECTED]
> Sent: Friday, October 06, 2006 5:32 AM
> To: [EMAIL PROTECTED]
> Subject: Distribution / Parallelization of ABM's
>
> [ Apologies for cross-postings. ]
>
> Dear Colleag
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