A new computer system named Ithaca has been installed by Virginia Tech's Advanced Research Computing facility (ARC). The system is scheduled to be open to the full user community by the middle of October. However, ARC is actively looking for friendly users who are interested in trying out the new facility right now!
Friendly users will be given temporary accounts (to expire 31 December). They will be encouraged to exercise the parallel MATLAB facility provided on Ithaca, to try to parellize their existing MATLAB programs, and to report back on problems and issues they encounter.
(Once Ithaca is opened to the entire research community, friendly users will be able to apply for regular accounts on their own.)
If you are interested in being considered as a "friendly Ithaca user", please go to the ARC contact site, "http://www.arc.vt.edu/arc/contact.php" and leave a short message.
One of the special features of Ithaca is that it can run the Parallel Computing Toolbox from the MathWorks. In the current configuration, a user job can request up to 64 cooperating copies of MATLAB at a time, and ARC plans to upgrade this to 128 in the near future.
While MATLAB is heavily used on the Virginia Tech campus, the ability to run MATLAB in parallel has so far been limited to desktop machines and small experimental clusters. As Ithaca becomes available to the entire community, many MATLAB users will finally be able to experience both the trials and benefits of parallel programming.
As an example, a simple test program for counting prime numbers was run on a single core of Ithaca, and required 8.7 minutes (517 seconds). As the number of cores was increased, the run time dropped in a fairly regular way, so that with 64 cores, the same program ran in 10 seconds, or about 50 times faster.
Users interested in running parallel MATLAB on Ithaca will almost certainly want to do so with an X Window interface. On Linux, Unix and Mac OS X machines, this is taken care of by including the "-X" switch in the ssh command. Users who connect from a PC will need to do so with a program like the Xwin32 program available at http://www.starnet.com/ or the Xming server available at http://sourceforge.net/projects/xming/ or other communication software that enables X windows. It is possible to use MATLAB on Ithaca without having X Windows, but it is a much reduced and awkward environment, and many desirable features will not be available in that case.
MathWorks documentation for the Parallel Computing Toolbox is available at "http://www.mathworks.com/products/parallel-computing/" .
In cooperation with Virginia Tech's FDI (Faculty Development Initiative), ARC will be presenting or hosting three workshops, of increasing levels of detail, on parallel MATLAB. The first workshop will be a simple introduction; the later ones will be presented by the MathWorks. The tentative schedules and titles are:
If you are interested in attending the training classes, please check http://www.fdi.vt.edu , the web site for Virginia Tech's Faculty Development Institute. Check under "Fall Short Courses".
Ithaca is an IBM iDataPlex 84 node system. Each node has a pair of Intel Nehalem processors, each of which in turn has 4 cores. This means the overall system includes 672 cores. The Nehalem processors run at 2.26 GHz.
Every node has at least 24 GB of RAM; 10 of the nodes have been set up with 48 GB of RAM, to facilitate large memory jobs.
Ithaca shares the file system used by System X. The operating system is a version of Linux. Parallel programming is suppored with MPI, OpenMP and parallel MATLAB. Jobs will be submitted through the same ARC queueing system used for System X.
Compilers on Ithaca include:
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