Dist. y Paralelos: MPICH-G2

MPICH-G2 is a Grid-enabled implementation of the popular MPI (Message Passing Interface) framework. MPI is especially useful for problems that can be broken up into several processes running in parallel, with information exchanged between the processes as needed. The MPI programming environment handles the details of starting and shutting down processes, coordinating execution (supporting barriers and other IPC metaphors), and passing data between the processes.

MPICH-G2 uses Grid capabilities for starting processes on remote systems, for staging executables and data to remote systems, and for security. MPICH-G2 also selects the appropriate communication method (high-performance local interconnect, Internet protocol, etc.) depending on whether messages are being passed between local or remote systems.

Should I use MPICH-G2?

One important class of problems is those that are distributed by nature, that is, problems whose solutions are inherently distributed, for example, remote visualization applications in which computationally intensive work producing visualization output is performed at one location, perhaps as an MPI application running on some massively parallel processor (MPP), and the images are displayed on a remote high-end (e.g., IDesk, CAVE) device. For such problems, MPICH-G2 allows you to use MPI as your programming model.

A second class of problems is those that are distributed by design, in which you have access to multiple computers, perhaps at multiple sites connected across a WAN, and you wish couple these computers int a computational grid, or simply grid. Here MPICH-G2 can be used to run your application using (where available) vendor-supplied implementations of MPI for intramachine communication and TCP for intermachine communication.

In one scenario illustrating this second class of problems, you have a cluster of workstations. Here Globus services made available through MPICH-G2 provide an environment in which you can conveniently launch your MPI application. An example is of this scenario is the Grid Application Development Software (GrADS) Project.

In another scenario you have an MPI application that runs on a single MPP but have problem sizes that are too large for any single machine you have access to. In this situation a wide-area implementation of MPI like MPICH-G2 may help by enabling you to couple multiple MPPs in a single execution. Making efficient use of the additional CPUs that are distributed across a LAN and/or WAN typically requires modifying the application to adjust to the relatively poor latency and bandwidth introduced by the intermachine communication. Two example applications are Cactus (winner of the Gordon Bell Award at SuperComputing 2001, see MPI-Related Papers) and Overflow(D2) from Information Power Grid (IPG).

	MPICH-G2
	Northern Illinois University and Argonne National Laboratory
	Download from the MPICH website
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