Inter-process I/O on dual CPU machines

Paul Milligan paul.milligan at
Mon May 21 17:36:17 PDT 2001

We are currently running the Scyld bproc system on our cluster of
8 dual P3 machines, and I am curious about how processes assigned to run
on the same slave node, but on separate CPUs, communicate with each other
using MPI.
Do they have to use the external network connection, or do they talk to
each other over the local loopback interface?

If they indeed do use the local loopback, then perhaps one could
specifically use this 'feature' to lessen I/O through the switch node.

Perhaps someone at Scyld could answer my question.


Paul A. Milligan
4th Wave Imaging
949-464-0943 x6 (work)
e-mail:	paul.milligan at

"DYNAMIC LINKING ERROR: Your mistake is now everywhere."

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