Take the tour ×  I'm experimenting my distributed clustering
algorithm (implemented with MPI) on 24 computers that I set up
as a cluster using BCCD (Bootable Cluster CD) that can be
downloaded at http://bccd.net/.  I've written a batch program to
run my experiment that consists in running my algorithm several
times varying the number of nodes and the size of the input
data.  I want to know the amount of data used in the MPI
communications for each run of my algorithm so I can see how the
amount of data changes when varying the previous mentioned
parameters. And I want to do all this automatically using a
batch program.  Someone told me to use tcpdump, but I found some
difficulties in this approach.  First, I don't know how to call
tcpdump in my batch program (which is written in C++ using the
command system for making calls) before each run of my
algorithm, since tcpdump requires another terminal to run in
parallel with my application. And I can't run tcpdump in another
computer since the network uses a switc