Hi everyone,

I'm running a COTS beowlulf cluster and I'm using it for CFD simulations with 
the OpenFOAM code. I'm currently writing a profiling application (a bunch of 
scripts) in Python that will use the Ganglia-python interface and try to give 
me an insight into the way machine is burdened during runs. What I'm actually 
trying to do is to profile the parallel runs of the OpenFOAM solvers. 

The app will increment the mesh density (the coarsness) of the simulation, and 
run the simulations increasing the number of cores. Right now the machine is 
miniscule: two nodes with Quad cores. The app will store the data (timing of 
the execution, the number of cores) and I will plot the diagrams to see when 
the case size and the core number is starting to drive the speedup away from 
the "linear one". 

Is this a good approach? I know that this will show just tendencies on such an 
impossible small number of nodes, but I will expand the machine soon, and then 
their increased number should make these tendencies more accurate. When I 
cross-reference the temporal data with the system status data given by the 
ganglia, I can derive conclusions like "O.K., the speedup went down because for 
the larger cases, the decomposition on max core number was more local, so the 
system bus must have been burdened, if ganglia confirms that the network is not 
being strangled for this case configuration".

Can anyone here tell me if I am at least stepping in the right direction? :) 
Please, don't say "it depends". 

Best regards, 
Tomislav Maric, (MSc Mechanical Engineering, just to clarify my ignorance 
regarding HPC)

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