[email protected] wrote: > 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". >
Have you looked at something like Vampir for MPI profiling? Support for VampirTrace is built into OpenMPI, if you compile Open MPI wih the correct options. The rub is that I think you need to pay for a Vampir GUI to analyze the data. I've never used it myself, but I saw a demo once, and it looked pretty powerful. http://www.vampir.eu/ You might also want to look at Tau, PAPI, and Perfmon2 http://www.cs.uoregon.edu/research/tau/home.php http://icl.cs.utk.edu/papi/ http://perfmon2.sourceforge.net/ I set this up for one of my users a couple of years ago. I could be wrong, but I think Tau requires PAPI, and PAPI in turn requires the perfmon2 kernel patches. I could be wrong, since it's been a couple of years. Reading the docs above should point you in the correct direction. That's probably more than you wanted to know. -- Prentice _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
