600 unknowns is way too small to parallelize. Need at least 10,000 unknowns per MPI process: https://www.mcs.anl.gov/petsc/documentation/faq.html#slowerparallel
What problem are you solving? Sounds like you either compiled PETSc with debugging mode on or you just have a really terrible solver. Show us the output of -log_view. On Fri, Oct 20, 2017 at 12:47 AM Luca Verzeroli < [email protected]> wrote: > Good morning, > For my thesis I'm dealing with GALILEO, one of the clusters owned by > Cineca. http://www.hpc.cineca.it/hardware/galileo > The first question is: What is the best configuration to run petsc on this > kind of cluster? My code is only a MPI program and I would like to know if > it's better to use more nodes or more CPUs with mpirun. > This question comes from the speed up of my code using that cluster. I > have a small problem. The global matrices are 600x600. Are they too small > to see a speed up with more mpiprocess? I notice that a single core > simulation and a multi cores one take a similar time (multi core a second > more). The real problem comes when I have to run multiple simulation of the > same code changing some parameters. So I would like to speed up the single > simulation. > Any advices? > > > Luca Verzeroli >
