On Mon, Sep 15, 2014 at 12:45 PM, Katy Ghantous <[email protected]> wrote:
> Hi, > I am using DMDA to run in parallel TS to solves a set of N equations. I am > using DMDAGetCorners in the RHSfunction with setting the stencil size at 2 > to solve a set of coupled ODEs on 30 cores. > The machine has 32 cores (2 physical CPUs with 2x8 core each with speed of > 3.4Ghz per core). > However, mpiexec with more than one core is showing no speedup. > Also at the configuring/testing stage for petsc on that machine, there was > no speedup and it only reported one node. > Is there somehting wrong with how i configured petsc or is the approach > inappropriate for the machine? > I am not sure what files (or sections of the code) you would need to be > able to answer my question. > The kind of code you describe sounds memory bandwidth limited. More information is here: http://www.mcs.anl.gov/petsc/documentation/faq.html#computers The STREAMS should give you an idea of the bandwidth, and running it on 2 procs vs 1 should give you an idea of the speedup to expect, no matter how many cores you use. Thanks, Matt > Thank you! > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
