Re: [OMPI users] How to justify the use MPI codes on multicore systems/PCs?

2011-12-11 Thread Tim Prince
On 12/11/2011 12:16 PM, Andreas Schäfer wrote: Hey, on an SMP box threaded codes CAN always be faster than their MPI equivalents. One reason why MPI sometimes turns out to be faster is that with MPI every process actually initializes its own data. Therefore it'll end up in the NUMA domain to

[OMPI users] Problem on 3D contiguous array with MPI_TYPE_VECTOR

2011-12-11 Thread christophe petit
Hello, I try to use MPI for solving the Fourier equation in 3D. In the code, I have the following parameters : number of domains on Ox : x_domains number of domains on Oy : y_domains number of domains on Oz : z_domains size of grid on Ox: size_x size of grid on Oy: size_y size of grid on Oz:

Re: [OMPI users] How to justify the use MPI codes on multicore systems/PCs?

2011-12-11 Thread MM
I guess, on a multicore machine, openmp/pthread code will always run faster than MPI code on the same box, even if the MPI implementation is efficient and uses a shared memory tool whereby the data is actually shared across the different process, though it's in a different way than it is shared

[OMPI users] Process mapping and affinity on the devel trunk

2011-12-11 Thread Ralph Castain
Hello all If you are using the developer's trunk or nightly tarball, or are interested in new mapping and binding options that will be included in the next feature series (1.7), then please read on. If not, then please ignore. People have raised the question of "the trunk isn't binding