pedropetrovitch_at_[hidden] wrote:
> Altough my question isnt directly about LAM/MPI it kind of answers me a lot
> of things that I need to know if I need to use MPI or not. Here it goes: Is
> it possible to make a parallel algorithm (using MPI) running in a single
> machine/node (with many process running on it, i.e., mpirun -np 10 main and
> only one hardware processor) to run faster than a serial one on the same
> conditions? Thanks a lot for the atention. Any help would be appreciated.
Theoretically, possibly with some very strange application designed so
that a single process doesn't use all the resources, or resources such
as cache/memory can't be made available to a single process.
Practically, no, the single node MPI speedup of a normal application is
limited to the number of separate processors (e.g. cores) on the node,
and would normally be optimized by running one process per core.
If there is an advantage for MPI over threading (e.g. OpenMP) it is
usually related to better cache and memory locality of the MPI processes.
|
