Hi, Am 07.10.2013 um 08:45 schrieb San B:
> I'm facing a performance issue with a scientific application(Fortran). The > issue is, it runs faster on single node but runs very slow on multiple nodes. > For example, a 16 core job on single node finishes in 1hr 2mins, but the same > job on two nodes (i.e. 8 cores per node & remaining 8 cores kept free) takes > 3hr 20mins. The code is compiled with ifort-13.1.1, openmpi-1.4.5 and intel > MKL libraries - lapack, blas, scalapack, blacs & fftw. What could be the > problem here with? How do you provide a list of hosts it should use to the application? Maybe it's now just running on only one machine - and/or can make use only of local OpenMP inside MKL (yes, OpenMP here which is bound to run on a single machine only). -- Reuti PS: Do you have 16 real cores or 8 plus Hyperthreading? > Is it possible to do any tuning in OpenMPI? FY More info: The cluster has > Intel Sandybridge processor (E5-2670), infiniband and Hyperthreading is > Enabled. Jobs are submitted thru LSF scheduler. > > Does HyperThreading causing any problem here? > > > Thanks > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
