Dear all, I’ve recently compiled a parallel version of siesta 4.0b-485 using openmpi 1.10.3, and I’m seeing horrible parallel performances. I was previously building siesta with openmpi 1.6.x (on another box though) and clearly didn’t get the same behaviour. For instance, when running Tests/si001, here is the timing I get when using mpirun -np 1 (serial):
Start of run 0.000 -------------- end of scf step 1.384 -------------- end of scf step 1.589 -------------- end of scf step 1.782 -------------- end of scf step 1.987 -------------- end of scf step 2.191 etc And when using mpirun -np 2 (parallel): Start of run 0.000 -------------- end of scf step 17.349 -------------- end of scf step 32.758 -------------- end of scf step 48.386 -------------- end of scf step 64.036 -------------- end of scf step 80.265 etc I’ve used manually compiled from sources openblas 0.2.18, lapack 3.4.2, openmpi 1.10.3, and scalapack 2.0.2. I’m also using manually compiled gcc 4.8.3. I did run some scalapack tests, the ones included under scalapack-2.0.2/BLACS/TESTING and scalapack-2.0.2/TESTING, and things were apparently going well (even if it’s hard to have a feeling on the timing). Here are chunks of my arch.make which could be relevant: FC=/home/afl/local/opt/openmpi/1.10.3/bin/mpif90 FFLAGS=-O2 FPPFLAGS= -DMPI -DFC_HAVE_FLUSH -DFC_HAVE_ABORT BLAS_LIBS=/home/afl/local/opt/openblas/lib/libopenblas.so LAPACK_LIBS=/home/afl/local/opt/lapack/lib/liblapack.so BLACS_LIBS= SCALAPACK_LIBS=-L/home/afl/local/opt/scalapack/lib -lscalapack LIBS=$(SCALAPACK_LIBS) $(BLACS_LIBS) $(LAPACK_LIBS) $(BLAS_LIBS) MPI_INTERFACE=libmpi_f90.a MPI_INCLUDE=/home/afl/local/opt/openmpi/1.10.3/include/ DEFS_MPI = -DMPI Any ideas? Experience on building scalapack with a recent version of openmpi? Am I obviously doing something wrong? thanks, arthur
