diff --git a/user-guide/XCI.rst b/user-guide/XCI.rst index 4f7f94b..f4ba73a 100644 --- a/user-guide/XCI.rst +++ b/user-guide/XCI.rst @@ -20,7 +20,26 @@ Cray XC50 cabinet, codenamed XCI, containing 20’992 ARM cores. Available since Running ======= -Since the XCI system uses Cray ALPS to run jobs all compute intensive executables need to be run with ``aprun`` to run on the compute nodes otherwise the jobs can run on the MOM nodes that can cause problems. +Since the XCI system uses Cray ALPS to run jobs all compute intensive executables need to be run with ``aprun`` to run on the compute nodes otherwise the jobs can run on the MOM nodes that can cause problems. e.g + +``` +aprun -n 64 my_mpi.exe +``` + +For multithreaded OpenMP applications you could try: + +``` +export OMP_NUM_THREADS=64 +aprun -d 64 my_openmp.exe +``` + +For hybrid multithread with 64 MPI tasks and 4 OpenMP threads (using 4 hardware threads on XCI) you could use + +``` +export OMP_NUM_THREADS=4 +aprun -n 64 -d 4 -j 4 +``` + Queues ======