We have an issue with binding to cores with some applications and the default causes issues. We would, therefore, like to set the equivalent of
mpirun --bind-to none globally. I tried search for combinations of 'openmpi global settings', 'site settings', and the like on the web and ended up several times at https://www.open-mpi.org/faq/?category=sysadmin#sysadmin-mca-params That makes it look very much like MCA parameters are for network settings; see, specifically, section 4. What are MCA Parameters? Why would I set them? At some point, though, the mpirun man page, https://www.open-mpi.org/doc/v1.8/man1/mpirun.1.php, where at the end of the section titled, Mapping, Ranking, and Binding: Oh My!, it says: ----------------------------- Process binding can also be set with MCA parameters. Their usage is less convenient than that of mpirun options. On the other hand, MCA parameters can be set not only on the mpirun command line, but alternatively in a system or user mca-params.conf file or as environment variables, as described in the MCA section below. Some examples include: mpirun option MCA parameter key value --map-by core rmaps_base_mapping_policy core . . . . --bind-to none hwloc_base_binding_policy none ----------------------------- Am I correct in interpreting this to mean that, if I export OMPI_MCA_hwloc_base_binding_policy=none from the module file, the default binding will be 'none'? Equivalently, if I add a line to /ompi/install/path/etc/mca-params.conf ----- hwloc_base_binding_policy = none ----- that would do the same? The web version of the man page is for 1.8.8, and it agrees with the installed man page for our 1.8.7. However, it appears that our system man page for mpirun(1) for OpenMPI 1.8.2 has slightly different parameters. Specifically, Process binding can also be set with MCA parameters. Their usage is less convenient than that of mpirun options. On the other hand, MCA parameters can be set not only on the mpirun command line, but alterna- tively in a system or user mca-params.conf file or as environment vari- ables, as described in the MCA section below. The correspondences are: mpirun option MCA parameter key value -bycore rmaps_base_schedule_policy core -bysocket rmaps_base_schedule_policy socket -bind-to-core orte_process_binding core -bind-to-socket orte_process_binding socket -bind-to-none orte_process_binding none So for version 1.8.2, the equivalent incantations would be export OMPI_MCA_orte_process_binding=none or /ompi/install/path/v1.8.2/etc/mca-params.conf ----- orte_process_binding = none ----- Yes? Sorry to be dense about this. Thanks, -- bennet
