3.4. General Run-Time Support Notes

  • The PMIx installation must be in your PATH on all nodes (and potentially LD_LIBRARY_PATH or DYLD_LIBRARY_PATH, if libpmix is a shared library).

  • PMIx’s run-time behavior can be customized via Modular Component Architecture (MCA) parameters (see the MCA section for more information on how to get/set MCA parameter values).

  • If specified, we recommend that the ptl_tcp_if_include parameter include the loopback device (lo on many Linux platforms) to ensure that at least one intra-node transport can be found between a local client and its server. For example: export PMIX_MCA_ptl_tcp_if_include lo,eth1 ...

  • Running on nodes with different endian and/or different datatype sizes within a single PMIx-based application is supported in this release, at least from a PMIx perspective (i.e., we will pack/unpack to handle the situation). However, PMIx does not resize data when the same datatype differs in size (for example, sending a 4 byte double and receiving an 8 byte double will fail).