Kommentare zu: Defaults or special options of different MPI implementations to remember

Von: Thomas Zeiser

Thomas Zeiser — Sat, 18 Feb 2012 10:46:19 +0000

The problems we sometimes observe with hanging processes at startup (right at the MPI_Init or the first time a larger communication occurs) or at the very end (at or after MPI_Finalise), were confirmed by an external user, too. His solution was to switch from I_MPI_FABRICS=shm:dapl to I_MPI_FABRICS=shm:ofa.

Von: Thomas Zeiser

Thomas Zeiser — Fri, 17 Feb 2012 12:39:51 +0000

At some point Intel switched the default for I_MPI_PMI_EXTENSIONS to off. I.e. for e.g. Intel MPI 4.0.3 you have to manually set I_MPI_PMI_EXTENSIONS=on to make the default OSC mpiexec version work properly.

In February 2012, Doug Johnson also implemented an “impi-helper” to provide the expected PMI_FD file descriptors. Cf. http://lists.osc.edu/pipermail/mpiexec/2012/001215.html for the alternative “-intel-bug” workaround.

Von: Thomas Zeiser

Thomas Zeiser — Sat, 11 Dec 2010 14:13:01 +0000

There are some new "bugs/incompatibilities" in Intel MPI 4.0.1.007 (i.e. Intel MPI 4.0up1): MPI-IO to lustre-based parallel filesystem now requires I_MPI_EXTRA_FILESYSTEM=on and I_MPI_EXTRA_FILESYSTEM_LIST=lustre otherwise you'll get locking-related errors. (Change in behavior confirmed by Intel.) OSC's mpiexec (0.84) does not start parallel instances but only N serial copies of your code if I_MPI_PMI_EXTENSIONS=off; however, mpiexec seems to work as expected if the default of I_MPI_PMI_EXTENSIONS=on is effective.