I wanted to give everyone a heads-up about a new POSIX shared memory
that has been in the works for a while now and is ready to be pushed
o New posix component now the new default.
o May address some of the shared memory performance issues users
when OMPI's session directories are inadvertently placed on a non-
o Silent component failover.
o In the default case, if the posix component fails initialization,
mmap will be selected.
o The sysv component will only be queried for selection if it is
the mmap component (for example, -mca mpi_common_sm
sysv,posix,mmap). In the
default case, sysv will never be queried/selected.
o Per some on-list discussion, now unlinking mmaped file in both mmap
components (see: "System V Shared Memory for Open MPI: Request for
Input and Testing" thread).
o Assuming local process homogeneity with respect to all utilized
memory facilities. That is, if one local process deems a
memory facility acceptable, then ALL local processes should be
utilize that facility. As it stands, this is an important point
process dictates to all other local processes which common sm
be selected based on its own, local run-time test.
o Addressed some of George's code reuse concerns.
If there are no major objections by August 17th, I'll commit the code
Tuesday morning conference call.
Samuel K. Gutierrez
Los Alamos National Laboratory