help messages so that users only see the message once instead of N
times when their MPI app crashes.
Note that there is a tradeoff here -- we now call malloc in this
particular "show the error" code path. This shouldn't usually be a
problem, because the errors typically displayed through this mechanism
are MPI API argument problems (e.g., sending a negative count to
MPI_SEND), and not memory errors. But such API argument errors could
be a consequence of of a prior memory error, so there's a nonzero
chance that the error failure will fail to print because malloc
failed. In this case, the user can disable help message aggregation
(via the orte_base_want_aggregate MCA parameter) and we'll fall back
to the no-malloc code path (but without aggregation).
Note that we won't aggregate before MPI_INIT or after MPI_FINALIZE.
So if you call an MPI function before MPI_INIT / after MPI_FINALIZE,
you'll still see the error message N times. Nothing we can do about
that; we need ORTE to do the aggregation properly (which is obviously
unavailable before MPI_INIT / after MPI_FINALIZE).
This commit was SVN r19611.
