Josh posted https://github.com/open-mpi/ompi/pull/8432 last week to propagate arguments from PMIx and PRRTE into the top level configure --help, and it probably deserves more discussion.
There are three patches, the last of which renames arguments so you could (for example) specify different –with-slurm arguments to PMIx, PRRTE, and Open MPI. I would strongly encourage us not to bring in that patch. Ralph and I discussed that handling when we revamped the configure system last fall and the platform file was the only place we could think of where anything sane would happen in that case. For the one in a million situation, customers can always build external PMIx and PRRTE to achieve the same outcome. The rest of this email focuses on what we want to have happen with configure –help. By default, Autoconf’s generated configure –help provides the long format of help, with all arguments and descriptions, for the top level configure only. The Autoconf way of handling sub-configures is to expect the user to know to specify “./configure –help=recursive” to see all the arguments for sub-configure scripts. This does work correctly in Open MPI, but isn’t what users expect. I spent some time looking, and there does not appear to be a sane way to make ./configure –help=recursive the default. So that leaves us with three options: 1. Document (possibly at the end of the default –help output, definitely in the README) that you need to run –help=recursive to see the options for PMIx and PRRTE 2. Add “dummy” help options for the parameters from PMIx and PRRTE we think are worth exporting. This is likely prime for bit rot 3. Josh’s script to create a dummy help option for each argument in PMIx and PRRTE not in the top level configure. While (3) bothers me from a code complexity standpoint, it is probably the easiest on our customers. I do worry about expectation setting when those arguments don’t do anything because external PMIx/PRRTE are being built, but that is probably worth the tradeoff. Anyone else have thoughts or better ideas? Brian
