On 2024-04-02 07:13:38 +0100, Alastair McKinstry wrote: > > On 01/04/2024 23:25, Sebastian Ramacher wrote: > > > There is a transition to openmpi-5 / mpi-defaults which is stalled by the > > > t64 transition. > > > > > > It drops 32-bit support from OpenMPI. > > > > > > Because of this, I don't think the solution is to port 32-bit atomics for > > > armel/armhf, as it will be removed in a few weeks/months. > > > > > > While we didn't want the transitions to be done simultaneously, it might > > > be > > > the best answer. > > > > > > > > > What does the release team think? > > Adding another transition on top will just delay the time_t transition > > even more. So if we can avoid that, I'd prefer to not do this transition > > now. Unfortunately, uploads such as the one of pmix that no dropped > > support for 32 bit architectures (#1068211) are not really helpful. > > > > Also, #1064810 has no information on test builds with the new > > mpi-defaults on a 32 bit architecture. So has this transition been > > tested? > > > > Cheers > > OpenMPI 5 drops 32-bit support, but otherwise does not change the API/ABI. > So it is technically not a transition, but breaks 32-bit builds.
Doesn't make it better. This is not the time to do that without tests builds and bugs filed. > The solution is changing mpi-defaults to MPICH for 32-bit archs. MPICH > builds on all archs, but testing all dependencies of the change has not been > tested, and I don't know how you would do that - setting up eg ratt to > rebuild all on 32-bit archs (as everything on 64-bit will not have changed.) Beside the easy part of chaning mpi-defaults, I count 30 something packages that have explicit build dependencies on libopenmpi-dev. None of those packages has bugs filed to change to mpich on 32 bit architectures. To be honest, I don't see these two changes (changing mpi-defaults to mpich on 32 bit; breaking 32 bit build of openmpi) to be ready. It'd be preferable to reinstate a 32-bit compatible pmix and fix openmpi on 32 bit until the time_t transition is done. Cheers -- Sebastian Ramacher