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open-mpi
MPIRUN: use PMIx hash gds component by default
The hash PMMIx gds component has proven to be the most robust component for Open MPI so ensure its used by default.
This should probably be documented.
Errr...this is a pretty bad idea, frankly. The shmem component significantly reduces the memory footprint, especially when operating with moderate to large ppn, and is significantly faster than the hash component.
If you want to do this for a temporary thing, not to be released, then I guess it's okay - though you pretty much guarantee that the shmem version gets released untested.
Absolutely - even seen papers published that discuss it. Had a Chinese group contact me about it last year and collaborate to try and define means for reducing the footprint - eventually led to changing the attribute strings to integer indices.
Not a big deal until you get to moderate ppn. Easy to understand, though, when you do a simple calculation of the job info size for a sizable job (which can be quite a few megabytes) and then put a copy in each process (which is exactly what the hash component does). Chinese publication reported gigabytes of data storage consumed on each node of their exascale machine when using hash and running full scale. Dropped by order of ppn (which in their case was 126) when switched to shmem.