Intel MPI reduce memory comsumption

Dear all,

I am currently looking into the problem of memory consumption for all-to-all based MPI software.
I far as I understand, for releases before Intel MPI 2017, we could use the DAPL_UD mode through the following variables: I_MPI_DAPL_UD and I_MPI_DAPL_UD_PROVIDER.

Since the support of DAPL has been removed in the 2019 version, what do we have to use for InfiniBand interconnect?
My additional question is also, what are the variables that reproduce the same behavior for OmniPath interconnect?

Thank you for your help.
Best,
Thomas