In CESM, ESMF_AWARE_THREADING (ESMF's managed threading) results in hangs because of issues with how PEs that are threads are treated like full PETs in CMEPS & NUOPC at the moment, but they can't do things like query the component VM. Also, connectors built on PE lists (vs PET lists) would hang during RouteHandle creation.
In CESM, ESMF_AWARE_THREADING (ESMF's managed threading) results in hangs because of issues with how PEs that are threads are treated like full PETs in CMEPS & NUOPC at the moment, but they can't do things like query the component VM. Also, connectors built on PE lists (vs PET lists) would hang during RouteHandle creation.