when running a ghost example (e.g. the spmv_bench from ghost-apps or a phist Driver) on our KNL System I get single core Performance only. @Dominik Ernst, @christiealappatt, does this work for you? Can you also try compiling phist+ghost and running e.g. phist_bench_stream?
GHOST correctly reports 68 cores and I explicitly set OMP_NUM_THREADS=64, but in 'top' I see 100% CPU usage instead of ~6400%.
I think it is important that this works well 'out-of-the-box' for People who try it on a KNL.