Well, thats interesting.
The case on two hosts works fine:
$ /opt/openmpi-2.0.1-jessie-mxm-mt/bin/mpirun -np 2 -hostfile hostfile --map-by node --display-map -mca pml yalla openmpi_mxm_freeze
Data for JOB [31717,1] offset 0
======================== JOB MAP ========================
Data for node: intel1 Num slots: 1 Max slots: 0 Num procs: 1
Process OMPI jobid: [31717,1] App: 0 Process rank: 0 Bound: socket 0[core 0[hwt 0-1]]:[BB/../../../../../../../../../../..][../../../../../../../../../../../..]
Data for node: intel2 Num slots: 1 Max slots: 0 Num procs: 1
Process OMPI jobid: [31717,1] App: 0 Process rank: 1 Bound: socket 0[core 0[hwt 0-1]]:[BB/../../../../../../../../../../..][../../../../../../../../../../../..]
=============================================================
[1474616276.871628] [intel1:7883 :0] sys.c:744 MXM WARN Conflicting CPU frequencies detected, using: 2906.98
[1474616276.903256] [intel2:3181 :0] sys.c:744 MXM WARN Conflicting CPU frequencies detected, using: 3043.73
0: ready to run
1: ready to run
...
0: finished
1: finished
while the one host case does not:
$ /opt/openmpi-2.0.1-jessie-mxm-mt/bin/mpirun -np 2 --map-by node --display-map -mca pml yalla openmpi_mxm_freeze
Data for JOB [31494,1] offset 0
======================== JOB MAP ========================
Data for node: intel1 Num slots: 24 Max slots: 0 Num procs: 2
Process OMPI jobid: [31494,1] App: 0 Process rank: 0 Bound: socket 0[core 0[hwt 0-1]]:[BB/../../../../../../../../../../..][../../../../../../../../../../../..]
Process OMPI jobid: [31494,1] App: 0 Process rank: 1 Bound: socket 0[core 1[hwt 0-1]]:[../BB/../../../../../../../../../..][../../../../../../../../../../../..]
=============================================================
[1474615276.877829] [intel1:7723 :0] sys.c:744 MXM WARN Conflicting CPU frequencies detected, using: 2971.04
[1474615276.877833] [intel1:7724 :0] sys.c:744 MXM WARN Conflicting CPU frequencies detected, using: 2971.04
0: ready to run
1: ready to run
...
freeze
Since we are normally using a single host and just in extreme cases two or more hosts, a solution for the single host would be appreciated.