Two jobs are pinned to the same CPU's (cores actually) on RHEL 5 U 4:

standard output file has this
evidence:

MPDBOOT DONE

[0] MPI startup(): socket data transfer mode [1] MPI
startup(): socket data transfer mode [0] MPI Startup(): process is pinned to
CPU00 on node compute-7-24.local [1] MPI Startup(): process is pinned to CPU03
on node compute-7-24.local

[0] Rank
Pid Node name Pin cpu

[0] 0
10190 compute-7-24.local 0

[0] 1
10189 compute-7-24.local 3

[0] Init(): I_MPI_DEBUG=6

[0] Init(): I_MPI_DEVICE=sock

[0] Init(): MPICH_INTERFACE_HOSTNAME=192.168.9.236

And the other says:

MPDBOOT DONE

[0] MPI startup(): socket data transfer mode [1] MPI
startup(): socket data transfer mode [1] MPI Startup(): process is pinned to
CPU03 on node compute-7-24.local [0] MPI Startup(): process is pinned to CPU00
on node compute-7-24.local

[0] Rank
Pid Node name Pin cpu

[0] 0
10283 compute-7-24.local 0

[0] 1
10282 compute-7-24.local 3

[0] Init(): I_MPI_DEBUG=6

[0] Init(): I_MPI_DEVICE=sock

[0] Init(): MPICH_INTERFACE_HOSTNAME=192.168.9.236

So we see how MPI is pinning those processes
to the same cores.

And also from those two files:

[root@compute-7-24 spool]# grep debug 37257.cronus.OU

debug: starting

debug: launch cmd= env I_MPI_JOB_TAGGED_PORT_OUTPUT=1
/opt/intel/impi/3.2.1.009/bin64/mpd.py
--ncpus=1 --myhost=compute-7-24 -e -d -s 1

debug: mpd on compute-7-24 on port 38764

debug: info for running mpd: {'ip': '192.168.9.236',
'ncpus': 1, 'list_port': 38764, 'entry_port': '', 'host': 'compute-7-24',
'entry_host': '', 'ifhn': ''}

[root@compute-7-24 spool]# grep debug 37258.cronus.OU

debug: starting

debug: launch cmd= env I_MPI_JOB_TAGGED_PORT_OUTPUT=1
/opt/intel/impi/3.2.1.009/bin64/mpd.py
--ncpus=1 --myhost=compute-7-24 -e -d -s 1

debug: mpd on compute-7-24 on port 38699

debug: info for running mpd: {'ip': '192.168.9.236',
'ncpus': 1, 'list_port': 38699, 'entry_port': '', 'host': 'compute-7-24',
'entry_host': '', 'ifhn': ''}

Thus,

Regards,

John Matrow

Wichita State University