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Subject: [OMPI users] OpenMPI-1.6.1: Warning - registering physical memry for mpi jobs
From: San B (forum.san_at_[hidden])
Date: 2012-09-05 00:42:50

       OpenMPI-1.6.1 is installed on Rocks-5.5 Linux cluster with intel
compilers and OFED-1.5.3. A sample Helloworld MPI program gives following
warning message:

/mpi/openmpi/1.6.1/intel/bin/mpirun -np 4 ./mpi
WARNING: It appears that your OpenFabrics subsystem is configured to only
allow registering part of your physical memory. This can cause MPI jobs to
run with erratic performance, hang, and/or crash.

This may be caused by your OpenFabrics vendor limiting the amount of
physical memory that can be registered. You should investigate the
relevant Linux kernel module parameters that control how much physical
memory can be registered, and increase them to allow registering all
physical memory on your machine.

See this Open MPI FAQ item for more information on these Linux kernel module

  Local host: masternode
  Registerable memory: 4096 MiB
  Total memory: 32151 MiB
Greetings: 1 of 4 from the node masternode
Greetings: 2 of 4 from the node masternode
Greetings: 3 of 4 from the node masternode
Greetings: 0 of 4 from the node masternode
[masternode:29820] 3 more processes have sent help message
help-mpi-btl-openib.txt / reg mem limit low
[masternode:29820] Set MCA parameter "orte_base_help_aggregate" to 0 to see
all help / error messages

The ulimit parameters also set to unlimited:

]# ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 278528
max locked memory (kbytes, -l) unlimited
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) unlimited
cpu time (seconds, -t) unlimited
max user processes (-u) 278528
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

The file /etc/securoty/limits.conf contains following lines:

* soft memlock unlimited
* hard memlock unlimited

But why still OpenMPI is throwing warning message wrt registered memory.

Thanks in advance