4
–
Running MPI on QLogic Adapters
Open MPI
IB0054606-02 A
4-17
Setting MCA Parameters
The
-mca
switch allows the passing of parameters to various Modular Component
Architecture (MCA) modules. MCA modules have direct impact on MPI programs
because they allow tunable parameters to be set at run time (such as which BTL
communication device driver to use, what parameters to pass to that BTL, and so
on.).
The
-mca
switch takes two arguments:
key
and
value
. The
key
argument
generally specifies which MCA module will receive the value. For example, the
key
btl
is used to select which BTL to be used for transporting MPI messages.
The
value
argument is the value that is passed. For example:
mpirun -mca btl tcp,self -np 1 foo
Tells Open MPI to use the
tcp
and
self
BTLs, and to run a single copy of
foo
an
allocated node.
mpirun -mca btl self -np 1 foo
Tells Open MPI to use the
self
BTL, and to run a single copy of
foo
an allocated
node.
The
-mca
switch can be used multiple times to specify different
key
and/or
value
arguments. If the same
key
is specified more than once, the
values
are
concatenated with a comma (",") separating them.
Note that the
-mca
switch is simply a shortcut for setting environment variables.
The same effect may be accomplished by setting corresponding environment
variables before running
mpirun
. The form of the environment variables that
Open MPI sets is:
OMPI_MCA_
key
=
value
Thus, the
-mca
switch overrides any previously set environment variables. The
-mca
settings similarly override MCA parameters set in these two files, which are
searched (in order):
1.
$HOME/.openmpi/mca-params.conf
: The user-supplied set of values
takes the highest precedence.
2.
$prefix/etc/openmpi-mca-params.conf:
The system-supplied set
of values has a lower precedence.
Summary of Contents for OFED+ Host
Page 1: ...IB0054606 02 A OFED Host Software Release 1 5 4 User Guide...
Page 14: ...xiv IB0054606 02 A OFED Host Software Release 1 5 4 User Guide...
Page 22: ...1 Introduction Interoperability 1 4 IB0054606 02 A...
Page 96: ...4 Running MPI on QLogic Adapters Debugging MPI Programs 4 24 IB0054606 02 A...
Page 140: ...6 SHMEM Description and Configuration SHMEM Benchmark Programs 6 32 IB0054606 02 A...
Page 148: ...8 Dispersive Routing 8 4 IB0054606 02 A...
Page 164: ...9 gPXE HTTP Boot Setup 9 16 IB0054606 02 A...
Page 176: ...A Benchmark Programs Benchmark 3 Messaging Rate Microbenchmarks A 12 IB0054606 02 A...
Page 202: ...B SRP Configuration OFED SRP Configuration B 26 IB0054606 02 A Notes...
Page 206: ...C Integration with a Batch Queuing System Clean up PSM Shared Memory Files C 4 IB0054606 02 A...
Page 238: ...E ULP Troubleshooting Troubleshooting SRP Issues E 20 IB0054606 02 A...
Page 242: ...F Write Combining Verify Write Combining is Working F 4 IB0054606 02 A Notes...
Page 280: ...G Commands and Files Summary of Configuration Files G 38 IB0054606 02 A...
Page 283: ......