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openmpi/README
Samuel Gutierrez 2fb7c344fc Added a new System V (sysv) shared memory component for Open MPI.
Configure Option:
--enable-sysv

MCA Parameter:
mpi_common_sm

mpi_common_sm accepts a comma delimited list of: [sysv],mmap (order
dependent).  The first component that is successfully selected is used. For
example, -mca mpi_common_sm sysv,mmap will first try sysv. If sysv is not
successfully selected, then mmap will be used.  mmap will be used if 
mpi_common_sm is not provided.

Notes:
Please make certain that your system's shmmax limit, or equivalent, is larger
than mpool_sm_min_size.  Otherwise, shmget may fail.

This commit was SVN r23260.
2010-06-09 16:58:52 +00:00

1598 строки
66 KiB
Plaintext

Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
University Research and Technology
Corporation. All rights reserved.
Copyright (c) 2004-2007 The University of Tennessee and The University
of Tennessee Research Foundation. All rights
reserved.
Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
University of Stuttgart. All rights reserved.
Copyright (c) 2004-2007 The Regents of the University of California.
All rights reserved.
Copyright (c) 2006-2010 Cisco Systems, Inc. All rights reserved.
Copyright (c) 2006-2007 Voltaire, Inc. All rights reserved.
Copyright (c) 2006-2008 Sun Microsystems, Inc. All rights reserved.
Copyright (c) 2007 Myricom, Inc. All rights reserved.
Copyright (c) 2008 IBM Corporation. All rights reserved.
$COPYRIGHT$
Additional copyrights may follow
$HEADER$
===========================================================================
When submitting questions and problems, be sure to include as much
extra information as possible. This web page details all the
information that we request in order to provide assistance:
http://www.open-mpi.org/community/help/
The best way to report bugs, send comments, or ask questions is to
sign up on the user's and/or developer's mailing list (for user-level
and developer-level questions; when in doubt, send to the user's
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Because of spam, only subscribers are allowed to post to these lists
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joe@mycomputer.example.com!). Visit these pages to subscribe to the
lists:
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Thanks for your time.
===========================================================================
Much, much more information is also available in the Open MPI FAQ:
http://www.open-mpi.org/faq/
===========================================================================
Detailed Open MPI v1.3 / v1.4 Feature List:
o Open MPI RunTime Environment (ORTE) improvements
- General robustness improvements
- Scalable job launch (we've seen ~16K processes in less than a
minute in a highly-optimized configuration)
- New process mappers
- Support for Platform/LSF environments (v7.0.2 and later)
- More flexible processing of host lists
- new mpirun cmd line options and associated functionality
o Fault-Tolerance Features
- Asynchronous, transparent checkpoint/restart support
- Fully coordinated checkpoint/restart coordination component
- Support for the following checkpoint/restart services:
- blcr: Berkley Lab's Checkpoint/Restart
- self: Application level callbacks
- Support for the following interconnects:
- tcp
- mx
- openib
- sm
- self
- Improved Message Logging
o MPI_THREAD_MULTIPLE support for point-to-point messaging in the
following BTLs (note that only MPI point-to-point messaging API
functions support MPI_THREAD_MULTIPLE; other API functions likely
do not):
- tcp
- sm
- mx
- elan
- self
o Point-to-point Messaging Layer (PML) improvements
- Memory footprint reduction
- Improved latency
- Improved algorithm for multiple communication device
("multi-rail") support
o Numerous Open Fabrics improvements/enhancements
- Added iWARP support (including RDMA CM)
- Memory footprint and performance improvements
- "Bucket" SRQ support for better registered memory utilization
- XRC/ConnectX support
- Message coalescing
- Improved error report mechanism with Asynchronous events
- Automatic Path Migration (APM)
- Improved processor/port binding
- Infrastructure for additional wireup strategies
- mpi_leave_pinned is now enabled by default
o uDAPL BTL enhancements
- Multi-rail support
- Subnet checking
- Interface include/exclude capabilities
o Processor affinity
- Linux processor affinity improvements
- Core/socket <--> process mappings
o Collectives
- Performance improvements
- Support for hierarchical collectives (must be activated
manually; see below)
o Miscellaneous
- MPI 2.1 compliant
- Sparse process groups and communicators
- Support for Cray Compute Node Linux (CNL)
- One-sided RDMA component (BTL-level based rather than PML-level
based)
- Aggregate MCA parameter sets
- MPI handle debugging
- Many small improvements to the MPI C++ bindings
- Valgrind support
- VampirTrace support
- Updated ROMIO to the version from MPICH2 1.0.7
- Removed the mVAPI IB stacks
- Display most error messages only once (vs. once for each
process)
- Many other small improvements and bug fixes, too numerous to
list here
Known issues
------------
o XGrid support is currently broken.
https://svn.open-mpi.org/trac/ompi/ticket/1777
o MPI_REDUCE_SCATTER does not work with counts of 0.
https://svn.open-mpi.org/trac/ompi/ticket/1559
o Processes that were spawned via MPI_COMM_SPAWN[_MULTIPLE] cannot
themselves invoke MPI_COMM_SPAWN[_MULTIPLE]. This has been fixed
in the Open MPI v1.5 series.
o Please also see the Open MPI bug tracker for bugs beyond this release.
https://svn.open-mpi.org/trac/ompi/report
===========================================================================
The following abbreviated list of release notes applies to this code
base as of this writing (28 April 2010):
General notes
-------------
- Open MPI includes support for a wide variety of supplemental
hardware and software package. When configuring Open MPI, you may
need to supply additional flags to the "configure" script in order
to tell Open MPI where the header files, libraries, and any other
required files are located. As such, running "configure" by itself
may not include support for all the devices (etc.) that you expect,
especially if their support headers / libraries are installed in
non-standard locations. Network interconnects are an easy example
to discuss -- Myrinet and OpenFabrics networks, for example, both
have supplemental headers and libraries that must be found before
Open MPI can build support for them. You must specify where these
files are with the appropriate options to configure. See the
listing of configure command-line switches, below, for more details.
- The majority of Open MPI's documentation is here in this file, the
included man pages, and on the web site FAQ
(http://www.open-mpi.org/). This will eventually be supplemented
with cohesive installation and user documentation files.
- Note that Open MPI documentation uses the word "component"
frequently; the word "plugin" is probably more familiar to most
users. As such, end users can probably completely substitute the
word "plugin" wherever you see "component" in our documentation.
For what it's worth, we use the word "component" for historical
reasons, mainly because it is part of our acronyms and internal API
functionc calls.
- The run-time systems that are currently supported are:
- rsh / ssh
- LoadLeveler
- PBS Pro, Open PBS, Torque
- Platform LSF (v7.0.2 and later)
- SLURM
- XGrid (known to be broken in the 1.3 and 1.4 series)
- Cray XT-3 and XT-4
- Sun Grid Engine (SGE) 6.1, 6.2 and open source Grid Engine
- Microsoft Windows CCP (Microsoft Windows server 2003 and 2008)
- Systems that have been tested are:
- Linux (various flavors/distros), 32 bit, with gcc, and Sun Studio 12
- Linux (various flavors/distros), 64 bit (x86), with gcc, Absoft,
Intel, Portland, Pathscale, and Sun Studio 12 compilers (*)
- OS X (10.4), 32 and 64 bit (i386, PPC, PPC64, x86_64), with gcc
and Absoft compilers (*)
- Solaris 10 update 2, 3 and 4, 32 and 64 bit (SPARC, i386, x86_64),
with Sun Studio 10, 11 and 12
(*) Be sure to read the Compiler Notes, below.
- Other systems have been lightly (but not fully tested):
- Other 64 bit platforms (e.g., Linux on PPC64)
- Microsoft Windows CCP (Microsoft Windows server 2003 and 2008);
see the README.WINDOWS file.
Compiler Notes
--------------
- Mixing compilers from different vendors when building Open MPI
(e.g., using the C/C++ compiler from one vendor and the F77/F90
compiler from a different vendor) has been successfully employed by
some Open MPI users (discussed on the Open MPI user's mailing list),
but such configurations are not tested and not documented. For
example, such configurations may require additional compiler /
linker flags to make Open MPI build properly.
- Open MPI does not support the Sparc v8 CPU target, which is the
default on Sun Solaris. The v8plus (32 bit) or v9 (64 bit)
targets must be used to build Open MPI on Solaris. This can be
done by including a flag in CFLAGS, CXXFLAGS, FFLAGS, and FCFLAGS,
-xarch=v8plus for the Sun compilers, -mv8plus for GCC.
- At least some versions of the Intel 8.1 compiler seg fault while
compiling certain Open MPI source code files. As such, it is not
supported.
- The Intel 9.0 v20051201 compiler on IA64 platforms seems to have a
problem with optimizing the ptmalloc2 memory manager component (the
generated code will segv). As such, the ptmalloc2 component will
automatically disable itself if it detects that it is on this
platform/compiler combination. The only effect that this should
have is that the MCA parameter mpi_leave_pinned will be inoperative.
- Early versions of the Portland Group 6.0 compiler have problems
creating the C++ MPI bindings as a shared library (e.g., v6.0-1).
Tests with later versions show that this has been fixed (e.g.,
v6.0-5).
- The Portland Group compilers prior to version 7.0 require the
"-Msignextend" compiler flag to extend the sign bit when converting
from a shorter to longer integer. This is is different than other
compilers (such as GNU). When compiling Open MPI with the Portland
compiler suite, the following flags should be passed to Open MPI's
configure script:
shell$ ./configure CFLAGS=-Msignextend CXXFLAGS=-Msignextend \
--with-wrapper-cflags=-Msignextend \
--with-wrapper-cxxflags=-Msignextend ...
This will both compile Open MPI with the proper compile flags and
also automatically add "-Msignextend" when the C and C++ MPI wrapper
compilers are used to compile user MPI applications.
- Using the MPI C++ bindings with the Pathscale compiler is known
to fail, possibly due to Pathscale compiler issues.
- Using the Absoft compiler to build the MPI Fortran bindings on Suse
9.3 is known to fail due to a Libtool compatibility issue.
- Open MPI will build bindings suitable for all common forms of
Fortran 77 compiler symbol mangling on platforms that support it
(e.g., Linux). On platforms that do not support weak symbols (e.g.,
OS X), Open MPI will build Fortran 77 bindings just for the compiler
that Open MPI was configured with.
Hence, on platforms that support it, if you configure Open MPI with
a Fortran 77 compiler that uses one symbol mangling scheme, you can
successfully compile and link MPI Fortran 77 applications with a
Fortran 77 compiler that uses a different symbol mangling scheme.
NOTE: For platforms that support the multi-Fortran-compiler bindings
(i.e., weak symbols are supported), due to limitations in the MPI
standard and in Fortran compilers, it is not possible to hide these
differences in all cases. Specifically, the following two cases may
not be portable between different Fortran compilers:
1. The C constants MPI_F_STATUS_IGNORE and MPI_F_STATUSES_IGNORE
will only compare properly to Fortran applications that were
created with Fortran compilers that that use the same
name-mangling scheme as the Fortran compiler that Open MPI was
configured with.
2. Fortran compilers may have different values for the logical
.TRUE. constant. As such, any MPI function that uses the Fortran
LOGICAL type may only get .TRUE. values back that correspond to
the the .TRUE. value of the Fortran compiler that Open MPI was
configured with. Note that some Fortran compilers allow forcing
.TRUE. to be 1 and .FALSE. to be 0. For example, the Portland
Group compilers provide the "-Munixlogical" option, and Intel
compilers (version >= 8.) provide the "-fpscomp logicals" option.
You can use the ompi_info command to see the Fortran compiler that
Open MPI was configured with.
- The Fortran 90 MPI bindings can now be built in one of three sizes
using --with-mpi-f90-size=SIZE (see description below). These sizes
reflect the number of MPI functions included in the "mpi" Fortran 90
module and therefore which functions will be subject to strict type
checking. All functions not included in the Fortran 90 module can
still be invoked from F90 applications, but will fall back to
Fortran-77 style checking (i.e., little/none).
- trivial: Only includes F90-specific functions from MPI-2. This
means overloaded versions of MPI_SIZEOF for all the MPI-supported
F90 intrinsic types.
- small (default): All the functions in "trivial" plus all MPI
functions that take no choice buffers (meaning buffers that are
specified by the user and are of type (void*) in the C bindings --
generally buffers specified for message passing). Hence,
functions like MPI_COMM_RANK are included, but functions like
MPI_SEND are not.
- medium: All the functions in "small" plus all MPI functions that
take one choice buffer (e.g., MPI_SEND, MPI_RECV, ...). All
one-choice-buffer functions have overloaded variants for each of
the MPI-supported Fortran intrinsic types up to the number of
dimensions specified by --with-f90-max-array-dim (default value is
4).
Increasing the size of the F90 module (in order from trivial, small,
and medium) will generally increase the length of time required to
compile user MPI applications. Specifically, "trivial"- and
"small"-sized F90 modules generally allow user MPI applications to
be compiled fairly quickly but lose type safety for all MPI
functions with choice buffers. "medium"-sized F90 modules generally
take longer to compile user applications but provide greater type
safety for MPI functions.
Note that MPI functions with two choice buffers (e.g., MPI_GATHER)
are not currently included in Open MPI's F90 interface. Calls to
these functions will automatically fall through to Open MPI's F77
interface. A "large" size that includes the two choice buffer MPI
functions is possible in future versions of Open MPI.
General Run-Time Support Notes
------------------------------
- The Open MPI installation must be in your PATH on all nodes (and
potentially LD_LIBRARY_PATH, if libmpi is a shared library), unless
using the --prefix or --enable-mpirun-prefix-by-default
functionality (see below).
- LAM/MPI-like mpirun notation of "C" and "N" is not yet supported.
- The XGrid support is experimental - see the Open MPI FAQ and this
post on the Open MPI user's mailing list for more information:
http://www.open-mpi.org/community/lists/users/2006/01/0539.php
*** NOTE: Open MPI's XGrid support is known to be broken in the 1.3
and 1.4 series. Are you an OS X developer? We'd love to have
someone join us to fix this stuff.
- Open MPI's run-time behavior can be customized via MCA ("MPI
Component Architecture") parameters (see below for more information
on how to get/set MCA parameter values). Some MCA parameters can be
set in a way that renders Open MPI inoperable (see notes about MCA
parameters later in this file). In particular, some parameters have
required options that must be included.
- If specified, the "btl" parameter must include the "self"
component, or Open MPI will not be able to deliver messages to the
same rank as the sender. For example: "mpirun --mca btl tcp,self
..."
- If specified, the "btl_tcp_if_exclude" paramater must include the
loopback device ("lo" on many Linux platforms), or Open MPI will
not be able to route MPI messages using the TCP BTL. For example:
"mpirun --mca btl_tcp_if_exclude lo,eth1 ..."
- Running on nodes with different endian and/or different datatype
sizes within a single parallel job is supported in this release.
However, Open MPI does not resize data when datatypes differ in size
(for example, sending a 4 byte MPI_DOUBLE and receiving an 8 byte
MPI_DOUBLE will fail).
MPI Functionality and Features
------------------------------
- All MPI-2.1 functionality is supported.
- MPI_THREAD_MULTIPLE support is included, but is only lightly tested.
It likely does not work for thread-intensive applications. Note
that *only* the MPI point-to-point communication functions for the
BTL's listed above are considered thread safe. Other support
functions (e.g., MPI attributes) have not been certified as safe
when simultaneously used by multiple threads.
Note that Open MPI's thread support is in a fairly early stage; the
above devices are likely to *work*, but the latency is likely to be
fairly high. Specifically, efforts so far have concentrated on
*correctness*, not *performance* (yet).
- MPI_REAL16 and MPI_COMPLEX32 are only supported on platforms where a
portable C datatype can be found that matches the Fortran type
REAL*16, both in size and bit representation.
Collectives
-----------
- The "hierarch" coll component (i.e., an implementation of MPI
collective operations) attempts to discover network layers of
latency in order to segregate individual "local" and "global"
operations as part of the overall collective operation. In this
way, network traffic can be reduced -- or possibly even minimized
(similar to MagPIe). The current "hierarch" component only
separates MPI processes into on- and off-node groups.
Hierarch has had sufficient correctness testing, but has not
received much performance tuning. As such, hierarch is not
activated by default -- it must be enabled manually by setting its
priority level to 100:
mpirun --mca coll_hierarch_priority 100 ...
We would appreciate feedback from the user community about how well
hierarch works for your applications.
Network Support
---------------
- The OpenFabrics Enterprise Distribution (OFED) software package v1.0
will not work properly with Open MPI v1.2 (and later) due to how its
Mellanox InfiniBand plugin driver is created. The problem is fixed
OFED v1.1 (and later).
- Older mVAPI-based InfiniBand drivers (Mellanox VAPI) are no longer
supported. Please use an older version of Open MPI (1.2 series or
earlier) if you need mVAPI support.
- The use of fork() with the openib BTL is only partially supported,
and only on Linux kernels >= v2.6.15 with libibverbs v1.1 or later
(first released as part of OFED v1.2), per restrictions imposed by
the OFED network stack.
- There are three MPI network models available: "ob1", "csum", and
"cm". "ob1" and "csum" use BTL ("Byte Transfer Layer") components
for each supported network. "cm" uses MTL ("Matching Tranport
Layer") components for each supported network.
- "ob1" supports a variety of networks that can be used in
combination with each other (per OS constraints; e.g., there are
reports that the GM and OpenFabrics kernel drivers do not operate
well together):
- OpenFabrics: InfiniBand and iWARP
- Loopback (send-to-self)
- Myrinet: GM and MX (including Open-MX)
- Portals
- Quadrics Elan
- Shared memory
- TCP
- SCTP
- uDAPL
- "csum" is exactly the same as "ob1", except that it performs
additional data integrity checks to ensure that the received data
is intact (vs. trusting the underlying network to deliver the data
correctly). csum supports all the same networks as ob1, but there
is a performance penalty for the additional integrity checks.
- "cm" supports a smaller number of networks (and they cannot be
used together), but may provide better better overall MPI
performance:
- Myrinet MX (including Open-MX, but not GM)
- InfiniPath PSM
- Portals
Open MPI will, by default, choose to use "cm" when the InfiniPath
PSM MTL can be used. Otherwise, "ob1" will be used and the
corresponding BTLs will be selected. "csum" will never be selected
by default. Users can force the use of ob1 or cm if desired by
setting the "pml" MCA parameter at run-time:
shell$ mpirun --mca pml ob1 ...
or
shell$ mpirun --mca pml csum ...
or
shell$ mpirun --mca pml cm ...
- Myrinet MX (and Open-MX) support is shared between the 2 internal
devices, the MTL and the BTL. The design of the BTL interface in
Open MPI assumes that only naive one-sided communication
capabilities are provided by the low level communication layers.
However, modern communication layers such as Myrinet MX, InfiniPath
PSM, or Portals, natively implement highly-optimized two-sided
communication semantics. To leverage these capabilities, Open MPI
provides the "cm" PML and corresponding MTL components to transfer
messages rather than bytes. The MTL interface implements a shorter
code path and lets the low-level network library decide which
protocol to use (depending on issues such as message length,
internal resources and other parameters specific to the underlying
interconnect). However, Open MPI cannot currently use multiple MTL
modules at once. In the case of the MX MTL, process loopback and
on-node shared memory communications are provided by the MX library.
Moreover, the current MX MTL does not support message pipelining
resulting in lower performances in case of non-contiguous
data-types.
The "ob1" and "csum" PMLs and BTL components use Open MPI's internal
on-node shared memory and process loopback devices for high
performance. The BTL interface allows multiple devices to be used
simultaneously. For the MX BTL it is recommended that the first
segment (which is as a threshold between the eager and the
rendezvous protocol) should always be at most 4KB, but there is no
further restriction on the size of subsequent fragments.
The MX MTL is recommended in the common case for best performance on
10G hardware when most of the data transfers cover contiguous memory
layouts. The MX BTL is recommended in all other cases, such as when
using multiple interconnects at the same time (including TCP), or
transferring non contiguous data-types.
- Linux "knem" support is used when the "sm" (shared memory) BTL is
compiled with knem support (see the --with-knem configure option)
and the knem Linux module is loaded in the running kernel. If the
knem Linux kernel module is not loaded, the knem support is (by
default) silently deactivated during Open MPI jobs.
See http://runtime.bordeaux.inria.fr/knem/ for details on Knem.
===========================================================================
Building Open MPI
-----------------
Open MPI uses a traditional configure script paired with "make" to
build. Typical installs can be of the pattern:
---------------------------------------------------------------------------
shell$ ./configure [...options...]
shell$ make all install
---------------------------------------------------------------------------
There are many available configure options (see "./configure --help"
for a full list); a summary of the more commonly used ones follows:
--prefix=<directory>
Install Open MPI into the base directory named <directory>. Hence,
Open MPI will place its executables in <directory>/bin, its header
files in <directory>/include, its libraries in <directory>/lib, etc.
--with-elan=<directory>
Specify the directory where the Quadrics Elan library and header
files are located. This option is generally only necessary if the
Elan headers and libraries are not in default compiler/linker
search paths.
Elan is the support library for Quadrics-based networks.
--with-elan-libdir=<directory>
Look in directory for the Quadrics Elan libraries. By default, Open
MPI will look in <elan directory>/lib and <elan directory>/lib64,
which covers most cases. This option is only needed for special
configurations.
--with-gm=<directory>
Specify the directory where the GM libraries and header files are
located. This option is generally only necessary if the GM headers
and libraries are not in default compiler/linker search paths.
GM is the support library for older Myrinet-based networks (GM has
been obsoleted by MX).
--with-gm-libdir=<directory>
Look in directory for the GM libraries. By default, Open MPI will
look in <gm directory>/lib and <gm directory>/lib64, which covers
most cases. This option is only needed for special configurations.
--with-hwloc=<location>
Build hwloc support. If <location> is "internal", Open MPI's
internal copy of hwloc is used. If <location> is "external", Open
MPI will search in default locations for an hwloc installation.
Finally, if <location> is a directory, that directory will be
searched for a valid hwloc installation, just like other
--with-FOO=<directory> configure options.
hwloc is a support library that provides processor and memory
affinity information for NUMA platforms.
--with-hwloc-libdir=<directory>
Look in directory for the hwloc libraries. This option is only
usable when building Open MPI against an external hwloc
installation. Just like other --with-FOO-libdir configure options,
this option is only needed for special configurations.
--with-knem=<directory>
Specify the directory where the knem libraries and header files are
located. This option is generally only necessary if the kenm headers
and libraries are not in default compiler/linker search paths.
kenm is a Linux kernel module that allows direct process-to-process
memory copies (optionally using hardware offload), potentially
increasing bandwidth for large messages sent between messages on the
same server. See http://runtime.bordeaux.inria.fr/knem/ for
details.
--with-mx=<directory>
Specify the directory where the MX libraries and header files are
located. This option is generally only necessary if the MX headers
and libraries are not in default compiler/linker search paths.
MX is the support library for Myrinet-based networks. An open
source software package named Open-MX provides the same
functionality on Ethernet-based clusters (Open-MX can provide
MPI performance improvements compared to TCP messaging).
--with-mx-libdir=<directory>
Look in directory for the MX libraries. By default, Open MPI will
look in <mx directory>/lib and <mx directory>/lib64, which covers
most cases. This option is only needed for special configurations.
--with-openib=<directory>
Specify the directory where the OpenFabrics (previously known as
OpenIB) libraries and header files are located. This option is
generally only necessary if the OpenFabrics headers and libraries
are not in default compiler/linker search paths.
"OpenFabrics" refers to iWARP- and InifiniBand-based networks.
--with-openib-libdir=<directory>
Look in directory for the OpenFabrics libraries. By default, Open
MPI will look in <openib directory>/lib and <openib
directory>/lib64, which covers most cases. This option is only
needed for special configurations.
--with-portals=<directory>
Specify the directory where the Portals libraries and header files
are located. This option is generally only necessary if the Portals
headers and libraries are not in default compiler/linker search
paths.
Portals is the support library for Cray interconnects, but is also
available on other platforms (e.g., there is a Portals library
implemented over regular TCP).
--with-portals-config=<type>
Configuration to use for Portals support. The following <type>
values are possible: "utcp", "xt3", "xt3-modex" (default: utcp).
--with-portals-libs=<libs>
Additional libraries to link with for Portals support.
--with-psm=<directory>
Specify the directory where the QLogic InfiniPath PSM library and
header files are located. This option is generally only necessary
if the InfiniPath headers and libraries are not in default
compiler/linker search paths.
PSM is the support library for QLogic InfiniPath network adapters.
--with-psm-libdir=<directory>
Look in directory for the PSM libraries. By default, Open MPI will
look in <psm directory>/lib and <psm directory>/lib64, which covers
most cases. This option is only needed for special configurations.
--with-sctp=<directory>
Specify the directory where the SCTP libraries and header files are
located. This option is generally only necessary if the SCTP headers
and libraries are not in default compiler/linker search paths.
SCTP is a special network stack over ethernet networks.
--with-sctp-libdir=<directory>
Look in directory for the SCTP libraries. By default, Open MPI will
look in <sctp directory>/lib and <sctp directory>/lib64, which covers
most cases. This option is only needed for special configurations.
--with-udapl=<directory>
Specify the directory where the UDAPL libraries and header files are
located. Note that UDAPL support is disabled by default on Linux;
the --with-udapl flag must be specified in order to enable it.
Specifying the directory argument is generally only necessary if the
UDAPL headers and libraries are not in default compiler/linker
search paths.
UDAPL is the support library for high performance networks in Sun
HPC ClusterTools and on Linux OpenFabrics networks (although the
"openib" options are preferred for Linux OpenFabrics networks, not
UDAPL).
--with-udapl-libdir=<directory>
Look in directory for the UDAPL libraries. By default, Open MPI
will look in <udapl directory>/lib and <udapl directory>/lib64,
which covers most cases. This option is only needed for special
configurations.
--with-lsf=<directory>
Specify the directory where the LSF libraries and header files are
located. This option is generally only necessary if the LSF headers
and libraries are not in default compiler/linker search paths.
LSF is a resource manager system, frequently used as a batch
scheduler in HPC systems.
NOTE: If you are using LSF version 7.0.5, you will need to add
"LIBS=-ldl" to the configure command line. For example:
./configure LIBS=-ldl --with-lsf ...
This workaround should *only* be needed for LSF 7.0.5.
--with-lsf-libdir=<directory>
Look in directory for the LSF libraries. By default, Open MPI will
look in <lsf directory>/lib and <lsf directory>/lib64, which covers
most cases. This option is only needed for special configurations.
--with-tm=<directory>
Specify the directory where the TM libraries and header files are
located. This option is generally only necessary if the TM headers
and libraries are not in default compiler/linker search paths.
TM is the support library for the Torque and PBS Pro resource
manager systems, both of which are frequently used as a batch
scheduler in HPC systems.
--with-sge
Specify to build support for the Sun Grid Engine (SGE) resource
manager. SGE support is disabled by default; this option must be
specified to build OMPI's SGE support.
The Sun Grid Engine (SGE) is a resource manager system, frequently
used as a batch scheduler in HPC systems.
--with-esmtp=<directory>
Specify the directory where the libESMTP libraries and header files are
located. This option is generally only necessary of the libESMTP
headers and libraries are not included in the default
compiler/linker search paths.
libESMTP is a support library for sending e-mail.
--with-mpi-param_check(=value)
"value" can be one of: always, never, runtime. If --with-mpi-param
is not specified, "runtime" is the default. If --with-mpi-param
is specified with no value, "always" is used. Using
--without-mpi-param-check is equivalent to "never".
- always: the parameters of MPI functions are always checked for
errors
- never: the parameters of MPI functions are never checked for
errors
- runtime: whether the parameters of MPI functions are checked
depends on the value of the MCA parameter mpi_param_check
(default: yes).
--with-threads=value
Since thread support is only partially tested, it is disabled by
default. To enable threading, use "--with-threads=posix". This is
most useful when combined with --enable-mpi-thread-multiple.
--enable-mpi-thread-multiple
Allows the MPI thread level MPI_THREAD_MULTIPLE. See
--with-threads; this is currently disabled by default. Enabling
this feature will automatically --enable-opal-multi-threads.
--enable-opal-multi-threads
Enables thread lock support in the OPAL and ORTE layers. Does
not enable MPI_THREAD_MULTIPLE - see above option for that feature.
This is currently disabled by default.
--disable-mpi-cxx
Disable building the C++ MPI bindings. Note that this does *not*
disable the C++ checks during configure; some of Open MPI's tools
are written in C++ and therefore require a C++ compiler to be built.
--disable-mpi-cxx-seek
Disable the MPI::SEEK_* constants. Due to a problem with the MPI-2
specification, these constants can conflict with system-level SEEK_*
constants. Open MPI attempts to work around this problem, but the
workaround may fail in some esoteric situations. The
--disable-mpi-cxx-seek switch disables Open MPI's workarounds (and
therefore the MPI::SEEK_* constants will be unavailable).
--disable-mpi-f77
Disable building the Fortran 77 MPI bindings.
--disable-mpi-f90
Disable building the Fortran 90 MPI bindings. Also related to the
--with-f90-max-array-dim and --with-mpi-f90-size options.
--with-mpi-f90-size=<SIZE>
Three sizes of the MPI F90 module can be built: trivial (only a
handful of MPI-2 F90-specific functions are included in the F90
module), small (trivial + all MPI functions that take no choice
buffers), and medium (small + all MPI functions that take 1 choice
buffer). This parameter is only used if the F90 bindings are
enabled.
--with-f90-max-array-dim=<DIM>
The F90 MPI bindings are strictly typed, even including the number of
dimensions for arrays for MPI choice buffer parameters. Open MPI
generates these bindings at compile time with a maximum number of
dimensions as specified by this parameter. The default value is 4.
--enable-mpi-ext(=<list>)
Enable Open MPI's non-portable API extensions. If no <list> is
specified, all of the extensions are enabled.
See "Open MPI API Extensions", below, for more details.
--enable-mpirun-prefix-by-default
This option forces the "mpirun" command to always behave as if
"--prefix $prefix" was present on the command line (where $prefix is
the value given to the --prefix option to configure). This prevents
most rsh/ssh-based users from needing to modify their shell startup
files to set the PATH and/or LD_LIBRARY_PATH for Open MPI on remote
nodes. Note, however, that such users may still desire to set PATH
-- perhaps even in their shell startup files -- so that executables
such as mpicc and mpirun can be found without needing to type long
path names. --enable-orterun-prefix-by-default is a synonym for
this option.
--disable-shared
By default, libmpi is built as a shared library, and all components
are built as dynamic shared objects (DSOs). This switch disables
this default; it is really only useful when used with
--enable-static. Specifically, this option does *not* imply
--enable-static; enabling static libraries and disabling shared
libraries are two independent options.
--enable-static
Build libmpi as a static library, and statically link in all
components. Note that this option does *not* imply
--disable-shared; enabling static libraries and disabling shared
libraries are two independent options.
--enable-sparse-groups
Enable the usage of sparse groups. This would save memory
significantly especially if you are creating large
communicators. (Disabled by default)
--enable-peruse
Enable the PERUSE MPI data analysis interface.
--enable-dlopen
Build all of Open MPI's components as standalone Dynamic Shared
Objects (DSO's) that are loaded at run-time. The opposite of this
option, --disable-dlopen, causes two things:
1. All of Open MPI's components will be built as part of Open MPI's
normal libraries (e.g., libmpi).
2. Open MPI will not attempt to open any DSO's at run-time.
Note that this option does *not* imply that OMPI's libraries will be
built as static objects (e.g., libmpi.a). It only specifies the
location of OMPI's components: standalone DSOs or folded into the
Open MPI libraries. You can control whenther Open MPI's libraries
are build as static or dynamic via --enable|disable-static and
--enable|disable-shared.
--with-libltdl[=VALUE]
This option specifies where to find the GNU Libtool libltdl support
library. The following VALUEs are permitted:
internal: Use Open MPI's internal copy of libltdl.
external: Use an external libltdl installation (rely on default
compiler and linker paths to find it)
<no value>: Same as "internal".
<directory>: Specify the localtion of a specific libltdl
installation to use
By default (or if --with-libltdl is specified with no VALUE), Open
MPI will build and use the copy of libltdl that it has in its source
tree. However, if the VALUE is "external", Open MPI will look for
the relevant libltdl header file and library in default compiler /
linker locations. Or, VALUE can be a directory tree where the
libltdl header file can library can be found. This option allows
operating systems to include Open MPI and use their default libltdl
installation instead of Open MPI's bundled libltdl.
Note that this option is ignored if --disable-dlopen is specified.
--enable-heterogeneous
Enable support for running on heterogeneous clusters (e.g., machines
with different endian representations). Heterogeneous support is
disabled by default because it imposes a minor performance penalty.
--enable-sysv
Enable System V (sysv) shared memory support. By default, System V
shared memory support is disabled.
--with-wrapper-cflags=<cflags>
--with-wrapper-cxxflags=<cxxflags>
--with-wrapper-fflags=<fflags>
--with-wrapper-fcflags=<fcflags>
--with-wrapper-ldflags=<ldflags>
--with-wrapper-libs=<libs>
Add the specified flags to the default flags that used are in Open
MPI's "wrapper" compilers (e.g., mpicc -- see below for more
information about Open MPI's wrapper compilers). By default, Open
MPI's wrapper compilers use the same compilers used to build Open
MPI and specify an absolute minimum set of additional flags that are
necessary to compile/link MPI applications. These configure options
give system administrators the ability to embed additional flags in
OMPI's wrapper compilers (which is a local policy decision). The
meanings of the different flags are:
<cflags>: Flags passed by the mpicc wrapper to the C compiler
<cxxflags>: Flags passed by the mpic++ wrapper to the C++ compiler
<fflags>: Flags passed by the mpif77 wrapper to the F77 compiler
<fcflags>: Flags passed by the mpif90 wrapper to the F90 compiler
<ldflags>: Flags passed by all the wrappers to the linker
<libs>: Flags passed by all the wrappers to the linker
There are other ways to configure Open MPI's wrapper compiler
behavior; see the Open MPI FAQ for more information.
There are many other options available -- see "./configure --help".
Changing the compilers that Open MPI uses to build itself uses the
standard Autoconf mechanism of setting special environment variables
either before invoking configure or on the configure command line.
The following environment variables are recognized by configure:
CC - C compiler to use
CFLAGS - Compile flags to pass to the C compiler
CPPFLAGS - Preprocessor flags to pass to the C compiler
CXX - C++ compiler to use
CXXFLAGS - Compile flags to pass to the C++ compiler
CXXCPPFLAGS - Preprocessor flags to pass to the C++ compiler
F77 - Fortran 77 compiler to use
FFLAGS - Compile flags to pass to the Fortran 77 compiler
FC - Fortran 90 compiler to use
FCFLAGS - Compile flags to pass to the Fortran 90 compiler
LDFLAGS - Linker flags to pass to all compilers
LIBS - Libraries to pass to all compilers (it is rarely
necessary for users to need to specify additional LIBS)
For example:
shell$ ./configure CC=mycc CXX=myc++ F77=myf77 F90=myf90 ...
***Note: We generally suggest using the above command line form for
setting different compilers (vs. setting environment variables and
then invoking "./configure"). The above form will save all
variables and values in the config.log file, which makes
post-mortem analysis easier when problems occur.
Note that you may also want to ensure that the value of
LD_LIBRARY_PATH is set appropriately (or not at all) for your build
(or whatever environment variable is relevant for your operating
system). For example, some users have been tripped up by setting to
use non-default Fortran compilers via FC / F77, but then failing to
set LD_LIBRARY_PATH to include the directory containing that
non-default Fortran compiler's support libraries. This causes Open
MPI's configure script to fail when it tries to compile / link / run
simple Fortran programs.
It is required that the compilers specified be compile and link
compatible, meaning that object files created by one compiler must be
able to be linked with object files from the other compilers and
produce correctly functioning executables.
Open MPI supports all the "make" targets that are provided by GNU
Automake, such as:
all - build the entire Open MPI package
install - install Open MPI
uninstall - remove all traces of Open MPI from the $prefix
clean - clean out the build tree
Once Open MPI has been built and installed, it is safe to run "make
clean" and/or remove the entire build tree.
VPATH and parallel builds are fully supported.
Generally speaking, the only thing that users need to do to use Open
MPI is ensure that <prefix>/bin is in their PATH and <prefix>/lib is
in their LD_LIBRARY_PATH. Users may need to ensure to set the PATH
and LD_LIBRARY_PATH in their shell setup files (e.g., .bashrc, .cshrc)
so that non-interactive rsh/ssh-based logins will be able to find the
Open MPI executables.
===========================================================================
Open MPI Version Numbers and Binary Compatibility
-------------------------------------------------
Open MPI has two sets of version numbers that are likely of interest
to end users / system administrator:
* Software version number
* Shared library version numbers
Both are described below, followed by a discussion of application
binary interface (ABI) compatibility implications.
Software Version Number
-----------------------
Open MPI's version numbers are the union of several different values:
major, minor, release, and an optional quantifier.
* Major: The major number is the first integer in the version string
(e.g., v1.2.3). Changes in the major number typically indicate a
significant change in the code base and/or end-user
functionality. The major number is always included in the version
number.
* Minor: The minor number is the second integer in the version
string (e.g., v1.2.3). Changes in the minor number typically
indicate a incremental change in the code base and/or end-user
functionality. The minor number is always included in the version
number. Starting with Open MPI v1.3.0, the minor release number
took on additional significance (see this wiki page for more
details):
o Even minor release numbers are part of "super-stable"
release series (e.g., v1.4.0). Releases in super stable series
are well-tested, time-tested, and mature. Such releases are
recomended for production sites. Changes between subsequent
releases in super stable series are expected to be fairly small.
o Odd minor release numbers are part of "feature" release
series (e.g., 1.3.7). Releases in feature releases are
well-tested, but they are not necessarily time-tested or as
mature as super stable releases. Changes between subsequent
releases in feature series may be large.
* Release: The release number is the third integer in the version
string (e.g., v1.2.3). Changes in the release number typically
indicate a bug fix in the code base and/or end-user
functionality. If the release number is 0, it is omitted from the
version number (e.g., v1.2 has a release number of 0).
* Quantifier: Open MPI version numbers sometimes have an arbitrary
string affixed to the end of the version number. Common strings
include:
o aX: Indicates an alpha release. X is an integer indicating
the number of the alpha release (e.g., v1.2.3a5 indicates the
5th alpha release of version 1.2.3).
o bX: Indicates a beta release. X is an integer indicating
the number of the beta release (e.g., v1.2.3b3 indicates the 3rd
beta release of version 1.2.3).
o rcX: Indicates a release candidate. X is an integer
indicating the number of the release candidate (e.g., v1.2.3rc4
indicates the 4th release candidate of version 1.2.3).
o rV or hgV: Indicates the Subversion / Mercurial repository
number string that the release was made from (V is usually an
integer for Subversion releases and usually a string for
Mercurial releases). Although all official Open MPI releases are
tied to a single, specific Subversion or Mercurial repository
number (which can be obtained from the ompi_info command), only
some releases have the Subversion / Mercurial repository number
in the version number. Development snapshot tarballs, for
example, have the Subversion repository included in the version
to reflect that they are a development snapshot of an upcoming
release (e.g., v1.2.3r1234 indicates a development snapshot of
version 1.2.3 corresponding to Subversion repository number
1234).
Quantifiers may be mixed together -- for example v1.2.3rc7r2345
indicates a development snapshot of an upcoming 7th release
candidate for version 1.2.3 corresponding to Subversion repository
number 2345.
Shared Library Version Number
-----------------------------
Open MPI started using the GNU Libtool shared library versioning
scheme with the release of v1.3.2.
NOTE: Only official releases of Open MPI adhere to this versioning
scheme. "Beta" releases, release candidates, and nightly
tarballs, developer snapshots, and Subversion/Mercurial snapshot
tarballs likely will all have arbitrary/meaningless shared
library version numbers.
For deep voodoo technical reasons, only the MPI API libraries were
versioned until Open MPI v1.5 was released (i.e., libmpi*so --
libopen-rte.so or libopen-pal.so were not versioned until v1.5).
Please see https://svn.open-mpi.org/trac/ompi/ticket/2092 for more
details.
NOTE: This policy change will cause an ABI incompatibility between MPI
applications compiled/linked against the Open MPI v1.4 series;
such applications will not be able to upgrade to the Open MPI
v1.5 series without re-linking. Sorry folks!
The GNU Libtool official documentation details how the versioning
scheme works. The quick version is that the shared library versions
are a triple of integers: (current,revision,age), or "c:r:a". This
triple is not related to the Open MPI software version number. There
are six simple rules for updating the values (taken almost verbatim
from the Libtool docs):
1. Start with version information of "0:0:0" for each shared library.
2. Update the version information only immediately before a public
release of your software. More frequent updates are unnecessary,
and only guarantee that the current interface number gets larger
faster.
3. If the library source code has changed at all since the last
update, then increment revision ("c:r:a" becomes "c:r+1:a").
4. If any interfaces have been added, removed, or changed since the
last update, increment current, and set revision to 0.
5. If any interfaces have been added since the last public release,
then increment age.
6. If any interfaces have been removed since the last public release,
then set age to 0.
Here's how we apply those rules specifically to Open MPI:
1. The above rules do not apply to MCA components (a.k.a. "plugins");
MCA component .so versions stay unspecified.
2. The above rules apply exactly as written to the following
libraries starting with Open MPI version v1.5 (prior to v1.5,
libopen-pal and libopen-rte were still at 0:0:0 for reasons
discussed in bug ticket #2092
https://svn.open-mpi.org/trac/ompi/ticket/2092):
* libopen-rte
* libopen-pal
* libmca_common_*
3. The following libraries use a slightly modified version of the
above rules: rules 4, 5, and 6 only apply to the official MPI
interfaces (functions, global variables). The rationale for this
decision is that the vast majority of our users only care about
the official/public MPI interfaces; we therefore want the .so
version number to reflect only changes to the official MPI API.
Put simply: non-MPI API / internal changes to the
MPI-application-facing libraries are irrelevant to pure MPI
applications.
* libmpi
* libmpi_f77
* libmpi_f90
* libmpi_cxx
4. Note, however, that libmpi.so can have its "revision" number
incremented if libopen-rte or libopen-pal change (because these
two libraries are wholly included in libmpi.so). Specifically:
the revision will change, but since we have defined that the only
relevant API interface in libmpi.so is the official MPI API,
updates to libopen-rte and libopen-pal do not change the "current"
or "age" numbers of libmpi.so.
Application Binary Interface (ABI) Compatibility
------------------------------------------------
Open MPI provided forward application binary interface (ABI)
compatibility for MPI applications starting with v1.3.2. Prior to
that version, no ABI guarantees were provided.
NOTE: Prior to v1.3.2, subtle and strange failures are almost
guaranteed to occur if applications were compiled and linked
against shared libraries from one version of Open MPI and then
run with another. The Open MPI team strongly discourages making
any ABI assumptions before v1.3.2.
Starting with v1.3.2, Open MPI provides forward ABI compatibility in
all versions of a given feature release series and its corresponding
super stable series. For example, on a single platform, an MPI
application linked against Open MPI v1.3.2 shared libraries can be
updated to point to the shared libraries in any successive v1.3.x or
v1.4 release and still work properly (e.g., via the LD_LIBRARY_PATH
environment variable or other operating system mechanism).
Open MPI reserves the right to break ABI compatibility at new feature
release series. For example, the same MPI application from above
(linked against Open MPI v1.3.2 shared libraries) will *not* work with
Open MPI v1.5 shared libraries.
===========================================================================
Checking Your Open MPI Installation
-----------------------------------
The "ompi_info" command can be used to check the status of your Open
MPI installation (located in <prefix>/bin/ompi_info). Running it with
no arguments provides a summary of information about your Open MPI
installation.
Note that the ompi_info command is extremely helpful in determining
which components are installed as well as listing all the run-time
settable parameters that are available in each component (as well as
their default values).
The following options may be helpful:
--all Show a *lot* of information about your Open MPI
installation.
--parsable Display all the information in an easily
grep/cut/awk/sed-able format.
--param <framework> <component>
A <framework> of "all" and a <component> of "all" will
show all parameters to all components. Otherwise, the
parameters of all the components in a specific framework,
or just the parameters of a specific component can be
displayed by using an appropriate <framework> and/or
<component> name.
Changing the values of these parameters is explained in the "The
Modular Component Architecture (MCA)" section, below.
===========================================================================
Open MPI API Extensions
-----------------------
Open MPI contains a framework for extending the MPI API that is
available to applications. Each extension is usually a standalone set of
functionality that is distinct from other extensions (similar to how
Open MPI's plugins are usually unrelated to each other). These
extensions provide new functions and/or constants that are available
to MPI applications.
WARNING: These extensions are neither standard nor portable to other
MPI implementations!
Compiling the extensions
------------------------
Open MPI extensions are not enabled by default; they must be enabled
by Open MPI's configure script. The --enable-mpi-ext command line
switch accepts a comma-delimited list of extensions to enable, or, if
it is specified without a list, all extensions are enabled.
Since extensions are meant to be used by advanced users only, this
file does not document which extensions are available or what they
do. Look in the ompi/mpiext/ directory to see the extensions; each
subdirectory of that directory contains an extension. Each has a
README file that describes what it does.
Using the extensions
--------------------
To reinforce the fact that these extensions are non-standard, you must
include a separate header file after <mpi.h> to obtain the function
prototypes, constant declarations, etc. For example:
#include <mpi.h>
#if defined(OPEN_MPI) && OPEN_MPI
#include <mpi-ext.h>
#endif
int main() {
MPI_Init(NULL, NULL);
#if defined(OPEN_MPI) && OPEN_MPI
{
char ompi_bound[OMPI_AFFINITY_STRING_MAX];
char current_binding[OMPI_AFFINITY_STRING_MAX];
char exists[OMPI_AFFINITY_STRING_MAX];
OMPI_Affinity_str(ompi_bound, current_bindings, exists);
}
#endif
MPI_Finalize();
return 0;
}
Notice that the Open MPI-specific code is surrounded by the #if
statement to ensure that it is only ever compiled by Open MPI.
The Open MPI wrapper compilers (mpicc and friends) should
automatically insert all relevant compiler and linker flags necessary
to use the extensions. No special flags or steps should be necessary
compared to "normal" MPI applications.
===========================================================================
Compiling Open MPI Applications
-------------------------------
Open MPI provides "wrapper" compilers that should be used for
compiling MPI applications:
C: mpicc
C++: mpiCC (or mpic++ if your filesystem is case-insensitive)
Fortran 77: mpif77
Fortran 90: mpif90
For example:
shell$ mpicc hello_world_mpi.c -o hello_world_mpi -g
shell$
All the wrapper compilers do is add a variety of compiler and linker
flags to the command line and then invoke a back-end compiler. To be
specific: the wrapper compilers do not parse source code at all; they
are solely command-line manipulators, and have nothing to do with the
actual compilation or linking of programs. The end result is an MPI
executable that is properly linked to all the relevant libraries.
Customizing the behavior of the wrapper compilers is possible (e.g.,
changing the compiler [not recommended] or specifying additional
compiler/linker flags); see the Open MPI FAQ for more information.
Alternatively, starting in the Open MPI v1.5 series, Open MPI also
installs pkg-config(1) configuration files under $libdir/pkgconfig.
If pkg-config is configured to find these files, then compiling /
linking Open MPI programs can be performed like this:
shell$ gcc hello_world_mpi.c -o hello_world_mpi -g \
`pkg-config ompi-c --cflags --libs`
shell$
Open MPI supplies multiple pkg-config(1) configuration files; one for
each different wrapper compiler (language):
------------------------------------------------------------------------
ompi Synonym for "ompi-c"; Open MPI applications using the C
MPI bindings
ompi-c Open MPI applications using the C MPI bindings
ompi-cxx Open MPI applications using the C or C++ MPI bindings
ompi-f77 Open MPI applications using the C or "mpif.h" MPI bindings
ompi-f90 Open MPI applications using the C, "mpif.h" or "use mpi" MPI
bindings
------------------------------------------------------------------------
The following pkg-config(1) configuration files *may* be installed,
depending on which command line options were specified to Open MPI's
configure script. They are not necessary for MPI applications, but
may be used by applications that use Open MPI's lower layer support
libraries.
orte: Open MPI Run-Time Environment applicaions
opal: Open Portable Access Layer applications
===========================================================================
Running Open MPI Applications
-----------------------------
Open MPI supports both mpirun and mpiexec (they are exactly
equivalent). For example:
shell$ mpirun -np 2 hello_world_mpi
or
shell$ mpiexec -np 1 hello_world_mpi : -np 1 hello_world_mpi
are equivalent. Some of mpiexec's switches (such as -host and -arch)
are not yet functional, although they will not error if you try to use
them.
The rsh launcher accepts a -hostfile parameter (the option
"-machinefile" is equivalent); you can specify a -hostfile parameter
indicating an standard mpirun-style hostfile (one hostname per line):
shell$ mpirun -hostfile my_hostfile -np 2 hello_world_mpi
If you intend to run more than one process on a node, the hostfile can
use the "slots" attribute. If "slots" is not specified, a count of 1
is assumed. For example, using the following hostfile:
---------------------------------------------------------------------------
node1.example.com
node2.example.com
node3.example.com slots=2
node4.example.com slots=4
---------------------------------------------------------------------------
shell$ mpirun -hostfile my_hostfile -np 8 hello_world_mpi
will launch MPI_COMM_WORLD rank 0 on node1, rank 1 on node2, ranks 2
and 3 on node3, and ranks 4 through 7 on node4.
Other starters, such as the resource manager / batch scheduling
environments, do not require hostfiles (and will ignore the hostfile
if it is supplied). They will also launch as many processes as slots
have been allocated by the scheduler if no "-np" argument has been
provided. For example, running a SLURM job with 8 processors:
shell$ salloc -n 8 mpirun a.out
The above command will reserve 8 processors and run 1 copy of mpirun,
which will, in turn, launch 8 copies of a.out in a single
MPI_COMM_WORLD on the processors that were allocated by SLURM.
Note that the values of component parameters can be changed on the
mpirun / mpiexec command line. This is explained in the section
below, "The Modular Component Architecture (MCA)".
===========================================================================
The Modular Component Architecture (MCA)
The MCA is the backbone of Open MPI -- most services and functionality
are implemented through MCA components. Here is a list of all the
component frameworks in Open MPI:
---------------------------------------------------------------------------
MPI component frameworks:
-------------------------
allocator - Memory allocator
bml - BTL management layer
btl - MPI point-to-point Byte Transfer Layer, used for MPI
point-to-point messages on some types of networks
coll - MPI collective algorithms
crcp - Checkpoint/restart coordination protocol
dpm - MPI-2 dynamic process management
io - MPI-2 I/O
mpool - Memory pooling
mtl - Matching transport layer, used for MPI point-to-point
messages on some types of networks
op - Back end computations for intrinsic MPI_Op operators
osc - MPI-2 one-sided communications
pml - MPI point-to-point management layer
pubsub - MPI-2 publish/subscribe management
rcache - Memory registration cache
topo - MPI topology routines
Back-end run-time environment (RTE) component frameworks:
---------------------------------------------------------
errmgr - RTE error manager
ess - RTE environment-specfic services
filem - Remote file management
grpcomm - RTE group communications
iof - I/O forwarding
notifier - System/network administrator noficiation system
odls - OpenRTE daemon local launch subsystem
oob - Out of band messaging
plm - Process lifecycle management
ras - Resource allocation system
rmaps - Resource mapping system
rml - RTE message layer
routed - Routing table for the RML
snapc - Snapshot coordination
Miscellaneous frameworks:
-------------------------
backtrace - Debugging call stack backtrace support
carto - Cartography (host/network mapping) support
crs - Checkpoint and restart service
installdirs - Installation directory relocation services
maffinity - Memory affinity
memchecker - Run-time memory checking
memcpy - Memopy copy support
memory - Memory management hooks
paffinity - Processor affinity
pstat - Process status
sysinfo - Basic system information
timer - High-resolution timers
---------------------------------------------------------------------------
Each framework typically has one or more components that are used at
run-time. For example, the btl framework is used by the MPI layer to
send bytes across different types underlying networks. The tcp btl,
for example, sends messages across TCP-based networks; the openib btl
sends messages across OpenFabrics-based networks; the MX btl sends
messages across Myrinet MX / Open-MX networks.
Each component typically has some tunable parameters that can be
changed at run-time. Use the ompi_info command to check a component
to see what its tunable parameters are. For example:
shell$ ompi_info --param btl tcp
shows all the parameters (and default values) for the tcp btl
component.
These values can be overridden at run-time in several ways. At
run-time, the following locations are examined (in order) for new
values of parameters:
1. <prefix>/etc/openmpi-mca-params.conf
This file is intended to set any system-wide default MCA parameter
values -- it will apply, by default, to all users who use this Open
MPI installation. The default file that is installed contains many
comments explaining its format.
2. $HOME/.openmpi/mca-params.conf
If this file exists, it should be in the same format as
<prefix>/etc/openmpi-mca-params.conf. It is intended to provide
per-user default parameter values.
3. environment variables of the form OMPI_MCA_<name> set equal to a
<value>
Where <name> is the name of the parameter. For example, set the
variable named OMPI_MCA_btl_tcp_frag_size to the value 65536
(Bourne-style shells):
shell$ OMPI_MCA_btl_tcp_frag_size=65536
shell$ export OMPI_MCA_btl_tcp_frag_size
4. the mpirun command line: --mca <name> <value>
Where <name> is the name of the parameter. For example:
shell$ mpirun --mca btl_tcp_frag_size 65536 -np 2 hello_world_mpi
These locations are checked in order. For example, a parameter value
passed on the mpirun command line will override an environment
variable; an environment variable will override the system-wide
defaults.
Each component typically activates itself when relavant. For example,
the MX component will detect that MX devices are present and will
automatically be used for MPI communications. The SLURM component
will automatically detect when running inside a SLURM job and activate
itself. And so on.
Components can be manually activated or deactivated if necessary, of
course. The most common components that are manually activated,
deactivated, or tuned are the "BTL" components -- components that are
used for MPI point-to-point communications on many types common
networks.
For example, to *only* activate the TCP and "self" (process loopback)
components are used for MPI communications, specify them in a
comma-delimited list to the "btl" MCA parameter:
shell$ mpirun --mca btl tcp,self hello_world_mpi
To add shared memory support, add "sm" into the command-delimited list
(list order does not matter):
shell$ mpirun --mca btl tcp,sm,self hello_world_mpi
To specifically deactivate a specific component, the comma-delimited
list can be prepended with a "^" to negate it:
shell$ mpirun --mca btl ^tcp hello_mpi_world
The above command will use any other BTL component other than the tcp
component.
===========================================================================
Common Questions
----------------
Many common questions about building and using Open MPI are answered
on the FAQ:
http://www.open-mpi.org/faq/
===========================================================================
Got more questions?
-------------------
Found a bug? Got a question? Want to make a suggestion? Want to
contribute to Open MPI? Please let us know!
When submitting questions and problems, be sure to include as much
extra information as possible. This web page details all the
information that we request in order to provide assistance:
http://www.open-mpi.org/community/help/
User-level questions and comments should generally be sent to the
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