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) 2006-2009 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 list): firstname.lastname@example.org email@example.com Because of spam, only subscribers are allowed to post to these lists (ensure that you subscribe with and post from exactly the same e-mail address -- firstname.lastname@example.org is considered different than email@example.com!). Visit these pages to subscribe to the lists: http://www.open-mpi.org/mailman/listinfo.cgi/users http://www.open-mpi.org/mailman/listinfo.cgi/devel 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 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 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 (10 July 2009): 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 1.3 through 1.3.2) - 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); more testing and support is expected later in the Open MPI v1.3.x series. 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 - 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. - Asynchronous message passing progress using threads can be turned on with the --enable-progress-threads option to configure. Asynchronous message passing progress is only supported with devices that support MPI_THREAD_MULTIPLE, but is only very lightly tested (and may not provide very much performance benefit). 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 two MPI network models available: "ob1" and "cm". "ob1" uses 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 - Portals - Quadrics Elan - Shared memory - TCP - SCTP - uDAPL - "cm" supports a smaller number of networks (and they cannot be used together), but may provide better better overall MPI performance: - Myrinet MX (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. 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 cm ... - Myrinet 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" PML 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. =========================================================================== 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-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. --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 (both support for MPI_THREAD_MULTIPLE and asynchronous progress) 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-threads and/or --enable-progress-threads. --enable-mpi-threads Allows the MPI thread level MPI_THREAD_MULTIPLE. See --with-threads; this is currently disabled by default. --enable-progress-threads Allows asynchronous progress in some transports. See --with-threads; this is currently disabled by default. See the above note about asynchronous progress. --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-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. --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-ptmalloc2-internal ***NOTE: This option no longer exists. This option was introduced in Open MPI v1.3 and was then removed in Open MPI v1.3.2. Open MPI fundamentally changed how it uses ptmalloc2 support in v1.3.2 such that the --enable-ptmalloc2-internal flag was no longer necessary. It can still harmlessly be supplied to Open MPI's configure script, but a warning will appear about how it is an unrecognized option. In v1.3 and v1.3.1, Open MPI built the ptmalloc2 library as a standalone library that users could choose to link in or not (by adding -lopenmpi-malloc to their link command). Using this option restored pre-v1.3 behavior of *always* forcing the user to use the ptmalloc2 memory manager (because it is part of libmpi). Starting with v1.3.2, ptmalloc2 is always built into Open MPI, but is only activated in certain scenarios. --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. 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. =========================================================================== 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. =========================================================================== 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. =========================================================================== 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 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 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 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. =========================================================================== 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 user's mailing list (firstname.lastname@example.org). Because of spam, only subscribers are allowed to post to this list (ensure that you subscribe with and post from *exactly* the same e-mail address -- email@example.com is considered different than firstname.lastname@example.org!). Visit this page to subscribe to the user's list: http://www.open-mpi.org/mailman/listinfo.cgi/users Developer-level bug reports, questions, and comments should generally be sent to the developer's mailing list (email@example.com). Please do not post the same question to both lists. As with the user's list, only subscribers are allowed to post to the developer's list. Visit the following web page to subscribe: http://www.open-mpi.org/mailman/listinfo.cgi/devel Make today an Open MPI day!