100 строки
3.9 KiB
Plaintext
100 строки
3.9 KiB
Plaintext
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Feb 10, 2012
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---------------
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***************************************************************************
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IMPORTANT NOTE
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JAVA BINDINGS ARE PROVIDED ON A "PROVISIONAL" BASIS - I.E., THEY ARE NOT
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PART OF THE CURRENT OR PROPOSED MPI-3 STANDARDS. THUS, INCLUSION OF
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JAVA SUPPORT IS NOT REQUIRED BY THE STANDARD. CONTINUED INCLUSION
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OF THE JAVA BINDINGS IS CONTINGENT UPON ACTIVE USER INTEREST AND
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CONTINUED DEVELOPER SUPPORT
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***************************************************************************
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This version of Open MPI provides support for Java-based
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MPI applications. At the time of this writing, not all MPI functions
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are supported. However, work on extending the Java bindings to
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provide full MPI coverage is underway.
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The rest of this document provides step-by-step instructions on
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building OMPI with Java bindings, and compiling and running
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Java-based MPI applications
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============================================================================
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Building Java Bindings
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If this software was obtained as a developer-level
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checkout as opposed to a tarball, you will need to start your build by
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running ./autogen.pl. This will also require that you have a fairly
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recent version of autotools on your system - see the HACKING file for
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details.
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Java support requires that Open MPI be built at least with shared libraries
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(i.e., --enable-shared) - any additional options are fine and will not
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conflict. Note that this is the default for Open MPI, so you don't
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have to explicitly add the option. The Java bindings will build only
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if --enable-mpi-java is specified, and a JDK is found in a typical
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system default location.
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If the JDK is not in a place where we automatically find it, you can
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specify the location. For example, this is required on the Mac
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platform as the JDK headers are located in a non-typical location. Two
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options are available for this purpose:
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--with-jdk-bindir=<foo> - the location of javac and javah
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--with-jdk-headers=<bar> - the directory containing jni.h
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For simplicity, typical configurations are provided in platform files
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under contrib/platform/hadoop. These will meet the needs of most
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users, or at least provide a starting point for your own custom
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configuration.
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In summary, therefore, you can configure the system using the
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following Java-related options:
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./configure --with-platform=contrib/platform/hadoop/<your-platform>
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...
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or
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./configure --enable-mpi-java --with-jdk-bindir=<foo>
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--with-jdk-headers=bar ...
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or simply
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./configure --enable-mpi-java ...
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if jdk is in a "standard" place that we automatically find.
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----------------------------------------------------------------------------
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Running Java Applications
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For convenience, the "mpijavac" wrapper compiler has been provided for
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compiling Java-based MPI applications. It ensures that all required MPI
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libraries and class paths are defined. You can see the actual command
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line using the --showme option, if you are interested.
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Once your application has been compiled, you can run it with the
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standard "mpirun" command line:
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mpirun <options> java <your-java-options> <my-app>
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For convenience, mpirun has been updated to detect the "java" command
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and ensure that the required MPI libraries and class paths are defined
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to support execution. You therefore do NOT need to specify the Java
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library path to the MPI installation, nor the MPI classpath. Any class
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path definitions required for your application should be specified
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either on the command line or via the CLASSPATH environmental
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variable. Note that the local directory will be added to the class
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path if nothing is specified.
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As always, the "java" executable, all required libraries, and your application classes
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must be available on all nodes.
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----------------------------------------------------------------------------
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If you have any problems, or find any bugs, please feel free to report
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them to Open MPI user's mailing list (see
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http://www.open-mpi.org/community/lists/ompi.php).
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