foMPI implements the one-sided chapter of MPI-3.0 standard. It offers a
C and a Fortran interface.

This library was written by Robert Gerstenberger, Maciej Besta and
Torsten Hoefler and is copyrighted by the Trustees of the University
of Illinois (c) 2012. See LICENSE for details on the license.

Building
========

Compiler
--------
Currently the implementation uses inline assembly for intra-node atomics
and SSE for a fast intra-node memory copy, which isn't supported by the
Cray compiler. We used primarily gcc, but also tested the Intel compiler
and other compiler might work as well.

The Fortran interface can be accessed in the Fortran 77 way (include
'fompif.h') or the Fortran 90 way (use fompi). Since the structure of a
module file depends on the compiler and you wish to build foMPI with a
different compiler than your application, please use the following
scheme:
1) load the compiler with whom you intend to compile foMPI
2) make fompi.ar
3) load the compiler with whom you intend to compile your application
4) rm -f fompi_fortran.o module_fompi.o fompi.{compiler-specific file 
   extension for Fortran module files, .mod for gcc}
5) make fompi.ar
At the moment the name mangling of the Fortran wrapper is hard-coded
(single underscore). If you need to change this for your compiler,
please have a look at line 6 in fompi_fortran.c .

Dependencies
------------
The foMPI tar archive comes with two additional libaries: MPITypes and
libtopodisc, which are included. Just type "make" and those libraries and
the foMPI object files will be built, and packed together in the
ar-archive named fompi.ar. Also a little test program will be built.
If you wish to built the libraries with a different compiler, please use
"make mpitypes" or "make libtopodisc".  

foMPI also needs the m4 macro processor.

* m4 is available from http://www.gnu.org/software/m4/ .
* MPITypes: For more information see the homepage 
  (http://www.mcs.anl.gov/mpitypes/) or their paper from the EuroMPI
  2009 conference (R. Ross, "MPITypes: Processing MPI Datatypes Outside
  MPI").
* Libtopodisc was provided by William Gropp
  (http://www.cs.illinois.edu/~wgropp/ ).

Includes/Linking
----------------
Additional includes to build your application with foMPI are:
-I{PATH to foMPI}

Additional parameter for linking your application with foMPI are:
{PATH to foMPI}/fompi.ar 
-L{PATH to foMPI}/mpitypes/install/lib -lmpitypes
-ldmapp
-L{PATH to foMPI}/libtopodisc -ltopodisc (if compiled with XPMEM
support)

Build parameter
---------------
The building parameter can be found in the Makefile.inc file.
You can choose your appropriate compiler (CC), flags (CCFLAGS) and
additional foMPI build parameter. At the moment foMPI supports the
following parameter:
* -DNA: enables the Notified Access extension
* -DXPMEM: enables XPMEM support for intra-node communication
* -DNDEBUG: disables additional error checking

If you experience problems with foMPI please try to enable the
additional error checking or try removing the XPMEM support.


Using foMPI
===========

All MPI one-sided functions are prefixed with foMPI instead of MPI.
Additional all constants like foMPI_LOCK_{SHARED,EXLCUSIVE}, the error
codes, asserts (though not supported at the moment), flavor, memory
model and MPI_Ops for the accumulate-derived communication functions
need to be prefixed with foMPI. Below you find a complete list of
all implemented constants.

The datatypes MPI_Win and MPI_Request (if used with foMPI RMA functions
that take requests) need to be renamed to foMPI_Win or foMPI_Request.
foMPI_Requests are not compatible with MPI_Requests, and can only be
used with foMPI wait and test functions.

Some functions needed to be overloaded to have foMPI work properly
(MPI_Init, MPI_Finalize, MPI_Type_free). The wait and test functions for
foMPI requests can't be mixed with normal MPI requests. For a full list
of overloaded functions, please check the list below.

Apart from prefixing elements of the MPI one-sided scope the function
interfaces are declared as in the standard. See fompi.h for the full
function prototypes.

Below you can find a complete list of implemented and not implemented
functions of the one-sided chapter.

foMPI implements the unified memory model.

MPI Datatypes
-------------

foMPI supports all datatypes that are supported by MPITypes for
foMPI_Put/foMPI_Get. The following datatypes are in the fast path for
these two communication functions:
* MPI_CHAR
* MPI_UINT64_T
* MPI_DOUBLE
* MPI_INT

All MPI datatypes are supported for the accumulate-based communication
functions except:
* handles from MPI_TYPE_CREATE_F90_INTEGER
* MPI_INTEGER16
* handles from MPI_TYPE_CREATE_F90_REAL
* MPI_REAL2
* MPI_CXX_BOOL
* handles from MPI_TYPE_CREATE_F90_COMPLEX
* MPI_CXX_FLOAT_COMPLEX
* MPI_CXX_DOUBLE_COMPLEX
* MPI_CXX_LONG_DOUBLE_COMPLEX

The following combinations of MPI datatypes and MPI_Ops are
hardware-supported:
* MPI_DOUBLE/MPI_{BAND/BOR/BXOR}
* MPI_INT64_T/MPI_{BAND/BOR/BXOR}
* MPI_INT64_T/MPI_SUM

Fortran
-------
All communication functions take a displacement parameter, which is of
the integer(kind=MPI_ADDRESS_KIND) type. To ensure compatibility with the
C wrapper code, please use a variable for the displacement parameter
instead of using a constant (which will be transfered as 4 byte integer
instead of the bigger integer(kind=MPI_ADDRESS_KIND)).

On our test system, we experienced problems with MPI_Get_address, which
gives different results for the same location if called from C and
Fortran. Since our library is implemented in C, this is an issue if you
intend to use dynamic windows.
We included a test_address subdirectory, which contains a small test
program for this problem. If all three locations are the same, you are
fine. If not, please use foMPI_Get_address instead.


Questions
=========

If you have additional questions, feel free to contact me under the
following e-mail address: Robert Gerstenberger <[email protected]>.


Citation
========

Any published work which uses this software should include the 
following citation:

----------------------------------------------------------------------
R. Gerstenberger, M. Besta and T. Hoefler: Enabling Highly-Scalable
Remote Memory Access Programming with MPI-3 One Sided. In: Proceedings
of the International Conference on High Performance Computing,
Networking, Storage and Analysis (SC'13)
----------------------------------------------------------------------


Implemented function
====================

Window creation
---------------
* foMPI_Win_create
* foMPI_Win_allocate
* foMPI_Win_create_dynamic
* foMPI_Win_free

* foMPI_Win_attach
* foMPI_Win_detach


Synchronization
---------------
* foMPI_Win_fence

* foMPI_Win_post
* foMPI_Win_start
* foMPI_Win_complete
* foMPI_Win_wait
* foMPI_Win_test

* foMPI_Win_lock
* foMPI_Win_unlock
* foMPI_Win_lock_all
* foMPI_Win_unlock_all

* foMPI_Win_flush
* foMPI_Win_flush_all
* foMPI_Win_flush_local
* foMPI_Win_flush_local_all
* foMPI_Win_sync


Communication
-------------
* foMPI_Put
* foMPI_Get
* foMPI_Accumulate
* foMPI_Get_accumulate
* foMPI_Fetch_and_op
* foMPI_Compare_and_swap

* foMPI_Rput
* foMPI_Rget
* foMPI_Raccumulate
* foMPI_Rget_accumulate


Miscellaneous
-------------
* foMPI_Win_get_group

* foMPI_Win_set_name
* foMPI_Win_get_name


Overloaded functions
====================

Additional to MPI one-sided functions also the following functions need
to be overloaded:

* foMPI_Type_free
* foMPI_Init
* foMPI_Finalize

All of them above will call their MPI equivalent with the passed
parameters, but do additional work for the foMPI implementation.

* foMPI_Wait
* foMPI_Test

These functions can only be used together with foMPI_Requests and can't
handle normal MPI_Request. All other wait oder test routines are not
implemented at the moment.


Not implemented functions
=========================

* foMPI_Win_allocate_shared
* foMPI_Win_shared_query
* foMPI_Win_get_attr
* foMPI_Win_set_attr
* foMPI_Win_delete_attr
* foMPI_Win_set_errhandler
* foMPI_Win_call_errhandler
* foMPI_Win_set_info
* foMPI_Win_get_info


Constants
=========

Create flavor
-------------
* foMPI_WIN_FLAVOR_CREATE
* foMPI_WIN_FLAVOR_ALLOCATE
* foMPI_WIN_FLAVOR_DYNAMIC


Memory model
------------
* foMPI_WIN_SEPARATE
* foMPI_WIN_UNIFIED


Asserts
-------
* foMPI_MODE_NOCHECK
* foMPI_MODE_NOSTORE
* foMPI_MODE_NOPUT
* foMPI_MODE_NOPRECEDE
* foMPI_MODE_NOSUCCEED
Asserts are not used at the moment, but will be accepted by the library.


Accumulate operations
---------------------
* foMPI_SUM
* foMPI_PROD
* foMPI_MAX
* foMPI_MIN
* foMPI_LAND
* foMPI_LOR
* foMPI_LXOR
* foMPI_BAND
* foMPI_BOR
* foMPI_BXOR
* foMPI_MAXLOC
* foMPI_MINLOC
* foMPI_REPLACE
* foMPI_NO_OP


Lock type
---------
* foMPI_LOCK_SHARED
* foMPI_LOCK_EXCLUSIVE


Error codes
-----------
* foMPI_ERROR_RMA_NO_SYNC
* foMPI_ERROR_RMA_DATATYPE_MISMATCH
* foMPI_ERROR_RMA_NO_LOCK_HOLDING
* foMPI_ERROR_RMA_SYNC_CONFLICT
* foMPI_ERROR_RMA_WIN_MEM_NOT_FOUND
* foMPI_OP_NOT_SUPPORTED
* foMPI_DATATYPE_NOT_SUPPORTED
* foMPI_NAME_ABBREVIATED