XMPI_Buoy - LAM/MPI-specific function to drop a buoy in
the XMPI trace stream.
SYNOPSIS
#include <mpi.h>
int
XMPI_Buoy(const char* name)
INPUT PARAMETER
name - buoy name (string)
NOTES
The LAM implementation of MPI is integrated with the XMPI
run/debug viewer. It can generate tracefiles and on-the-
fly trace streams suitable for display in XMPI.
A new functionality in XMPI is the ability to view "buoys"
in the trace stream that can be helpful in marking partic
ular sections of code. LAM/MPI allows the dropping of
buoys with the XMPI_Buoy function. Calling XMPI_Buoy with
a string will drop a bouy of that name (if tracing is
enabled) in the trace stream. Dropping a buoy is a local
action; the call will return immediately. The buoy is
dropped in the trace stream of the local rank, and will
appear on the corresponding rank timeline in XMPI.
The name can be a maximum of 32 characters long; if it is
longer, it will be truncated.
If this function is invoked and tracing is not active, the
buoy is ignored.
There is no profiling version of this function.
This is a LAM/MPI-specific function and is intended mainly
for use with XMPI. If this function is used, it should be
used in conjunction with the LAM_MPI C preprocessor macro
#if LAM_MPI
XMPI_Buoy("my function begins");
// ... message passing code
XMPI_Buoy("my function ends");
#endif
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and
MPI_WTICK ) have an additional argument ierr at the end of
the argument list. ierr is an integer and has the same
meaning as the return value of the routine in C. In For
tran, MPI routines are subroutines, and are invoked with
All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of
type INTEGER in Fortran.
ERRORS
If an error occurs in an MPI function, the current MPI
error handler is called to handle it. By default, this
error handler aborts the MPI job. The error handler may
be changed with MPI_Errhandler_set ; the predefined error
handler MPI_ERRORS_RETURN may be used to cause error val
ues to be returned (in C and Fortran; this error handler
is less useful in with the C++ MPI bindings. The prede
fined error handler MPI::ERRORS_THROW_EXCEPTIONS should be
used in C++ if the error value needs to be recovered).
Note that MPI does not guarantee that an MPI program can
continue past an error.
All MPI routines (except MPI_Wtime and MPI_Wtick ) return
an error value; C routines as the value of the function
and Fortran routines in the last argument. The C++ bind
ings for MPI do not return error values; instead, error
values are communicated by throwing exceptions of type
MPI::Exception (but not by default). Exceptions are only
thrown if the error value is not MPI::SUCCESS .
Note that if the MPI::ERRORS_RETURN handler is set in C++,
while MPI functions will return upon an error, there will
be no way to recover what the actual error value was.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_ARG
- Invalid argument. Some argument is invalid and
is not identified by a specific error class. This
is typically a NULL pointer or other such error.
MPI_ERR_INTERN
- An internal error has been detected. This is
fatal. Please send a bug report to the LAM mailing
list (see http://www.lam-mpi.org/contact.php ).
SEE ALSO
XMPI_Coloron, XMPI_Coloroff
LOCATION
xbuoy.c
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