The MPI profiling interface provides a mechanism by which implementors
of profiling tools can collect performance information without access
to the underlying MPI implementation source code.
Because HP-MPI provides several options for profiling your
applications, you may not need the profiling interface to write
your own routines. HP-MPI makes use of MPI profiling interface mechanisms
to provide the diagnostic library for debugging. In addition, HP-MPI
provides tracing and lightweight counter instrumentation. For details,
refer to
The profiling interface allows you to intercept calls made
by the user program to the MPI library. For example, you may want
to measure the time spent in each call to a certain library routine
or create a log file. You can collect your information of interest
and then call the underlying MPI implementation through an alternate
entry point as described below.
All routines in the HP-MPI library begin with the MPI_ prefix. Consistent with the “Profiling
Interface” section of the MPI 1.2 standard, routines are
also accessible using the PMPI_ prefix (for example, MPI_Send and PMPI_Send access the same routine).
To use the profiling interface, write wrapper versions of
the MPI library routines you want the linker to intercept. These
wrapper routines collect data for some statistic or perform some
other action. The wrapper then calls the MPI library routine using
its PMPI_ prefix.
Fortran
profiling interface |
 |
When writing profiling routines, do not call Fortran entry
points from C profiling routines, and visa versa. In order to profile
Fortran routines, separate wrappers need to be written for the Fortran
calls.
For example:
#include <stdio.h>
#include <mpi.h>
int MPI_Send(void *buf, int count, MPI_Datatype type,
int to, int tag, MPI_Comm comm)
{
printf("Calling C MPI_Send to %d\n", to);
return PMPI_Send(buf, count, type, to, tag, comm);
}
#pragma weak (mpi_send mpi_send)
void mpi_send(void *buf, int *count, int *type, int *to,
int *tag, int *comm, int *ierr)
{
printf("Calling Fortran MPI_Send to %d\n", *to);
pmpi_send(buf, count, type, to, tag, comm, ierr);
} |
C++
profiling interface |
|
The HP-MPI C++ bindings are wrappers to the C calls. No profiling library
exists for the C++ bindings. To profile the C++ interface, write
the equivalent C wrapper version of the MPI library routines you
want to profile. See the section above for details on profiling
the C MPI libraries.
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