For greater control, a user may log events directly, using the MPE library. MPE comprises useful tools that forms a companion library for enhancing MPI programs. It was originally designed for use with MPICH, but now is independent of MPICH and can be used with any implementation of MPI. It contains non-MPI synchronization functions (for serialization), graphics routines (see ), and logging functions. It is these logging routines that are called by the profiling library described in Section The MPI Profiling Interface , rather than CLOG directly.
The usefulness of using this library to prepare logfiles for Jumpshot is that a user (or another library) can log events and states that are directly related to the application or library independently of the MPI calls made. One can use the MPE logging functions either without any automated logging at all or in conjunction with it. A large-scale example of use with a library is given in Section Instrumenting a Mathematical Library .