The DUMPI package provides libraries to collect and read traces of MPI applications. Like Open Trace Format (OTF) traces, DUMPI traces are obtained by linking the application with a library that uses the PMPI interface to intercept MPI calls. The DUMPI format records more information than OTF, including the full signature of all MPI-1 and MPI-2 subroutine calls. With this additional detail we are able to more accurately simulate an application with SST/macro. The DUMPI format also records return values and MPI request information. This allows error checking and permits us to match immediate mode MPI operations with the MPI operations that complete them. In addition, DUMPI allows individual functions to be profiled instead of the entire program. Processor hardware performance counter information can also be stored in DUMPI files using the Performance Application Programming Interface (PAPI). This allows information such as cache misses and floating point operations to be logged. Such data is recorded both within and between MPI calls.