Update: The MSMPI Debugger Extension is now shipped as part of HPC Pack 2012 SP1 Toolpack. You can get to the download page from the MSMPI landing page


The MSMPI Debugger Extension (MSMPIDBG) is an extension to Windows Debugger (WinDbg) that facilitates simultaneous debugging of multiple MPI processes (using the MSMPI library). The extension has the following features:

  • Supports the debugging of multiple MPI processes (using the MSMPI library) from one debugging session of WinDbg.

  • Supports three major debugging scenarios: launch under the debuggers, attach to running processes, and post-mortem debugging of dump files.

  • Scales to 1K processes.

  • Merges output from multiple processes to help with problem analysis.

  • Supplies several built-in functions that provide the user with MPI-specific information including:

    • !msg will display the active messages in the MPI message queues (unexpected receive queue, posted receive queue, outstanding send queue).

    • !mpihandle will display detailed information about MPI handles (MPI request, MPI datatype, MPI communicator).

    • !conn will display current connectivity information for MPI processes.

Send an email to askmpi@microsoft.com for instructions on how to access the beta program. The beta download will include the installation and a user guide, which includes a lot of screenshots and examples, to get you started. In the next blog post we will have some tutorials with videos, so keep watching this blog for more updates.