[mpich-discuss] Debugging mpi program using mpich

[Dave Goodell]

On Feb 26, 2013, at 9:39 AM CST, Mathieu Dutour wrote:

> I used mpich-3.0.1 with debugging options and the program ran correctly
> but at the end returned some errors indicated later.
> I thank mpich for finding those errors that other mpi implementation did
> not find but I wonder if there is a way to transform this into more useful
> debugging informations.

High-quality patches to improve the output are welcome.  We primarily view these leak-checking messages as tools for us (the core developers of MPICH), not for end-user consumption.  So we probably won't spend any time to change these messages ourselves.

>   Mathieu
> 
> PS: The errors retuned after leaving:
> leaked context IDs detected: mask=0x9d7380 mask[0]=0x3fffffff
> In direct memory block for handle type GROUP, 3 handles are still allocated

[…]

In case you have not yet found your bug, these messages are indicating that you are leaking MPI objects, especially communicators, groups, and datatypes.  It could be that they are leaked indirectly because you have not completed an outstanding request (via MPI_Wait or similar), as indicated by the lines with "REQUEST" in them.

-Dave