Using valgrind to spot error in mpi code

Question

I have a code which works perfect in serial but with mpirun -n 2 ./out it gives the following error:

./out\': malloc(): smallbin double linked l         


        

Answer 1

Note that with the invocation above,

valgrind --leak-check=yes mpirun -n 2 ./out

you are running valgrind on the program mpirun, which presumably has been extensively tested and works correctly, and not the program ./out, which you know to have a problem.

To run valgrind on your test program you will want to do:

mpirun -n 2 valgrind --leak-check=yes ./out

Which uses mpirun to launch 2 processes, each running valgrind --leak-check=yes ./out.