I am running into an issue with Darshan using MVAPICH2 on gpfs. If I configure MVAPICH2 with the --with-file-system=ufs+nfs option then Darshan behaves correctly, however if I configure with the --with-file-system=ufs+nfs+gpfs option then Darshan hangs, even for a simple MPI hello world. The below screenshot from Totalview shows that it is hanging inside a call to PMPI_File_write_at_all during darshan_core_shutdown. We created a standalone MPIIO test code to try to reproduce this issue but our code does not hang. I would appreciate any insight into why Darshan is hanging.