FAQ

Frequently asked questions

• My UPC++ app uses async remote function invocation and it seems to hang in a barrier.

This could be caused by a bug in the GASNet non-blocking barrier implementation for shared-memory (PSHM), which actually blocks when UPC++ calls the supposedly non-blocking barrier (gasnet_barrier_notify). To work around this issue, please try to set the following environment variable to disable the PSHM feature in GASNet before running the UPC++ app. See here for more details about this issue.

#!sh
export GASNET_SUPERNODE_MAXSIZE=1  ## disable the process shared memory (pshm) feature in GASNet
mpirun -np 4 ./app