A mistake related to
MPI_Comm_free()is freeing them in different orders on the involved processes. The MPI standard specifies that
MPI_Comm_free()must be entered by the processes in the communicator collectively. Some MPIs including Intel® MPI Library deadlock if this rule is broken, whereas others implement
MPI_Comm_free()as a local call with no communication.
To ensure that this error is detected all the time, Intel® Trace Collector treats
MPI_Comm_free()just like the other collective operations. There is no special error message for
GLOBAL:COLLECTIVE:COMM_FREE_MISMATCH, it will be reported as a mismatch between collective calls (
GLOBAL:COLLECTIVE:OPERATION_MISMATCH) or a deadlock, so
GLOBAL:COLLECTIVE:COMM_FREE_MISMATCHjust refers to the check which enables or disables this test, not a specific error instance.