Hello, The MPI standard says "However, MPI implementations are not allowed to change the index of a performance variable or to delete a variable once it has been added to the set. When a variable becomes inactive, e.g., through dynamic unloading, accessing its value should return a corresponding error code." Does it imply, 1) MPI_T_pvar_get_num() will return a N that counts both active and inactive pvars 2) MPI_T_pvar_get_info(par_index, ...,) may return MPI_T_ERR_INVALID_INDEX even for a par_index < N 3) When a pvar is re-activated, it keeps its old index? These are not obvious in the standard. Thanks. --Junchao Zhang