Suppose that the profiler wishes to accumulate the total amount of data sent by the MPI_SEND function, along with the total elapsed time spent in the function. This could trivially be achieved thus
static int totalBytes; static double totalTime;int MPI_SEND(void * buffer, const int count, MPI_Datatype datatype, int dest, int tag, MPI_comm comm) { double tstart = MPI_Wtime(); /* Pass on all the arguments */ int extent; int result = PMPI_Send(buffer,count,datatype,dest,tag,comm);
MPI_Type_size(datatype, &extent); /* Compute size */ totalBytes += count*extent;
totalTime += MPI_Wtime() - tstart; /* and time */
return result; }