The elapsed (wall-clock) time between two points in an MPI program can be
computed using MPI_Wtime:
double t1, t2; t1 = MPI_Wtime(); ... t2 = MPI_Wtime(); printf( "Elapsed time is %f\n", t2 - t1 );The value returned by a single call to MPI_Wtime has little value.
127 The times are local; the attribute MPI_WTIME_IS_GLOBAL may be used to determine if the times are also synchronized with each other for all processes in MPI_COMM_WORLD.