Measuring Communication and Computation Overlap
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Measuring Pure Communication Time
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallgather
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallgather_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallgatherv
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallgatherv_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallreduce
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iallreduce_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ialltoall
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ialltoall_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ialltoallv
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ialltoallv_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ibarrier
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ibarrier_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ibcast
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ibcast_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Igather
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Igather_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Igatherv
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Igatherv_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ireduce
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ireduce_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ireduce_scatter
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Ireduce_scatter_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iscatter
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iscatter_pure
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iscatterv
                                                    
                                                    
                                                
                                                    
                                                    
                                                        Iscatterv_pure
                                                    
                                                    
                                                
                                            
                                        Checking Results
To check whether your MPI implementation is working correctly, you can use the CPP flag -DCHECK.
Activate the CPP flag -DCHECK through the CPPFLAGS variable and recompile the Intel(R) MPI Benchmarks executable files. Every message passing result from the Intel(R) MPI Benchmarks are checked against the expected outcome. Output tables contain an additional column called Defects that displays the difference as floating-point numbers.
     NOTE: 
   
 The -DCHECK results are not valid as real benchmark data. Deactivate -DCHECK and recompile to get the proper results.