Biband

The Biband measures the cumulative bandwidth and message rate values. To achieve this, the first half of ranks communicates with the second half using MPI_Isend/MPI_Recv/MPI_Wait calls. In case of the odd number of processes, one of them does not participate in the message exchange. The bunch of MPI_Isend calls are issued by each rank in the first half of ranks to its counterpart from the second half of ranks, and vice versa. The number of messages issued at each iteration step is defined with the MAX_WIN_SIZE constant. The same buffer is used for every send event in the iteration.

Uniband Definition

Property

Description

Measured pattern

(MAX_WIN_SIZE *MPI_Isend)/(MAX_WIN_SIZE *MPI_Irecv)/Waitall

MPI data type

MPI_BYTE (origin and target)

Reported message rate

2*MAX_WIN_SIZE*N/MAX(process_timings), where N is the number of communicating pairs

Reported throughput

MBps (msg_rate *size_in_bytes/ 1048576.0)