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The bidirectional bandwidth is the bandwidth test with both the nodes involved sending out a fixed number of back-to-back messages (equal to the window size) and waiting for the reply. This process is repeated for several iterations and the bandwidth is calculated based on the elapsed time (from the time sender sends the first message until the time it receives the reply back from the receiver) and the number of bytes sent by the sender. This test measures the maximum sustainable aggregate bandwidth by two nodes. It was performed inter/intra socket, inter node and GPU-inter/intra node.
