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No; Homa uses less buffer space than TCP. A recent paper on Aeolus claimed that Homa overloads buffers, resulting in dropped packets and poor performance. However, the paper was based on a false assumption about how buffers are managed in modern switches, and its results are invalid. See the Aeolus rebuttal for more information.

Homa is arguably optimal in its use of buffers. In order to achieve the best performance for a new message in an unloaded network, a sender must be able to unilaterally transmit enough data to cover the time it takes to get a packet to the receiver, process that packet in software, and return some sort of signal back to the sender. This is what Homa does; it calls this unscheduled data and uses the term rttBytes to refer to the amount of unscheduled data that may be sent for each message. If a sender sends less than rttBytes before hearing back from the receiver, then network bandwidth will be wasted. Buffering will occur at the receiver’s downlink if several new messages begin transmitting around the same time. With Homa, the receiver detects the buffering as soon as it receives one packet from each message, and it immediately takes steps to reduce the buffering by withholding grants; again, this is optimal.

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