Robert Watson writes: > The immediate practical benefit is > clear: if the queueing at the ifnet layer is unnecessary, it is entirely > avoided, skipping enqueue, dequeue, and four mutex operations.
This is indeed nice, but for TCP I think the benefit would be far greater if somebody would PLEASE, PLEASE, PLEASE implement TSO (aka LSO). Consider a 1460 byte mss and 64KB of data that is ready to be sent. With the current model, that is 45 separate calls to if_output(), and 45*4 (queuing) + 45 (tx routine) == 225 mutex operations. Using your model, we're down to 45 mutex operations. Using TSO, we have 4 + 1 == 5 mutex operations with the old model, and 1 with the your model. This is not even considering all the other overhead involved in 45 transmits vs TSO... Just something to think about.. Drew _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
