Re: TSO and IPoIB performance degradation

From: Michael S. Tsirkin
Date: Thu Mar 09 2006 - 19:36:50 EST


Quoting r. Michael S. Tsirkin <mst@xxxxxxxxxxxxxx>:
> Or does __tcp_ack_snd_check delay until we have at least two full sized
> segments?

What I'm trying to say, since RFC 2525, 2.13 talks about
"every second full-sized segment", so following the code from
__tcp_ack_snd_check, why does it do

/* More than one full frame received... */
if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss

rather than

/* At least two full frames received... */
if (((tp->rcv_nxt - tp->rcv_wup) >= 2 * inet_csk(sk)->icsk_ack.rcv_mss

--
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies
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