From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH net-next] tcp: TSO packets automatic sizing
Date: Sun, 25 Aug 2013 20:58:37 -0700
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Cc: Neal Cardwell <ncardwell@google.com>,
	David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>, Van Jacobson <vanj@google.com>,
	Tom Herbert <therbert@google.com>
To: Yuchung Cheng <ycheng@google.com>
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On Sun, 2013-08-25 at 19:22 -0700, Eric Dumazet wrote:
> On Sun, 2013-08-25 at 17:37 -0700, Eric Dumazet wrote:
> > On Sun, 2013-08-25 at 15:01 -0700, Yuchung Cheng wrote:
> > 
> > > Any idea to get rid of this undesirable extra RTT delay?
> > 
> > Its probably a bug in the push code.
> 
> For exact write/send of a multiple of MSS, I think following patch
> should fix the bug.
> 
> If we filled a packet, we must send it.
> 
> For the other problem, I think its related to Nagle.

Oh well, thats the tcp_tso_should_defer() again.

        /* If a full-sized TSO skb can be sent, do it. */
        if (limit >= min_t(unsigned int, sk->sk_gso_max_size,
                           sk->sk_gso_max_segs * tp->mss_cache))
                goto send_now;

I'll send a V2 of the patch