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From: Joris van Rantwijk <joris@jorisvr.nl>
To: Ben Hutchings <bhutchings@solarflare.com>
Cc: netdev@vger.kernel.org
Subject: Re: Question about LRO/GRO and TCP acknowledgements
Date: Sun, 12 Jun 2011 09:51:31 +0200	[thread overview]
Message-ID: <20110612095131.6d924082@konijn> (raw)
In-Reply-To: <1307850224.22348.626.camel@localhost>


On 2011-06-12, Ben Hutchings <bhutchings@solarflare.com> wrote:
> LRO implementations (and GRO) are expected to put the actual segment
> size in skb_shared_info(skb)->gso_size on the aggregated skb.  TCP
> will then use that rather than the aggregated payload size when
> deciding whether to defer an ACK.

Thanks. I see that indeed gso_size is being used for MSS calculations
instead of the total GRO size.

However, I'm not sure that this completely answers my question.
I am not so much concerned about quick ACK vs delayed ACK.
Instead, I'm looking at the total number of ACKs transmitted.
The sender depends on the _number_ of ACKs to update its congestion
window.

As far as I can see, current code will send just one ACK per coalesced
GRO bundle, while the sender expects one ACK per two segments.

Thanks,
Joris.

  reply	other threads:[~2011-06-12  7:51 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-11 19:59 Question about LRO/GRO and TCP acknowledgements Joris van Rantwijk
2011-06-12  3:43 ` Ben Hutchings
2011-06-12  7:51   ` Joris van Rantwijk [this message]
2011-06-12  9:07     ` Eric Dumazet
2011-06-12  9:30       ` Joris van Rantwijk
2011-06-12 10:48         ` Eric Dumazet
2011-06-12 11:24           ` Joris van Rantwijk
2011-06-12 12:01             ` Alexander Zimmermann
2011-06-12 14:57             ` Eric Dumazet
2011-06-12 19:37               ` Joris van Rantwijk
2011-06-14 10:53                 ` Ilpo Järvinen
2011-06-14 19:37                   ` Joris van Rantwijk
2011-06-13 17:55               ` Rick Jones
2011-06-13 17:34 ` Rick Jones

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