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From: Neal Cardwell <ncardwell@google.com>
To: Yuchung Cheng <ycheng@google.com>
Cc: David Miller <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Nandita Dukkipati <nanditad@google.com>,
	Netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH 4/4 net-next] tcp: use RTT from SACK for RTO
Date: Sun, 21 Jul 2013 23:40:07 -0400	[thread overview]
Message-ID: <CADVnQykoQiGEvHsmtfjhVVGZPDNhHz6BqsNE+s-0Bjf+Q+Gx5A@mail.gmail.com> (raw)
In-Reply-To: <1374385170-358-4-git-send-email-ycheng@google.com>

On Sun, Jul 21, 2013 at 1:39 AM, Yuchung Cheng <ycheng@google.com> wrote:
> If RTT is not available because Karn's check has failed or no
> new packet is acked, use the RTT measured from SACK to estimate
> the RTO. The sender can continue to estimate the RTO during loss
> recovery or reordering event upon receiving non-partial ACKs.
>
> This also changes when the RTO is re-armed. Previously it is
> only re-armed when some data is cummulatively acknowledged (i.e.,
> SND.UNA advances), but now it is re-armed whenever RTT estimator
> is updated. This feature is particularly useful to reduce spurious
> timeout for buffer bloat including cellular carriers [1], and
> RTT estimation on reordering events.
>
> [1] "An In-depth Study of LTE: Effect of Network Protocol and
>  Application Behavior on Performance", In Proc. of SIGCOMM 2013
>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>

Acked-by: Neal Cardwell <ncardwell@google.com>

  reply	other threads:[~2013-07-22  3:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-21  5:39 [PATCH 1/4 net-next] tcp: consolidate SYNACK RTT sampling Yuchung Cheng
2013-07-21  5:39 ` [PATCH 2/4 net-next] tcp: prefer packet timing to TS-ECR for RTT Yuchung Cheng
2013-07-22  3:17   ` Neal Cardwell
2013-07-21  5:39 ` [PATCH 3/4 net-next] tcp: measure RTT from new SACK Yuchung Cheng
2013-07-22  3:32   ` Neal Cardwell
2013-07-21  5:39 ` [PATCH 4/4 net-next] tcp: use RTT from SACK for RTO Yuchung Cheng
2013-07-22  3:40   ` Neal Cardwell [this message]
2013-07-22  2:45 ` [PATCH 1/4 net-next] tcp: consolidate SYNACK RTT sampling Neal Cardwell

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