From: David Miller <davem@davemloft.net>
To: ycheng@google.com
Cc: edumazet@google.com, netdev@vger.kernel.org, ncardwell@google.com
Subject: Re: [PATCH net-next] tcp: change IPv6 flow-label upon receiving spurious retransmission
Date: Fri, 31 Aug 2018 23:03:41 -0700 (PDT) [thread overview]
Message-ID: <20180831.230341.857947500854204329.davem@davemloft.net> (raw)
In-Reply-To: <20180829215356.235336-1-ycheng@google.com>
From: Yuchung Cheng <ycheng@google.com>
Date: Wed, 29 Aug 2018 14:53:56 -0700
> Currently a Linux IPv6 TCP sender will change the flow label upon
> timeouts to potentially steer away from a data path that has gone
> bad. However this does not help if the problem is on the ACK path
> and the data path is healthy. In this case the receiver is likely
> to receive repeated spurious retransmission because the sender
> couldn't get the ACKs in time and has recurring timeouts.
>
> This patch adds another feature to mitigate this problem. It
> leverages the DSACK states in the receiver to change the flow
> label of the ACKs to speculatively re-route the ACK packets.
> In order to allow triggering on the second consecutive spurious
> RTO, the receiver changes the flow label upon sending a second
> consecutive DSACK for a sequence number below RCV.NXT.
>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied.
prev parent reply other threads:[~2018-09-01 10:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-29 21:53 [PATCH net-next] tcp: change IPv6 flow-label upon receiving spurious retransmission Yuchung Cheng
2018-09-01 6:03 ` David Miller [this message]
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