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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Nandita Dukkipati <nanditad@google.com>
Cc: netdev <netdev@vger.kernel.org>,
	Yuchung Cheng <ycheng@google.com>,
	codel@lists.bufferbloat.net, Matt Mathis <mattmathis@google.com>,
	Neal Cardwell <ncardwell@google.com>,
	David Miller <davem@davemloft.net>
Subject: Re: [Codel] [PATCH net-next] fq_codel: report congestion notification at enqueue time
Date: Fri, 29 Jun 2012 06:18:59 +0200	[thread overview]
Message-ID: <1340943539.13187.193.camel@edumazet-glaptop> (raw)
In-Reply-To: <CAB_+Fg7x2pV72Wa45QLuokHTVPuzdmrMfwiuLjS_vi02vtasAA@mail.gmail.com>

On Thu, 2012-06-28 at 16:52 -0700, Nandita Dukkipati wrote:
> As you know I really like this idea. My main concern is that the same
> packet could cause TCP to reduce cwnd twice within an RTT - first on
> enqueue and then if this packet is ECN marked on dequeue. I don't
> think this is the desired behavior. Can we avoid it?

I'll work on this.

In my experiences, I found that no drops (or ECN marks) were done at
dequeue time once one NET_XMIT_CN was returned, but its certainly
possible if other flows compete with this one.

Strangely, SFQ has the same behavior and nobody complained yet ;)

Thanks



  reply	other threads:[~2012-06-29  4:19 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-28 17:07 Eric Dumazet
2012-06-28 17:51 ` Dave Taht
2012-06-28 18:12   ` Eric Dumazet
2012-06-28 22:56     ` Yuchung Cheng
2012-06-28 23:47       ` Dave Taht
2012-06-29  4:50         ` Eric Dumazet
2012-06-29  5:24           ` Dave Taht
2012-07-04 10:11           ` [Codel] [RFC PATCH] tcp: limit data skbs in qdisc layer Eric Dumazet
2012-07-09  7:08             ` David Miller
2012-07-09  8:03               ` Eric Dumazet
2012-07-09  8:48                 ` Eric Dumazet
2012-07-09 14:55               ` Eric Dumazet
2012-07-10 13:28                 ` Lin Ming
2012-07-10 15:13                 ` [Codel] [RFC PATCH v2] tcp: TCP Small Queues Eric Dumazet
2012-07-10 17:06                   ` Eric Dumazet
2012-07-10 17:37                   ` Yuchung Cheng
2012-07-10 18:32                     ` Eric Dumazet
2012-07-11 15:11                   ` Eric Dumazet
2012-07-11 15:16                     ` Ben Greear
2012-07-11 15:25                       ` Eric Dumazet
2012-07-11 15:43                         ` Ben Greear
2012-07-11 15:54                           ` Eric Dumazet
2012-07-11 16:03                             ` Ben Greear
2012-07-11 18:23                     ` Rick Jones
2012-07-11 23:38                       ` Eric Dumazet
2012-07-11 18:44                     ` Rick Jones
2012-07-11 23:49                       ` Eric Dumazet
2012-07-12  7:34                         ` Eric Dumazet
2012-07-12  7:37                           ` David Miller
2012-07-12  7:51                             ` Eric Dumazet
2012-07-12 14:55                               ` Tom Herbert
2012-07-12 13:33                   ` John Heffner
2012-07-12 13:46                     ` Eric Dumazet
2012-07-12 16:44                       ` John Heffner
2012-07-12 16:54                         ` Jim Gettys
2012-06-28 23:52 ` [Codel] [PATCH net-next] fq_codel: report congestion notification at enqueue time Nandita Dukkipati
2012-06-29  4:18   ` Eric Dumazet [this message]
2012-06-29  4:53 ` Eric Dumazet
2012-06-29  5:12   ` David Miller
2012-06-29  5:24     ` Eric Dumazet
2012-06-29  5:29       ` David Miller
2012-06-29  5:50         ` Eric Dumazet
2012-06-29  7:53           ` David Miller
2012-06-29  8:04           ` David Miller

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