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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Dave Taht <dave.taht@gmail.com>
Cc: Nandita Dukkipati <nanditad@google.com>,
	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: [PATCH net-next] fq_codel: report congestion notification at enqueue time
Date: Fri, 29 Jun 2012 06:50:57 +0200	[thread overview]
Message-ID: <1340945457.29822.7.camel@edumazet-glaptop> (raw)
In-Reply-To: <CAA93jw7ywd0auqN=k2J4fLOGYMLRH+agWr4P+_CisgvRtvgJUw@mail.gmail.com>

On Thu, 2012-06-28 at 19:47 -0400, Dave Taht wrote: 
> On Thu, Jun 28, 2012 at 6:56 PM, Yuchung Cheng <ycheng@google.com> wrote:
> > On Thu, Jun 28, 2012 at 11:12 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> >> On Thu, 2012-06-28 at 10:51 -0700, Dave Taht wrote:
> >>
> >>> clever idea. A problem is there are other forms of network traffic on
> >>> a link, and this is punishing a single tcp
> > Dave: it won't just punish a single TCP, all protocols that react to
> > XMIT_CN will share similar fate.
> 
> What protocols in the kernel do and don't? was the crux of this question.
> 

AFAIK that only tcp cares a bit, or seems to.

But not that much, since it continues to send packets.

Thats because tcp_transmit_skb() changes the NET_XMIT_CN status to plain
NET_XMIT_SUCCESS.

My long term plan is to reduce number of skbs queued in Qdisc for TCP
stack, to reduce RTT (removing the artificial RTT bias because of local
queues)

> I'm not objecting to the idea, it's clever, as I said. I'm thinking I'll
> apply it to cerowrt's next build and see what happens, if this
> will apply against 3.3. Or maybe the ns3 model. Or both.

A router will have no use of this feature, not sure you need to spend
time trying this ;)

  reply	other threads:[~2012-06-29  4:50 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-28 17:07 [PATCH net-next] fq_codel: report congestion notification at enqueue time 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 [this message]
2012-06-29  5:24           ` Dave Taht
2012-07-04 10:11           ` [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                 ` [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 ` [PATCH net-next] fq_codel: report congestion notification at enqueue time Nandita Dukkipati
2012-06-29  4:18   ` Eric Dumazet
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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