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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: David Miller <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	Yuchung Cheng <ycheng@google.com>,
	Neal Cardwell <ncardwell@google.com>,
	Tom Herbert <therbert@google.com>,
	Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH net-next] tcp: introduce TCPSpuriousRtxHostQueues SNMP counter
Date: Thu, 18 Apr 2013 11:06:21 -0700	[thread overview]
Message-ID: <1366308381.3205.66.camel@edumazet-glaptop> (raw)
In-Reply-To: <20130418104510.3624457a@nehalam.linuxnetplumber.net>

On Thu, 2013-04-18 at 10:45 -0700, Stephen Hemminger wrote:
> On Thu, 18 Apr 2013 09:52:51 -0700
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
> 
> > From: Eric Dumazet <edumazet@google.com>
> > 
> > Host queues (Qdisc + NIC) can hold packets so long that TCP can
> > eventually retransmit a packet before the first transmit even left
> > the host.
> 
> I though you were use fq_codel ;-) and that wouldn't happen.

Remind that fq_codel drops packets at dequeue time only ;)

So TCP stack could retransmit while prior packet is still in fq_codel
queue.

  reply	other threads:[~2013-04-18 18:06 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-18 16:52 [PATCH net-next] tcp: introduce TCPSpuriousRtxHostQueues SNMP counter Eric Dumazet
2013-04-18 17:45 ` Stephen Hemminger
2013-04-18 18:06   ` Eric Dumazet [this message]
2013-04-18 18:19     ` Hagen Paul Pfeifer
2013-04-18 19:29       ` Eric Dumazet
2013-04-18 19:54         ` Yuchung Cheng
2013-04-18 20:26         ` Hagen Paul Pfeifer
2013-04-18 18:57 ` David Miller

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