From: Rick Jones <rick.jones2@hp.com>
To: Saku Ytti <saku@ytti.fi>
Cc: netdev@vger.kernel.org
Subject: Re: TCP and reordering
Date: Tue, 27 Nov 2012 09:05:30 -0800 [thread overview]
Message-ID: <50B4F2DA.8020206@hp.com> (raw)
In-Reply-To: <CAAeewD8zsfb6QPFecvPab_oK3D3T7eG_M53MVvfJ2QrxUFxWSQ@mail.gmail.com>
On 11/27/2012 01:32 AM, Saku Ytti wrote:
> Today due to fast retransmit performance on links which cause
> reordering is appalling.
>
> Is it too esoteric situation to handle gracefully? Couldn't we
> maintain 'reorder' counter in socket, which is increment when we get
> two copies of same packet after duplicate ack, if this counter is
> sufficiently high in relation to packet loss, we could start delaying
> duplicate acks as we'd expect to receive the sequence very soon.
Packet reordering is supposed to be the exception, not the rule. Links
which habitually/constantly introduce reordering are, in my opinion,
broken. Optimizing for them would be optimizing an error case.
That said, there is net.ipv4.tcp_reordering which you can increase from
the default of three to desensitize TCP to such broken links. That will
though be on the sending rather than receiving side.
rick jones
next prev parent reply other threads:[~2012-11-27 17:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-27 9:32 TCP and reordering Saku Ytti
2012-11-27 17:05 ` Rick Jones [this message]
2012-11-27 17:15 ` Saku Ytti
2012-11-27 18:00 ` Rick Jones
2012-11-28 2:06 ` David Miller
2012-11-28 7:26 ` Saku Ytti
2012-11-28 8:35 ` Vijay Subramanian
2012-11-28 8:54 ` Saku Ytti
2012-11-28 18:24 ` Rick Jones
2012-11-28 18:33 ` Eric Dumazet
2012-11-28 18:52 ` Vijay Subramanian
2012-11-28 18:44 ` Saku Ytti
2012-11-28 7:59 ` David Woodhouse
2012-11-28 8:21 ` Christoph Paasch
2012-11-28 8:22 ` Vijay Subramanian
2012-11-28 9:08 ` David Woodhouse
2012-11-28 11:02 ` Eric Dumazet
2012-11-28 11:49 ` David Woodhouse
2012-11-28 12:26 ` Eric Dumazet
2012-11-28 12:39 ` David Woodhouse
2012-11-28 12:52 ` Eric Dumazet
2012-11-28 15:47 ` David Woodhouse
2012-11-28 16:09 ` Eric Dumazet
2012-11-28 16:21 ` David Woodhouse
2012-11-28 16:19 ` Benjamin LaHaise
2012-11-28 16:41 ` David Woodhouse
2012-11-28 17:08 ` Benjamin LaHaise
2012-11-28 17:16 ` Eric Dumazet
2012-11-28 18:01 ` David Woodhouse
2012-11-29 15:10 ` Noel Grandin
2012-12-02 1:30 ` David Woodhouse
2012-12-02 2:40 ` Eric Dumazet
2012-12-02 9:31 ` David Woodhouse
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