From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <toke@toke.dk>
Received: from mail.toke.dk (mail.toke.dk [52.28.52.200])
 (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.bufferbloat.net (Postfix) with ESMTPS id 07D293CB39
 for <cake@lists.bufferbloat.net>; Thu, 17 May 2018 09:11:38 -0400 (EDT)
From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023;
 t=1526562692; bh=2tdqXyfSLer3alYtFHrpD+vV/qDj6j0Iu4AXZvjaKtU=;
 h=From:To:Cc:Subject:In-Reply-To:References:Date:From;
 b=qCwGiEgH9ip/NFfxDe2tAesOR1eRbmm75uH7XfU6c1QFA3nRFQ/mn5gkcXKypeNra
 I4FLPkmg8bRn9hqE7pw7+RCuyOp23TLtKinSBTQJPF3JsC3ZVw3809B6WJZ42si66q
 saw8PpNeAfkCetKCf2Jnt5uTnYeUAucMVYqczu76zh6zQxoz42fy014X+n6g0On9QJ
 oAqGPdW6TEnHBxwMp9CjsqJ0q8B2cv4zs/H5kuf+iTmfWjII0eAHrcvPEVB0kuQP+8
 pMREzVD8oNBqk2gUZYQYBEQ9AkXbrmj7GdV3sFxXKQ1v5AVguCmT8AM1fJhrVVpgDG
 WtE7fy/setO4g==
To: Eric Dumazet <eric.dumazet@gmail.com>, netdev@vger.kernel.org
Cc: cake@lists.bufferbloat.net
In-Reply-To: <541d62af-3938-5fdc-666c-dd243fa465b5@gmail.com>
References: <152650253056.25701.10138252969621361651.stgit@alrua-kau>
 <152650254614.25701.1377066681230937234.stgit@alrua-kau>
 <a002ff7b-2606-afcd-1769-b216f4db428c@gmail.com> <87in7my196.fsf@toke.dk>
 <541d62af-3938-5fdc-666c-dd243fa465b5@gmail.com>
Date: Thu, 17 May 2018 15:11:31 +0200
X-Clacks-Overhead: GNU Terry Pratchett
Message-ID: <877eo2xw8s.fsf@toke.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Cake] [PATCH net-next v12 3/7] sch_cake: Add optional ACK
	filter
X-BeenThere: cake@lists.bufferbloat.net
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: Cake - FQ_codel the next generation <cake.lists.bufferbloat.net>
List-Unsubscribe: <https://lists.bufferbloat.net/options/cake>,
 <mailto:cake-request@lists.bufferbloat.net?subject=unsubscribe>
List-Archive: <https://lists.bufferbloat.net/pipermail/cake>
List-Post: <mailto:cake@lists.bufferbloat.net>
List-Help: <mailto:cake-request@lists.bufferbloat.net?subject=help>
List-Subscribe: <https://lists.bufferbloat.net/listinfo/cake>,
 <mailto:cake-request@lists.bufferbloat.net?subject=subscribe>
X-List-Received-Date: Thu, 17 May 2018 13:11:39 -0000

Eric Dumazet <eric.dumazet@gmail.com> writes:

> On 05/17/2018 04:23 AM, Toke H=C3=B8iland-J=C3=B8rgensen wrote:
>
>>=20
>> We don't do full parsing of SACKs, no; we were trying to keep things
>> simple... We do detect the presence of SACK options, though, and the
>> presence of SACK options on an ACK will make previous ACKs be considered
>> redundant.
>>=20
>
> But they are not redundant in some cases, particularly when reorders
> happen in the network.

Huh. I was under the impression that SACKs were basically cumulative
until cleared.

I.e., in packet sequence ABCDE where B and D are lost, C would have
SACK(B) and E would have SACK(B,D). Are you saying that E would only
have SACK(D)?

-Toke