From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from EUR04-DB3-obe.outbound.protection.outlook.com (mail-eopbgr60055.outbound.protection.outlook.com [40.107.6.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id EBE5D3B29D for ; Thu, 25 Jun 2020 09:40:32 -0400 (EDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=R+fIAEEoIuMwJiZfkIsqiUbtoMmELsDBIwOiSAQ7b0WI31iNzni2YH3OAWhXvfkyzHdirJ7XLLbKGOQy/znnhToLWhYS5aPphY8E8DTuVRoSo6OdUcSQT44RftZWyBeIYEx73tR9/7KFtMmI7hQudx5bcpETYSnfmR8RJ06Rc4rWQhjZaUXgdTQ1IlToDpXGUcDa3jyDTFgkiZEdVWUGYL3hHXvEkmS4ZJeMd51jsK7XpD2DucPDYDrOA0HiMCCu5yE8u3PJS1qBd76AvNPrz3lbe4A9VIUcwoh0+T2tI4+JT0eR034KMf0Qn0cgP6GWkmfpzMjt7zSmmHTgAoXJzQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ayQwtk4sAuHm/Lz6CrBSuxg/rwDJ+SieGaoTMq8Ujyo=; b=mhxWvKOMdVMh/iycG8jW1Ha3l3siWQcbKSHTR7z2brEInnscFqvE/L8hxCSVPlhCpWmb/FQmwN1xF/bgXyfLdHyt/nh+IwLL0wM6LTuga0eLzlKr2dT93JvHEZ5wSLeViQ/+pBeO1FeFOPg41VFuMkxSBlucBqRqfvTmp2iBIGapAGljmy2i/OGcHS+RWxBVfdsyjXJD308rS2WyMG+pa5F785pecvlqKDOZLyb0glQSvdRRzxwyYmZPG//GFh7OMElQS/W/ClkzAnmeTiqUVBoEPpwyVnSOj2vIoncW2ETr5nxpN0BqoMJVhxZsDxEiKthBhrXQw3WSSBDopa6vtA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=darbyshire-bryant.me.uk; dmarc=pass action=none header.from=darbyshire-bryant.me.uk; dkim=pass header.d=darbyshire-bryant.me.uk; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=darbyshire-bryant.me.uk; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ayQwtk4sAuHm/Lz6CrBSuxg/rwDJ+SieGaoTMq8Ujyo=; b=hVUQMeiLoOpxuc2bwQOG8XNe48iWhBCqx+GL7pr+EPIA2CJxoGmfDwUQzXc90OJsUWH8N1rGCgpBYjhr1YxPvn6USokV5qrs3QXvLA1guzfhGMhqM+K3xAOMWu90/8NsycNaR+l5xhgZbBlokD92wgls7AMyfPdkfyVEd71d1Ro= Received: from VI1PR03MB4575.eurprd03.prod.outlook.com (2603:10a6:803:59::12) by VE1PR03MB6045.eurprd03.prod.outlook.com (2603:10a6:803:112::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3131.21; Thu, 25 Jun 2020 13:40:31 +0000 Received: from VI1PR03MB4575.eurprd03.prod.outlook.com ([fe80::dcff:4b45:98e6:d823]) by VI1PR03MB4575.eurprd03.prod.outlook.com ([fe80::dcff:4b45:98e6:d823%3]) with mapi id 15.20.3131.021; Thu, 25 Jun 2020 13:40:30 +0000 From: Kevin Darbyshire-Bryant To: Sebastian Moeller CC: Cake List Thread-Topic: [Cake] Why are target & interval increased on the reduced bandwidth tins? Thread-Index: AQHWSjRzmOyqmANMDkGEJHIRIZfZaKjn1kqAgAGBroA= Date: Thu, 25 Jun 2020 13:40:30 +0000 Message-ID: References: <8ABBBE20-5045-41CF-967A-CD8961400ABE@darbyshire-bryant.me.uk> <1A34E9D8-C6FD-4E09-866F-DB30F73D6ABC@gmx.de> In-Reply-To: <1A34E9D8-C6FD-4E09-866F-DB30F73D6ABC@gmx.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: yes X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3608.80.23.2.2) authentication-results: gmx.de; dkim=none (message not signed) header.d=none;gmx.de; dmarc=none action=none header.from=darbyshire-bryant.me.uk; x-originating-ip: [2a02:c7f:1227:c00::dc83] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 8f27115b-e368-4c5c-0f1f-08d8190d5419 x-ms-traffictypediagnostic: VE1PR03MB6045: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0445A82F82 x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: jF07dtUbThAqdD7SMcNj152WE3fPsIusNCIfj5Ps3oYjid3lov5FRegnZLJpjM345GrE9kf4hF6CxfCmqB2uRXEqFOJ8qRU7TSHkDFK0G5FnnhzPZ9BjQlGXDnhsrKcI9lHdXw24KFAzm5oGK7qYrmWQlZiX4474WtCS7omvnhx/wYI/7Q4Ne1Uet7MQ1ApmSZdt2+aHfHLLrgW2uthywj8fUzQNkJ8kM+wnJpungFiCRqJtlBJM5U9VuMxN4p5rUm8xP9tUVfYtN3dh5UYJy9i/7USIRhK0wXNRaINnRTXNZqBUE5uHHcIEG88sVP68XqZj/LR6qNCTEdMnm1f42dRM4a0l6bfjE/uXtKQ5VBX/YtvouLTmgctP+Fc+5qCt x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:VI1PR03MB4575.eurprd03.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(346002)(396003)(39830400003)(376002)(136003)(366004)(36756003)(53546011)(91956017)(71200400001)(5660300002)(186003)(8936002)(83380400001)(2906002)(76116006)(8676002)(66946007)(99936003)(64756008)(6512007)(33656002)(66446008)(66476007)(66556008)(316002)(66616009)(6916009)(6486002)(2616005)(4326008)(6506007)(508600001)(86362001)(3903001); DIR:OUT; SFP:1101; x-ms-exchange-antispam-messagedata: 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 x-ms-exchange-transport-forked: True Content-Type: multipart/signed; boundary="Apple-Mail=_F9965210-46AE-4F10-B29E-727207EC73D1"; protocol="application/pgp-signature"; micalg=pgp-sha256 MIME-Version: 1.0 X-OriginatorOrg: darbyshire-bryant.me.uk X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: VI1PR03MB4575.eurprd03.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8f27115b-e368-4c5c-0f1f-08d8190d5419 X-MS-Exchange-CrossTenant-originalarrivaltime: 25 Jun 2020 13:40:30.7303 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 9151708b-c553-406f-8e56-694f435154a4 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: LomD0VY0BWur2r268UpNTJwcLXYRngJjElWXY0l9u1vMmEFG6AKelbSLSRzpb8HHx3LheG8wZKwVWsvrBYhQcy+LOAzrxeauFrTBeUhI/Bg= X-MS-Exchange-Transport-CrossTenantHeadersStamped: VE1PR03MB6045 Subject: Re: [Cake] Why are target & interval increased on the reduced bandwidth tins? X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Jun 2020 13:40:33 -0000 --Apple-Mail=_F9965210-46AE-4F10-B29E-727207EC73D1 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On 24 Jun 2020, at 15:40, Sebastian Moeller wrote: >=20 > Hi Kevin, >=20 > so the way codel is designed target is best understood as a function = of interval (allowing 5-10% of interval as standing queue allows a fine = trade-off between bandwidth utilization and latency under load = increase). > Now, interval is basically akin to the time you are willing to give a = flow to react to signals, it should be in the same order of magnitude as = the path RTT. Now reducing the bandwidth allocation for a traffic class = will increase its saturation load RTT and hence increasing the target = seems justified; target just follows along due to still wanting a = reasonable bandwidth/latency trade-off. > So in short these scale the shaper to work well under loaded = conditions. But Jonathan & Toke will be able to give the real = explanation ;) >=20 > Best Regards > Sebastian So crudely interval is the delay before we start jumping on packets. = And I think that=E2=80=99s the wrong thing to do for ingress. So the = scenario I have in my head says that BK traffic could burst at full = bandwidth rate (or higher) filling upstream ISP buffers and thus = inducing delays on all other traffic because "we think it=E2=80=99s a = slow link and have high interval and target values=E2=80=9D delaying our = response to the burst. Whereas if we retain the default interval & = target from the true link capacity calculation we=E2=80=99ll jump on it = in time. The same thing happens in traditional egress mode but it doesn=E2=80=99t = matter as much as we are in control of our own buffer/queue and we=E2=80=99= ll see the higher priority traffic and skip to servicing that and = gradually bring the BK tin back under control. What=E2=80=99s the error in my thinking? Kevin --Apple-Mail=_F9965210-46AE-4F10-B29E-727207EC73D1 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEASyssijGxT6XdZEjs6I4m53iM0oFAl70qU0ACgkQs6I4m53i M0p9ChAA2B0lbXv+ntrw8hmq8oZKSa3n7A+5/3RvmdXiJ5KlCr6mw05HrM1tp4YU Hghf4m3kcWmQ4yuVl0fkVuTeqWrIx66CgLwvGU6jxSsWb4UcfUE3DDEn30Ufpu20 CHxKmpQi6onZnxONqHIZ+y+OZilCdV+ETKqDTtcN6W16mxGy+Ztib1AT3gSM8BtH 0s2OakzlmFXDRhdUPAKQsE/3OZMpGi/zi9m4js2utJSpzkkFtUZ5Sz/+4kImE2Fi p5Ta+sSUohfv1UTkuMh3VnwlBMZjZzx6Ztbdqv1X1iJGsAxwzi70qcQsgejUawJJ PCLXHTPPmxxdcYxJ9EsSAK5o//0MYKnsZ4OgK6BtuA/HZXLjNvtoCw5QCBHjUnNC tudeoZvvZ8hlEIVvwFf+LFjs6OznVii3ouMOOqN76xzSksuIMNO5f1XBVDtrOoUr pFx3yAWXbBBuubiWqDe7ebRaPotxo2TLjHqSnWl+27XLFvBAg+OkT2/mUEZANoOx qP+xpzANcM8CgZJ0Ev+V+WjuCZ3Avmrlx4MG4QpI9GFy6sQiKsE4Bq3oYukNmZ3n saDdU6x/HrPPNa9OtGYoEOQ1RnBf3DfVtC0c45hgIWPWJmvsVGBqDy2kJl8TizTV bDbbljbiV4wnE7ctvHWsowPQjkeXNEvCewqMxuQVRLUxDy8gUhI= =ZFNG -----END PGP SIGNATURE----- --Apple-Mail=_F9965210-46AE-4F10-B29E-727207EC73D1--