From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x22f.google.com (mail-lj1-x22f.google.com [IPv6:2a00:1450:4864:20::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 1AC403B29D for ; Tue, 14 Dec 2021 04:57:08 -0500 (EST) Received: by mail-lj1-x22f.google.com with SMTP id k23so27549254lje.1 for ; Tue, 14 Dec 2021 01:57:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=8O0349+wlmdQOfd3ZrAsb8PUCCkaWVko3V0DEfNg7ZM=; b=kJdEmoq3GwQCv/l+HgHJsnQr65/htr0LazPqyFWcHsubehILlRphx6qlAMrFaMmZdR G2aCupzdrL35bujrtZibXq93PUzeD6bZoul5cAeeF8ELsWm8Uh3PxbYUqIpOdGnsMJja S4Bx8KS3vRNIBoOdZ60SIdM/XW8U05hJcHkmnJceSXcLBmHThOqFxpn4YL14SPUJm5cw KpAjzYhEUrdEWUIvH/JM6c/Msm29qI4W1cR3heIUCqOCAQWKP2ls3pFubZjuh1VWLVoQ PM+nPr9BZjZm9WKgsED81Vep1WVs5ZMEysnlHwPkLc2vK+cZJeLAnFNgAqF26DMGFqOZ Xjhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=8O0349+wlmdQOfd3ZrAsb8PUCCkaWVko3V0DEfNg7ZM=; b=aGam3txb0TNF9Kb9Cn3NKqO/9Xt5aNKzQ+y1dO0gRBAojnb+nRPTojoBsX8mUyKYDh b4bmXAaDYwX0bNohku3LgLOP1NvdjWuP22fnAUDaPEYgbKJ2PgeZh6EFCuUiYHIKELit kjf6mhCZ3xQZv/TS4shfmaimiHlg8FqYqZHjpe6l31psaWzf16QOPJfPrcE4rZ5J6FYY ym9bdsY7InLDASe/LFPuNF2i2gG09zITNjLx0fPI58sDW1BwE5am4yBB1suSzqRkcH/F trfWpWY+CvAzwR0eFiOfLa/os4OCknY2Wwkiqf0B58fg20MzNJCBG6bUHilRZerq4LLm eWJg== X-Gm-Message-State: AOAM5306LNaw3Q8gBH19OJXknEjuTUZHLcApthpdZdemyYZNKlOHvhBv B9KTDPga08c3qdDyaMU8MNk= X-Google-Smtp-Source: ABdhPJytP0h9rMU2hUbyMKeWa5K8z9IQdJmO2LNDcTQpzh47qou0m92ous04UJT30umwhNk/H1LfaA== X-Received: by 2002:a05:651c:4c6:: with SMTP id e6mr3920795lji.411.1639475826314; Tue, 14 Dec 2021 01:57:06 -0800 (PST) Received: from smtpclient.apple (188-67-240-81.bb.dnainternet.fi. [188.67.240.81]) by smtp.gmail.com with ESMTPSA id i26sm1773540lfl.208.2021.12.14.01.57.05 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 14 Dec 2021 01:57:05 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.100.0.2.22\)) From: Jonathan Morton In-Reply-To: Date: Tue, 14 Dec 2021 11:57:04 +0200 Cc: Cake List Content-Transfer-Encoding: quoted-printable Message-Id: <89ECAB12-74A3-40B6-8C0F-D1AA22E40C71@gmail.com> References: <18098E06-CB62-4967-B604-268063392C35@gmail.com> To: Dave Taht X-Mailer: Apple Mail (2.3654.100.0.2.22) Subject: Re: [Cake] sometimes I worry about cobalt's effectiveness 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: Tue, 14 Dec 2021 09:57:08 -0000 > On 14 Dec, 2021, at 8:06 am, Dave Taht wrote: >=20 > ok, it looks like ecn and perhaps dscp is busted on this mikrotik > release. Ton more plots, false starts, and packet captures here. >=20 > https://forum.mikrotik.com/viewtopic.php?p=3D897892#p897892 >=20 > Also well, codel is doing better than cobalt, and SFQ at least at > these RTTs is doing really, really well. Codel *with ECN disabled* is doing better under these conditions, based = on what I can see via the Google Drive links. This makes some sense if = the ECN CE marks are being silently erased (which is *very* bad = behaviour), rather than the packets carrying them being treated as = dropped (as I'd expect from a wrong checksum). Under this particular pathology, COBALT is still able to act via the = BLUE algorithm, but in Cake this kicks in only when the queue first = reads as full. In other implementations of COBALT, it also triggers = when the sojourn time reaches 400ms (by default). Mikrotik - or whoever is responsible for this - needs to fix their crap = so that the ECN field is processed correctly. End of discussion. - Jonathan Morton=