From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x233.google.com (mail-lf0-x233.google.com [IPv6:2a00:1450:4010:c07::233]) (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 E2E263B2A3 for ; Fri, 24 Mar 2017 20:10:49 -0400 (EDT) Received: by mail-lf0-x233.google.com with SMTP id h125so1711947lfe.0 for ; Fri, 24 Mar 2017 17:10:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=InZjVzZYTPh0Wi7gerve8jfZoY4YepCgvEbBMW/TOoQ=; b=JGN6Q6uIo1wj4zsafI0IgJACJnzO/WhpnxJ5H2w0u4Ioy+BncRMNQRdBo/l1QRiVzS YOBqb9wX4wKHRTnMRvI09r1+gNkX8ntB6ULHj8YEgN/cECsdq3SJ4dFB/v24HR18L+EH +4EaW92YyzqVa43UHkSrCjggxk2enu8IsUiLuOX0ch8xG9odEvh7ehGBV/ejza6aU0nH m1g//+71XPRhNerrrJyGlbExecfAsRlTT9GfjNS2kFhMWMIT6nfRsqp9wQ2wUG3YD/2G d/ypEbD3V7+B/YBxJR5NCx55rUC4JXEuj3n3S4Te9FdFSiLX5tS65iggbAehK1a9PsV0 ndhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=InZjVzZYTPh0Wi7gerve8jfZoY4YepCgvEbBMW/TOoQ=; b=bLhdWfzq16MyTCCxzZ51eVVyNkBGCjK6/7YI1E/9l6O0CvfcarqccN+1fW7R2VCyN7 8rOcKfjQ7n42N9WhiXr/mS3yl1Yk7xUSv7GeRWR2/UC4sqNOCrFue7DE3LYOZGBCGH79 Nlzls8M6BB43QVJI+V7736yNqs7DqGAT+GfSnCnlKtx2Tos9nfwS+GmrXEOJNOssr+aJ HxnTG4I/pACmUNN2sHpdhzU4lMsQ3gjZBR22zn365gR9Ap+GM7t4OCAuyPzGmI03YEE9 8470TqHeAJPKNSdgZSeGI3ls5ODhxT/aFDVrvzvMU9AtJjAoX+uHOVq11IO2TvCCZD06 rUsw== X-Gm-Message-State: AFeK/H34Jloxp9r5W4sowAYQ/6iqpkOkKf/KI39NZP+gyJ7aADHNmEImOpaN7yIVhOWpKg== X-Received: by 10.25.41.11 with SMTP id p11mr5350541lfp.154.1490400648733; Fri, 24 Mar 2017 17:10:48 -0700 (PDT) Received: from [192.168.100.15] (37-219-130-28.nat.bb.dnainternet.fi. [37.219.130.28]) by smtp.gmail.com with ESMTPSA id i18sm608501lfe.16.2017.03.24.17.10.47 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 24 Mar 2017 17:10:48 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: Date: Sat, 25 Mar 2017 02:10:45 +0200 Cc: "bloat@lists.bufferbloat.net" Content-Transfer-Encoding: quoted-printable Message-Id: <09232135-222F-414A-8568-40E9BD1AF424@gmail.com> References: <1489785303.28631.318.camel@edumazet-glaptop3.roam.corp.google.com> To: xnor X-Mailer: Apple Mail (2.3124) Subject: Re: [Bloat] Inaccurate rates with HTB/HFSC+fq_codel on router due to VLAN? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Mar 2017 00:10:50 -0000 > On 24 Mar, 2017, at 20:18, xnor wrote: >=20 > you haven't responded to the cake stats I'd sent you Ah, sorry about that. I see them in the thread, but I must have missed = them at the time. You do indeed have a significant number of packet drops in each case, = with the more significant numbers corresponding to more intensive use = cases. This is reflected in the differences you quote between =E2=80=9Cin= =E2=80=9D ad =E2=80=9Cout=E2=80=9D bandwidth used; the =E2=80=9Cout=E2=80=9D= rates are all consistent with the configured rate. Importantly, you = also *don't* have any ECN-marked packets. Unfortunately, this behaviour is a known limitation of shapers operating = downstream of the actual bottleneck; they cannot control the queue as = thoroughly as they could if placed upstream of it. The problem is = sharply exacerbated when ECN is not used, since the only signalling = mechanism is then to drop packets, but every dropped packet has already = consumed time on the bottleneck link and is then not accounted for by = the shaper. You may get significantly better results from turning on ECN negotiation = on your hosts. Most servers already accept ECN negotiation, but won=E2=80= =99t initiate it. (Do we have an ECN tutorial on bufferbloat.net = already?) Your solution is an interesting one, but I have a better idea which I = could reasonably implement in Cake: account for dropped packets, as well = as delivered packets, when an =E2=80=9Cingress mode=E2=80=9D flag is = set. This avoids having an inner control loop which, I=E2=80=99ve = found, is always less accurate and takes longer to respond. I=E2=80=99d be grateful if you could open an issue on Github regarding = this =E2=80=9Cingress mode=E2=80=9D flag, as a reminder. - Jonathan Morton