From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (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 DFFEE3B2A4 for ; Wed, 24 Jun 2020 10:40:07 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1593009606; bh=de0b9vS9f7KhuPqm8guURm9rbo9HQyZLKiUn1bpuuE8=; h=X-UI-Sender-Class:Subject:From:In-Reply-To:Date:Cc:References:To; b=INXx/zoITARTJ0XtGyu9Hjt25DxOiNupDpDq2vDNzdcBqs3eIy6in8ojQX/l7GF1M vSCHVWQF4lx1x+N1fnDToHHalnC8TpVF/j9Cq1Hj5GLFw0seW1ZReeQ4JibawvDHIO 3jtgqxmO5s/ONxkFM17vF9TBcM9X0L5+DlpScxMI= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [192.168.250.102] ([134.76.241.253]) by mail.gmx.com (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MFsUv-1jdMwT068t-00HP3D; Wed, 24 Jun 2020 16:40:06 +0200 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) From: Sebastian Moeller In-Reply-To: <8ABBBE20-5045-41CF-967A-CD8961400ABE@darbyshire-bryant.me.uk> Date: Wed, 24 Jun 2020 16:40:05 +0200 Cc: Cake List Content-Transfer-Encoding: quoted-printable Message-Id: <1A34E9D8-C6FD-4E09-866F-DB30F73D6ABC@gmx.de> References: <8ABBBE20-5045-41CF-967A-CD8961400ABE@darbyshire-bryant.me.uk> To: Kevin Darbyshire-Bryant X-Mailer: Apple Mail (2.3445.104.14) X-Provags-ID: V03:K1:/YzK40rKSiJ5pONXCc2tUoarHGgd0wn9ynvPvYq7Sh7ONY/ub/v MHf/IfyQspy5NRnDEzUxe3WKO+5ltsJPYrlmc1JHiFaLCshjNPty6Q+O5ZAtKQ4piNQY8tm jYEOSd148nJnECR3+5wmgOk1LRF1DzbBM59jJdii7+31WcHfpHz7wKvxbmVPAde1AWHko0W csfNtG7C8oSI+c4X2qAAg== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:9HCuIlfNG5o=:1U7+T1T1mKgX4ZhUlW9Nrm VHhu5Ch1fdMrS7KjDRDSqhsO1F3fHYmIZl6ZJtL6Mq9+dgK5HbcMriBIHNWioXosHbWSycvQ7 kNWI68AFmOLTLEllw7nCmSd0Z9cxrvb1B9CQqn4185BNfUNo+Zrx/Orl/ooxcVLQzgM9cWlGb pY448ymk9UMGhPS0zQyf0Hu4p7rUgAVw3GFkEgWlvUjjKu3BJaAqZ/jPHoLS8qh3P1s+cAI4f 0NQ5qcJyP5S5PHbiJkHTQL3EkBzRMi+7bWi/1p4ipOjQWP5ZBwLRzcxj5uIBERQTpGG8VU1Jk hDkFxfNpmBI8M0DM07xSst6hmfXpRZC5+CskHNV4t/lnGEzTXf9WXoi/BiU8dfpJC6z6pK5ES qn28BjWZWiG3gU2KTt8PSB/AMc7/PtOa6kvtrLwhADRDCFxWU/kBJbUGy4wNIxs5+sXifhlHS 80fy8LQ1LxqV7qoBYWm31immQFtpGxwojaNEGfKvYw1Iaympt7F5V6S5PwKrqH9wwE4ecnxcG zFtlW29RGuLQNTfyDZVzFeYrcfgH47+p27PWunQ7EL7KtFvu9kdD5P3NKALXppyp85csBDaRu s4KefhRV5cKYyFLgIFrvaJOLk1QnVQPQ/zjopuRUUZv/LCxKUlcSUJ/N0GIgM66DU5XnN6MeF sXZnxkGbaP+7kkb0ruhPM4xXVk0y1WvFOoNACwtX0tYBsBEez4Iysk+JkPl0IwtXwXFfqQ4DD epEYyWuFvqN8syKuDCoROwT8M518UmQL9CTW48pBYZ+iv2JuBrEi/vpOjKzyY9FSVuy8pwpo1 WyeZUxHzdb4qXP2BDahGLExhkmBnpiFJ5i68UrAZ/q28xEUBbWXR5NBn+9wTzeFHyg13nCQJ7 kwwn7jllFoEaX56ic78bTleKEum/F1ZOdqJ8UJqlf0KqlKI7MCzSuddDjbw8uKl8VvBMc5PnD s0Gx+Mg03i10pxv679dgOjJVRzcA4TtSgsZuF+WKkME1G7C5xU34Cy5sL0k4DMzP2ecP8b0Pj hr1oXiSEuq1mCn7PDR73uzvm9ChOVIofeKpXwArAlR7j+YgDvI79MXkeP9DfBpYy/cCMbZd5s 2dQfUwaRT3ld294T/DaXB8kkKF67f/taydxbpk/ELPzhcIO9ZEL7eujv8XuhuJEhD7n10cXlW RXDirgSonyrf/bipbTGbqfCD8oQnJrBLHDdXpSU5FlMN2lMxO2ALcoxDb7H2RzStiqNfA= 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: Wed, 24 Jun 2020 14:40:08 -0000 Hi Kevin, 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 ;) Best Regards Sebastian > On Jun 24, 2020, at 16:33, Kevin Darbyshire-Bryant = wrote: >=20 > Genuine question. For the reduced bandwidth tins in diffserv3/4/8 a = different rate and hence different target & interval values are also = calculated. I get why a target/interval calculation is desirable for = the =E2=80=98main=E2=80=99 tin - this forms a =E2=80=98best case=E2=80=99 = of how long each byte takes to transmit and is fundamental to the = shaper. What I=E2=80=99m less clear on is why increased targets & = intervals are used for the reduced threshold tins. >=20 > To my mind it means those tins can be more =E2=80=98bursty=E2=80=99 = before codel jumps on them. That=E2=80=99s possibly ok on an egress = path but I=E2=80=99m not so convinced on an ingress path. >=20 > Please point out the error in my thinking! >=20 >=20 > Cheers, >=20 > Kevin D-B >=20 > gpg: 012C ACB2 28C6 C53E 9775 9123 B3A2 389B 9DE2 334A >=20 > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake