From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (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 C468A3B29E; Wed, 20 Jun 2018 04:07:31 -0400 (EDT) Received: from [172.16.11.169] ([134.76.241.253]) by mail.gmx.com (mrgmx103 [212.227.17.168]) with ESMTPSA (Nemesis) id 0LtJ5T-1gBIl13U6N-012lJQ; Wed, 20 Jun 2018 10:07:20 +0200 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.4 \(3445.8.2\)) From: Sebastian Moeller In-Reply-To: <86CE2EF6-D0D2-4384-8FC0-8B7EB20D05BA@darbyshire-bryant.me.uk> Date: Wed, 20 Jun 2018 10:07:17 +0200 Cc: Jonathan Morton , "valdis.kletnieks@vt.edu" , "cerowrt-devel@lists.bufferbloat.net" , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <41B72404-6E7D-47F0-B23F-7707EA2CB87E@gmx.de> References: <1529339194.276412941@apps.rackspace.com> <1529361825.80979395@apps.rackspace.com> <145517.1529440447@turing-police.cc.vt.edu> <86CE2EF6-D0D2-4384-8FC0-8B7EB20D05BA@darbyshire-bryant.me.uk> To: Kevin Darbyshire-Bryant X-Mailer: Apple Mail (2.3445.8.2) X-Provags-ID: V03:K1:Telx0Xwhy0IYTS30Korz9Q67+BtAwxRU3bGhfdYKbFEZoDTIXUm aYlbEay6SQyi7uV6vcsn2SERVVRtiT5zI3BWzxFFEALMsG59YK8UtPr8z2qHrJkfWjZxPc+ NuPdiSKDgyT0xrWSyC2AMDb0oHKTzSndz4OAsYyKARAZ57lhgy7FBI03n/W4oC0lUcEjq5A AWYdMjW5EpQ32MbxT1/WQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:M0rvuTmp1AI=:7pNMYjPfXo1dUqOnYpW00E DlbIaKawW9T9bTbXCT/mHTYhxtn7bvhSaCK92KABx97T1po3ijOkEDjdcOLlCorg1zU58YLbZ 9siPnU9lUuVowcoyvWIU1HSeBb2ryx/FrXwcJKqe+bKhHC5IbXRJh9RlNLNPfC3HEjDroPVDv n4FEjXb2H/HDhENnwwVnd9B2GZrn/kC3W0fPZvwXD5LVbLw8Mv+4R6QuhZUn5+u3v6p5Q7zKD I+mmY/+OKzcNHUBuh3YsVh0iHeLqI/umIQqPw8LhWYZvskBkj8lMnxOyqz+ymProwrJmMxwp5 ipT0DFwW4eLNmtUQLxNwTG6vTNKsGwFqrRcJJaIW5B9cd33lUai3xGDN3Fnbc/3j/OzI7tB0E ZIfVwKDTybThIYIePjyQ7R7H25j9dBKqf2yRvsBXFMdAhqMfuOItw0lvWNHrVGU30SEf/3OD7 368bgOr8SX5qNJWAR10ERTQw9JpyudQpWyF7ZWC4rqHItHud1TNMKwRf9f/M12sVzSh/ipOzi 1HZfJu35JjGhHMfF1Fu3w7Lav3A5I3SLO7ZTBA366ePeCWSb29cn3Crv71DnPlKapca5xssL6 5QMWTuhh86ywTQGqYbvx43f8ScTBi2QJS92kgnNYBYy4KLPXnHkxzNKJtjhG+4siThSwG3Dkp Dl0G8HAAzhu7ECUtf2OZI59UEJaThT77XOotv3vECGuQaWcYK9xA3el3ZRycnjvMdxbNTVszg aHqYN48j7HJ/4gH2kLW6O7WEoFO2MmfFjGCTtX6JggXpwtfHGtNnsyo8Z0RWKOXvTo0VZ2fyt j3vmUsc Subject: Re: [Bloat] [Cerowrt-devel] Invisibility of bufferbloat and its remedies 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: Wed, 20 Jun 2018 08:07:32 -0000 Hi Kevin, > On Jun 20, 2018, at 09:12, Kevin Darbyshire-Bryant = wrote: >=20 >=20 >=20 >> On 20 Jun 2018, at 00:41, Jonathan Morton = wrote: >>=20 >>> On 19 Jun, 2018, at 11:34 pm, valdis.kletnieks@vt.edu wrote: >>>=20 >>> Do we have a good cookbook on how to determine the set-rate? >>=20 >> On DSL, the sync rates in each direction should usually be readable = from the modem; they are typically reported on the router's status page. = The advertised rate is less reliable, to say the least. >=20 > I=E2=80=99ve been experimenting with this hack in sqm-scripts to do = just that = https://github.com/ldir-EDB0/sqm-scripts/commit/a71ab1c9acd75d6e9254360e83= 2ac7b6f9514e88 originally on my parents DGN3500 and currently on my on = BT HomeHub5a test line. Clever (I see how you chiseled data_rates() into shape here, = respect)! Even though I believe that this is not pppoa specific and = should probably check whether /lib/functions/lantiq_dsl.sh exists. = Actually this code will also work on VDSL2 links... (and we should also = be able to extract the encapsulation atm or ptm). if [ "pppoa-wan" =3D "$IFACE" ]; then if [ -f "/lib/functions/lantiq_dsl.sh" ] : then ... fi fi But would it not be simpler to call /etc/init.d/dsl_control status | = grep -e "Data Rate:" or somesuch? Cureently openwrt only supports = lantiq/intel modems, but if broadcom modems should ever be supported I = venture a guess they will not use /lib/functions/lantiq_dsl.sh to = generate the stats output ;) (not that there is a guarantee that = dsl_control would exost and generate compatible output). But I believe that this is not that helpful as a mode to automatically = set the bandwidth*, as I assume that most ISPs will shape the downstream = bandwidth upstream of the DSLAM (if just to avoid having a DDOS against = one user taking down the whole DSLAM). In my case my ISP even shapes the = upstream, which is somewhat more puzzling. It looks like a cool way to = deal with variable sync (either after a re-sync due to say DLM action or = due to SRA) so how about polishing this a bit and including this as pure = informational line in the log?=20 *) if this is to be made automatic by say allowing to scrape bandwidth = from the modem we would need additional setting for setting the shaper = percentage. I wonder whether all of this is worth it though, given that = the number of users running sqm on devices in control of the dsl-modem = is going to be miniscule, no? >=20 > It fails to work if the ISP does rate banding (BT 20CN does this, BT = 21CN doesn=E2=80=99t) where downstream is limited to a rate below = downstream sync rate. I guess a lookup table could be implemented. I predict that a lookup table is going to be constantly out of = date, especially since at least my ISP is a moving target in both the = shaper settings as well as the actual overheads (on the plus side they = started to send the applicable net bandwidth as part of the pppoe = negotiations (but failed to document how those rates are actually to be = interpreted ;) win some loose some)).=20 Final thought, how about just using this on the luci side to give hints = about the sync bandwidth in the GUI (like displaying the value of either = sync for xdsl or the speed for ethernet devices (speed in ethtool = parlance, so 10Mb/s, 100Mb/s, ...)) that will not be as smooth as your = solution, but should also be more robust against doing the wrmg thing = automatically? Or am I overcomplicating things again. Final final thought ;) since lantig_dsl.sh is quite openwrt specific, = maybe we should do the automatic mode inside of the equally openwrt = specific /usr/lib/sqm/run instead of in start-sqm that will might also = be executed on other platforms? Best Regards Sebastian >=20 > Kevin > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat