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 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 9F31F21F4E7 for ; Tue, 3 Nov 2015 00:20:51 -0800 (PST) Received: from u-089-d061.biologie.uni-tuebingen.de ([134.2.89.61]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0MNMyz-1ZnDIg33Cz-006smq; Tue, 03 Nov 2015 09:20:43 +0100 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Sebastian Moeller In-Reply-To: Date: Tue, 3 Nov 2015 09:20:40 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <87pozspckj.fsf@toke.dk> <6A2609D9-7747-487B-9484-ECC69C50DE96@gmx.de> To: Jonathan Morton X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:f3CIvgAA3WkqWxc8YUQtuCO5w8MJN5s0yn8OnKO2FdgzKg1r1GJ HH/UB1Dw8ABBcacV2zjXXF0Y47gC7fXAahxEVzrHn56lbDg5G4YEkx3nO9NJ2/pTRWoay/X 2FUc8slBQjA59WKKrnGaqrZml3mTThxgmBM/x/9AZd2LPtGs3TncSdfG1s0BVxs4L0mQKkS 7FODR89keOYeJLdDH+N5Q== X-UI-Out-Filterresults: notjunk:1;V01:K0:m7uZePxFEJE=:nFnjR11HzagpqAeZpL8PjA MbvN93OnVKg4vAZsaHZgHgq7CxaS+n+1fzG2FVprH1cDlHCaL22t6IvqF+Pf0ovU5P9/X+hw2 ECPBdlju06uv3MtaFGA5vLflCv+KLS1w4/mgGBh3qOttoXJcB9QrnggluU5TFOnYikjr7AXH8 u9l+kWWVYWlfjmA0+GlFlKyKOaXSrNvVUtchO9Axw8jIjBWHtCYiLcabh1skjRgIXlLjHQ2Zr 5VJx/kdFy7ucZceUXKmesd5s4B0/thn7yWutZvaqlX3k0DbTogABVhQ8WXPO5zni0qoYW1AzC 3KvytmGsOX9TuVVuM4ef9ZxL1knKrCz2wCnfQbbX2JWiky4nKHOo7JKmMIGbZP997tjPULu09 lpWWrAQFkbSuDHdop5Yp4uRZPN6FHZiEl5UcEaqevm+nJy4VisLskUjeJwLRd2eXS4oWly/7Z oWXNk0KYIQezIX5QhhrWtyEhtsghlZD0VhN4yEgf6Y80K0F1IfqQdbyu/72dCxMUHugeMW0GX Faklc+31eo+yp8F9hHHsxAz4IbTRmCEIaWFPe0dl9npJsfrOuDHT14XTMbm4oBceZ4Fk4up61 W9oeBBbgOARezy+v9TjffsQY2+VLB+Nfn8BuARwUrGAbtBlSMta7p/ny4v6c61i+WJIbLC6fv APHs5LHXkb+oyMI5ccrQQOk2IE5GdU8rBHdX7olDRfcfLxtOTXzhpVngbGyQ2sJfOf8mD0MAe wFFcfH7IC32E/ft/ANrjlrqfjfG0EpYuBN1FupruJDOAGk2duoRpcKXWKIz3F0fa/RZQOa7pG GNUAL6E Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] Long-RTT broken again X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 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, 03 Nov 2015 08:21:14 -0000 Hi Jonathan, On Nov 3, 2015, at 02:39 , Jonathan Morton = wrote: >=20 >> On 2 Nov, 2015, at 20:29, Sebastian Moeller wrote: >>=20 >> the initial commit was not as well tested as it should have been=85 >=20 > Indeed, and the obvious problems with it were why I reverted it. I = was able to put in a partial implementation by other means at the same = time, but haven=92t yet had time to polish off the rough edges. Well, I believe one of the next steps needs to be to expose = limit to user-space, which would have Toke allowed his measurements and = would have followed the example of most/all other leaf qdiscs and put = policy into user space where it arguably belongs=85 if no one beats me = to it I might go and try implement this, but behold it is not going to = be pretty... >=20 > The question remains why a 15MB buffer (which comfortably exceeds the = traditional FIFO rule of thumb for 1 second * 100Mbps) is apparently = insufficient according to Toke=92s tests, even with the target increased = as requested. That also is a valid question that should be answered, but it = would be great if cake had just enough knobs to allow working around = this issue, to sort of compartmentalize different problem spheres and = allow concurrent progress on different issues, no? Also what about the BUG_ON I managed to trigger during my = testing? Could we just change this to a WARN_ON and =93gracefully=94 = fail the initialization of the qdisc with an appropriate message to the = user? I am not sure that cake=92s unhappiness should wedge a whole = system... Best Regards Sebastian >=20 > - Jonathan Morton >=20