From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2.tohojo.dk (mail2.tohojo.dk [77.235.48.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id C1BEB21F440 for ; Tue, 3 Nov 2015 03:50:41 -0800 (PST) X-Virus-Scanned: amavisd-new at mail2.tohojo.dk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=201310; t=1446551439; bh=PcP0SN2pXEPcL5khZwb1RGbfMUAwXDjJq3RinBpznsk=; h=From:To:Cc:Subject:References:Date:In-Reply-To; b=kMNHcIn00Ep5JxRYgeyvVnbnjcYulLFamCQDYnRf9L0828PEJLO6aNXyVrv6hsr1X +Ye0J5WZ2Jj1vC7dwjJOaJZx7PhLVdAX8Wte6dCE9JDZtLkwmiELc9apV4he4GTMLc wzs1TM3eLM54mf9aGE1wL/GG2gvFHA6ffMdiV0LA= Received: by alrua-kau.kau.toke.dk (Postfix, from userid 1000) id AE63DC402A1; Tue, 3 Nov 2015 12:50:38 +0100 (CET) From: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= To: Jonathan Morton References: <87pozspckj.fsf@toke.dk> <6A2609D9-7747-487B-9484-ECC69C50DE96@gmx.de> Date: Tue, 03 Nov 2015 12:50:38 +0100 In-Reply-To: (Jonathan Morton's message of "Tue, 3 Nov 2015 03:39:06 +0200") X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <874mh3pai9.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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 11:51:04 -0000 Jonathan Morton writes: >> On 2 Nov, 2015, at 20:29, Sebastian Moeller wrote: >>=20 >> the initial commit was not as well tested as it should have been=E2=80=A6 > > 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=E2=80=99t yet had time to polish off the rough edges. Well I would have preferred that you kept the part that fixed the (real, demonstrated) bug, and then went back and fixed the (theoretical) memory limit issues later; which I was well aware were there. And BTW, I'm not entirely convinced that this is anything but a theoretical problem; I challenge anyone to actually demonstrate a router crashing from OOM from this. :) > 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=E2=80=99s tests, even with the target incr= eased > as requested. Because it's not a 15MB buffer; it's a 10240 packet buffer. So anything from ~.5 to ~15MB. In this case, it's a bidirectional test, so about half the packets will be tiny ACKs. I guess doing byte accounting would actually be better here, regardless of what happens to the overall limit...= :) -Toke