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[83.245.234.255]) by smtp.gmail.com with ESMTPSA id n10sm509963ljj.16.2018.04.19.01.11.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Apr 2018 01:11:35 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) From: Jonathan Morton In-Reply-To: Date: Thu, 19 Apr 2018 11:11:33 +0300 Cc: Dave Taht , Cake List Content-Transfer-Encoding: quoted-printable Message-Id: References: <87vacq419h.fsf@toke.dk> <874lk9533l.fsf@toke.dk> <87604o3get.fsf@toke.dk> <578552B2-5127-451A-AFE8-93AE9BB07368@gmail.com> <87r2nc1taq.fsf@toke.dk> <0BB8B1FD-6A00-49D6-806E-794BD53A449F@gmx.de> <3457DD8E-0292-4802-BD1E-B37771DCADA2@gmail.com> <87fu3s1om2.fsf@toke.dk> To: Luca Muscariello X-Mailer: Apple Mail (2.3445.6.18) Subject: Re: [Cake] A few puzzling Cake results 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: Thu, 19 Apr 2018 08:11:37 -0000 > This is why I think that any fix that tries to solve this problem in = the queueing system should be avoided. It does not solve the real = problem (overload) and introduces latency. Most people, myself included, prefer systems that degrade gracefully = instead of simply failing or rejecting new loads. Systems that exhibit = the latter behaviours tend to be open to DoS attacks, which are = obviously bad. Or users obsessively retry the failed requests until = they succeed, increasing total load for the same goodput and inferior = perceived QoS. Or ignorant application developers try to work around a = perceived-unreliable system by spamming it with connections so that = *their* traffic ends up getting through somehow. By designing a system which exhibits engineering elegance where = practical, and graceful degradation otherwise, I try to encourage others = to do the Right Thing by providing suitable incentives in the system's = behaviour. The conventional way (of just throwing up one's hands when = load exceeds capacity) has already been tried, extensively, and = obviously doesn't work. Cake does better. Since Pacific islands are topical, perhaps look up the story of the = California Clipper, which had to trek from NZ to NY "the long way round" = after Japan entered the war. To do so, the crew had to push the = aircraft's endurance beyond the normal limits several times, and run it = on the 90-octane fuel that was available in India and Africa, rather = than the 100-octane fuel that the engines had been designed for. = Eventually part of the exhaust fell off one engine, and they had no = spare - but the engine kept working, so they just posted a lookout to = account for the increased fire hazard, and kept on flying. They could = do that because it was a well-designed aircraft that had some tolerance = for hard running, and comparatively graceful failure modes (as you'd = hope an airliner would). - Jonathan Morton