From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-x234.google.com (mail-wr0-x234.google.com [IPv6:2a00:1450:400c:c0c::234]) (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 CFE103CB4B for ; Thu, 19 Apr 2018 17:17:47 -0400 (EDT) Received: by mail-wr0-x234.google.com with SMTP id d1-v6so17622520wrj.13 for ; Thu, 19 Apr 2018 14:17:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=eventide.io; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=lrOdgyejdjWl/lqAyVwEctNRYCEKFjjhrvjSZeXdn6M=; b=OPFM5yTPyBEoYTLLVjTTDbT7AEKWwuGcgeETQ9DlrApRT2wI7cKQGQZwnhClsu8Knl VjnKR2MtqMrxE1DsdmvUCYE0crvLxYOPbPw2qywzA93FVBBNywmis5/Zekn8mzZJQAXw APtyZxv0TEQoqJSsfPQrUT9JR1UixO0jAHjyEqAiIc0lNvXE1TqlYvFfTEAj3y7OkKB9 P4lkRcP/PuaBdW9NHutDAwoncjI9dJQOtWoJAUY4yFO3RKygckx8sCJ9lScN0m9c1Jl8 kgwShej2qjottSeOB2Y3ricPj0c+2AjrrznhE7g1Zl31aANprt74vh7gHJaU/q9aBN5l 7EaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=lrOdgyejdjWl/lqAyVwEctNRYCEKFjjhrvjSZeXdn6M=; b=lVx8XgODuE2qJj81YL7sYUJL36BqF1EB2YdriJbZkaG8Swv83hIy/8A4HbH76Cml3y Rd7g7Gnz0g4l+bgYHFcT/cAO4sFALsjimsyYluxNRiYW8uFVOEuH3s7whGWkGmJXlffB ifvMhOnUdvC5525XpaOUzU33dFITMdM39PMzajAvrLtLv4TJhKscjDMSZiLe2KpAUVx/ 7IhB+B8E1/ydwQPfVP+Tnu+x1ZUCc/E0xX3CdRH/NWoSI01kPqCjt4kOS3XMfm/ZNnCL XDWtpR208OBMAAv25nI39IOY7GthVmYmx8Fr9pYlyIXEWypw521odKqtLquJh3CULrjA B1LA== X-Gm-Message-State: ALQs6tCPH/9fduxTJPdoI8p+PsgkCenaqY1mX+AuOA0B5J5lcsomFIka NUQH+lAvvPtmkbhjdu5kL0THgw== X-Google-Smtp-Source: AIpwx4+BVqmIjouZAZj0hHNd6fayOogx8lmIxg5ugsb07Zq3c5K+Zaw334i8Xe1kQ1puWLeac/utHA== X-Received: by 2002:adf:9dc5:: with SMTP id q5-v6mr5608642wre.74.1524172666996; Thu, 19 Apr 2018 14:17:46 -0700 (PDT) Received: from tron.luk.eventide.io (h-1169.lbcfree.net. [185.193.85.130]) by smtp.gmail.com with ESMTPSA id o101-v6sm6329154wrb.44.2018.04.19.14.17.46 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 19 Apr 2018 14:17:46 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Pete Heist In-Reply-To: <129AF371-272F-4462-9EAF-71C861164E4C@eventide.io> Date: Thu, 19 Apr 2018 23:17:45 +0200 Cc: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Cake List Content-Transfer-Encoding: quoted-printable Message-Id: <6D78919D-C4F0-4EC6-A9D4-BA81EEAC334D@eventide.io> References: <20180416.110000.1863692416063182988.davem@davemloft.net> <87efjf5gne.fsf@toke.dk> <612F0368-751A-4127-B1F4-139FF5C3D315@eventide.io> <0B624E0E-BF6C-4201-B20A-F6B77740B225@gmail.com> <129AF371-272F-4462-9EAF-71C861164E4C@eventide.io> To: Jonathan Morton X-Mailer: Apple Mail (2.3124) Subject: Re: [Cake] net-next is OPEN... 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 21:17:48 -0000 > On Apr 18, 2018, at 7:43 AM, Pete Heist wrote: >=20 > I also think I saw this happen at lower bandwidths as well, when the = CPU wasn=E2=80=99t loaded. What I=E2=80=99ll do is re-test on the = current version I have at, say, 50Mbit (or to where load drops = substantially), then update to the head and test again, and let you = know... >=20 >> On Apr 17, 2018, at 3:52 PM, Jonathan Morton = wrote: >>=20 >>> On 16 Apr, 2018, at 11:55 pm, Pete Heist wrote: >>>=20 >>> I remember that fairness behavior at low RTTs (< 20ms) needed to be = either improved or documented >>=20 >> The reason for the behaviour, IIRC, was that throughput dropped below = 100% when the latency target was reduced too much. Since then there has = been a small change which might improve it a little, so a retest would = be reasonable. At 50mbit I don=E2=80=99t see nearly as much fairness degradation at low = RTTs, although there=E2=80=99s some. Even at 100us, =E2=80=9Cfairness=E2=80= =9D is around 1.1 (1.0 being perfectly fair) instead of the 2.x I saw at = 500mbit. I do not see much of a difference between the latest code = (16d7fed, 2018-04-17) and the previous code I tested (7061401, = 2017-12-01), if that info is of use. RTT: tcp_1up upload Mbps / tcp_12up upload Mbps 7061401 (2017-12-01): 100us: 23.80 / 25.85 1ms: 23.89 / 29.46 10ms: 23.93 / 24.66 40ms: 23.96 / 24.10 100ms: 23.97 / 24.12 16d7fed (2018-04-17): 100us: 23.97 / 26.49 1ms: 23.89 / 26.27 10ms: 23.98 / 26.37 40ms: 23.94 / 24.08 100ms: 23.97 / 24.12 I can post reports / flent files on request. So it appears this is CPU related, and not worth exploring further(?) = and not worth documenting(?) other than that once things have = stabilized, documenting how Cake degrades under various extreme = conditions would be informative. Well, here=E2=80=99s to science and a good walk in the weeds=E2=80=A6