From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) (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 2EE063CB37 for ; Mon, 5 Aug 2019 15:10:44 -0400 (EDT) Received: by mail-lf1-x131.google.com with SMTP id x3so58996090lfc.0 for ; Mon, 05 Aug 2019 12:10:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=W0tlL119i+TcTvh+AchxgsunjTIOgzMgwlHu2fdP9b8=; b=UG0iovpPJFaCKC3Bf2sDRef8hq4YnCMVZNSeU+H8Sa8aBnTkBljCFLV0A5O8DdDAsa 9gb95SfYWyvl2YU57vQZNyCsmHzkHubnzXs6uIoUabMcFJWbFp+sK6x+/el5ahOlYAVR YvI/1aHG6+olbTWJf5zrfQOIeoU9ESeKvzW5cWqWTP0ClTkxh0Nfldm2vR+3fViU00Ab UBXmTPh6cOvxx7PUFXis7Qp/LxzKC2O4i9sURnV5i7Dsq6ILB+fY6hTz7miRjO5/+u3E lGnj+45xscYobE3t5zjvwqLMAQoYbI1gFXYT4G2vfKSOPA2LXF77uS+IVeuBEEuCwkUW r2yw== 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=W0tlL119i+TcTvh+AchxgsunjTIOgzMgwlHu2fdP9b8=; b=CRWHTaF+bZhtMGblBLLJ+lOmBTkLlOc2JiETSK6yP+hBJGiYG2LEz+3h0VsuleuCR1 kwzAXM16D6R5vIlxNVXnvFHezTwjFRh3f/e5YbGlPRaD4b6VKNSIkpbBEHr4G1Opy+VB 6G+kbr0ae4UBqa1Nu6r3y04OAoO2Ww4RR0k5b9bDxca3LLCL25oHp9p/obEgBZmRz4Bx ROnzu6Nx/t2nmxU9AbWF7Lm78Q4odBPH3UMjMgDMABnWOxIcp9QH63gQFLuHx45q8k9Q vzR4zKgYGMfsKlvdkvoWM+k1qSi/ZOAwaUmozJqayd4raC7ZVxlmhrpAApJy1S723nC0 RgzQ== X-Gm-Message-State: APjAAAXVrr/hUdT8F0MHAQU18N4Q+PkL1HtfrhDHMJuUCySQn2Cfgt1c jyDtUCSVxRcUdehP0fLYa/M= X-Google-Smtp-Source: APXvYqxGrR/BBokjtSr38KpNN6DtVG3GmYDL4vx75kd1rr5mKLYHHPzNARqE4i2aCRO/kgAnnG3bWQ== X-Received: by 2002:a19:8c57:: with SMTP id i23mr6567650lfj.192.1565032243174; Mon, 05 Aug 2019 12:10:43 -0700 (PDT) Received: from jonathartonsmbp.lan (83-245-237-193-nat-p.elisa-mobile.fi. [83.245.237.193]) by smtp.gmail.com with ESMTPSA id w8sm2136422lfq.53.2019.08.05.12.10.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Aug 2019 12:10:42 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Jonathan Morton In-Reply-To: Date: Mon, 5 Aug 2019 22:10:40 +0300 Cc: ECN-Sane Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Dave Taht X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Ecn-sane] net-next dctcp mod question X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Aug 2019 19:10:44 -0000 > On 5 Aug, 2019, at 9:21 pm, Dave Taht wrote: >=20 > The SCE tree had two key looking modifications to it that seem to have > been superceded by net-next. >=20 > My reading of the remaining differences seem to be resolved in the > state machine where setting the last portion > of the SCE patch appears to do a decrease on multiple losses. ? Can I > not forward port these? I basically gave up on the original DCTCP code, and re-implemented it = nearly from scratch for DCTCP-SCE. In the process I deleted a lot of = unnecessary complications which actually slowed the response by about 1 = RTT, and fixed the various bugs which stopped it from responding = correctly to loss and RFC-3168 CE marks (though the latter was by design = in the original). I noticed that work had been done on the original when I tried to apply = the SCE changes as a patch over the Raspberry Pi tree. Everything = applied cleanly besides that. I just deleted that part of the patch and = moved on without investigating more deeply. Usefully, you can simulate how DCTCP is supposed to work by mangling CE = marks into SCE ones at the receiver (SCE enabled), running DCTCP-SCE at = the sender, and inserting your choice of CE marking scheme in the = middle. We did that in Montreal to substantiate our calculation of how = TCP Prague would react to Codel if it worked as designed. - Jonathan Morton