From owner-freebsd-net@FreeBSD.ORG Wed Feb 20 02:37:56 2013 Return-Path: Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 527D1B28; Wed, 20 Feb 2013 02:37:56 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: from mail-we0-x231.google.com (mail-we0-x231.google.com [IPv6:2a00:1450:400c:c03::231]) by mx1.freebsd.org (Postfix) with ESMTP id 941ABA22; Wed, 20 Feb 2013 02:37:55 +0000 (UTC) Received: by mail-we0-f177.google.com with SMTP id d7so6128926wer.36 for ; Tue, 19 Feb 2013 18:37:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=6cVMV/Y4pEAlirTUL55dNS2afqD/JMKXGAeXhLu+RNU=; b=SUwEhSmavm8Rj7bpJ5yRL6k70U7/792QrLTrWFZ/cTCDu5ZDb4lKuSjJC/4agBuWg9 2Owem6CVt0LBPRpEmTATr1skR4C7f3/DsJcVEi7TdyOadRVqqFXq9CF3WTxFx96ErD4C 23bIGKuV5XTqMHXGTMwddRA1R5WZPs4Fy3teyJgmJAqACmdN4K4g4cnr3NZsKPWoYPTf M6derwW08dUckps5gmvUgVpxNoM2A48f6az7SHYzL/e1OaPiYrCqBc8+Izi4iBwAtjwc lvNfwt3fjzg1DuGDY25VzFwDzLQxvJlxgOdLKj+4M562fwDLnSlipxRf8Qd5B5WJRjlM YSFQ== MIME-Version: 1.0 X-Received: by 10.180.105.232 with SMTP id gp8mr30860113wib.33.1361327874600; Tue, 19 Feb 2013 18:37:54 -0800 (PST) Received: by 10.194.163.232 with HTTP; Tue, 19 Feb 2013 18:37:54 -0800 (PST) In-Reply-To: <51242B05.1040003@room52.net> References: <201301221511.02496.jhb@freebsd.org> <511B4DEF.8000500@freebsd.org> <511B6A87.5060000@freebsd.org> <511BA29E.5050501@freebsd.org> <511BA7D9.3050709@freebsd.org> <511C3FB8.40506@freebsd.org> <51242B05.1040003@room52.net> Date: Wed, 20 Feb 2013 10:37:54 +0800 Message-ID: Subject: Re: [PATCH] Add a new TCP_IGNOREIDLE socket option From: Sepherosa Ziehau To: Lawrence Stewart Content-Type: text/plain; charset=ISO-8859-1 Cc: Andre Oppermann , John Baldwin , "freebsd-net@freebsd.org" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Feb 2013 02:37:56 -0000 On Wed, Feb 20, 2013 at 9:46 AM, Lawrence Stewart wrote: > *crickets chirping* > > Time to move this discussion forward... > > > If any robust counter-arguments exist, now is the time for us to hear > them. I haven't read anything thus far which convinces me that we should > not provide knobs to tune our stack's dynamics. > > In the absence of any compelling counter-arguments, I would like to > propose the following: > > - We rename the net.inet.tcp.experimental sysctl node introduced in > r242266 for IW10 support to net.inet.tcp.nonstandard, and re-parent the > initcwnd10 sysctl under this node. > > - We introduce a new net.inet.tcp.nonstandard.allowed sysctl variable > and default it to 0. Only when it is changed to 1 will we allow starkly > non standards compliant behaviour to be enabled in the stack. As a more > complex but expressive alternative, we can make the sysctl take a bit > mask or CSV string which specifies which non-standard options the sys > admin permits (I'd prefer this as we can easily test non-standard > options like IW10 in head without blanket enabling all non standard > behaviour). > > - We introduce a new net.inet.tcp.nonstandard.noidlereset sysctl > variable, and use it to enable/disable window-reset-after-idle behaviour > as proposed by John. > > - We don't introduce a TF_IGNOREIDLE sockopt, and instead introduce a > more generic sockopt and/or mechanism for per-application tuning of all > options which affect stack dynamics (both standard and non-standard > options). I'm open to suggestions on what this could/should look like. Lawrence, A route metric? BTW, as for IW10, it could also become a route metric (as proposed by the draft author's presentation http://www.ietf.org/proceedings/79/slides/tcpm-0.pdf) John, I came across this draft several days ago, you may be interested: http://tools.ietf.org/html/draft-ietf-tcpm-newcwv-00 This one is a bit old, but it is still interesting to read (cited by the above draft): http://tools.ietf.org/html/draft-hughes-restart-00 Best Regards, sephe -- Tomorrow Will Never Die