From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 75F8921F0BA for ; Mon, 25 Jun 2012 07:54:56 -0700 (PDT) Received: by wibhm2 with SMTP id hm2so106639wib.4 for ; Mon, 25 Jun 2012 07:54:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=8XTOKo8l3wgF0t0VmORhAIfoK9ICr4C/3YtXFWsEd1U=; b=H02zvUlJSxyl8tYDtjdjMAdw4SFu0cUEIttQncNDT6yapnXgzzcuCcOwxCWfE0NkIF 6J+K/asOqHk26DX2T7GlEv62DTNlhieVJ9pF/JpxXa58ImZTPRtNNlW54Njnw23x26Gt /7EYRoNYVMCBQbZbL+ShDR0palmj3DLFU38z4vf6LBz/iWuI5eOLv/+mqWRLJg6hmn8Q EAYnwm3FcreeC3y/xS78LI/Z36JGuhfBeI5O4KhIxiYvrHVxeWjGfZxXL657XXZwyrOj r3DGY/NtgCMpIE/h51//kwFwNC4zTRfodugyVUdMZId707N7WdLQFeFw8LRqszNOXPwc CZXA== MIME-Version: 1.0 Received: by 10.216.202.22 with SMTP id c22mr6129320weo.10.1340636093596; Mon, 25 Jun 2012 07:54:53 -0700 (PDT) Received: by 10.223.103.199 with HTTP; Mon, 25 Jun 2012 07:54:53 -0700 (PDT) In-Reply-To: <1340602168.23933.22.camel@edumazet-glaptop> References: <1340600422-1806-1-git-send-email-dave.taht@bufferbloat.net> <1340602168.23933.22.camel@edumazet-glaptop> Date: Mon, 25 Jun 2012 07:54:53 -0700 Message-ID: From: Dave Taht To: Eric Dumazet Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: codel@lists.bufferbloat.net, =?ISO-8859-1?Q?Dave_T=E4ht?= Subject: Re: [Codel] [RFCv2 PATCH] iproute2: Add ecn_target option to codel and fq_codel X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jun 2012 14:54:57 -0000 On Sun, Jun 24, 2012 at 10:29 PM, Eric Dumazet wro= te: > On Sun, 2012-06-24 at 22:00 -0700, Dave T=E4ht wrote: >> From: Dave Taht >> >> ECN was not part of the original codel design and adding support >> for it revealed problems in two areas. 1) ECN can be gamed. >> 2) Dropping packets under overload more rapidly frees up >> bandwidth than marking packets. >> >> Two possible scenarios of use - on egress from a network, >> ecn_target could be set low, to drop more often, to >> ensure lowest latency for other packets. >> >> On ingress, it could be set high to mark packets more often, >> to lower data loss while still signalling the end application >> that bandwidth is a problem. >> >> ecn_target is not engaged until after codel enters a dropping >> state overall. > > I would suggest 'drop_above' instead of ecn_target, since its quite > different than the 'target' OK. I will respin this after resolving the issue I raised in the previous p= atch comment (just switch ecn to being an int?), and do some testing. As noted I was (de)impressed at the amount of ecn drops I had with it set to 2*targe= t on pure ecn enabled streams. In one test it was 95% drops... And I'm still open to saner approaches. Another one might be to at graduate= d levels drop big packets down to smaller ones. > (And dont display/output it if ecn is not set, no need to confuse users > who didn't enable ecn on CoDel) > > > > _______________________________________________ > Codel mailing list > Codel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel --=20 Dave T=E4ht http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-6 is out with fq_codel!"