From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ia0-f171.google.com (mail-ia0-f171.google.com [209.85.210.171]) (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 173E721F17B; Mon, 26 Nov 2012 13:19:13 -0800 (PST) Received: by mail-ia0-f171.google.com with SMTP id b35so7434805iac.16 for ; Mon, 26 Nov 2012 13:19:12 -0800 (PST) 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=F1CIyXm7JwleYZIdGNiBwnnBcMYzHY8DdSmmI7buF50=; b=zX8yrMaUzNZKNpAOGFtinLcqFRytgJ+dC0EyuYBfFURzHpZ6H9lGPTYQmIfUWRlr3Z rUHBQTo1Anc8s8pWZGFZRqgpZ45zQ0ZTMApb+QUMVFSvXnkNBP6wEN/0fAY0kh4LryWk rQ1eNwrZL/ufShzZ3+QKUVTseEvk2cKP6D92BfjsL1D43Qn2UN3yoPrkgX0qeEXBQqdt hYGeozqMeUjcyQnjw1QPooSMOZ+11sl4vGOhOxlRhhWUDapBJCapJN3/1XCNkqmdGgzL +r2OjEZjoR6yFF9dDuMoCQ3MiIx6sMspUEo4NDNc4mKrz8IItZxt5UrQPQmVV4ICdspZ b5LQ== MIME-Version: 1.0 Received: by 10.50.150.144 with SMTP id ui16mr13420504igb.68.1353964752469; Mon, 26 Nov 2012 13:19:12 -0800 (PST) Received: by 10.64.135.39 with HTTP; Mon, 26 Nov 2012 13:19:12 -0800 (PST) In-Reply-To: <50B3DB92.5070806@hp.com> References: <20121123221842.GD2829@linux.vnet.ibm.com> <87a9u7amon.fsf@toke.dk> <50B3DB92.5070806@hp.com> Date: Mon, 26 Nov 2012 22:19:12 +0100 Message-ID: From: Dave Taht To: Rick Jones Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Paolo Valente , =?ISO-8859-1?Q?Toke_H=F8iland=2DJ=F8rgensen?= , Eric Raymond , codel@lists.bufferbloat.net, cerowrt-devel@lists.bufferbloat.net, bloat , paulmck@linux.vnet.ibm.com, John Crispin Subject: Re: [Codel] FQ_Codel lwn draft article review 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, 26 Nov 2012 21:19:13 -0000 On Mon, Nov 26, 2012 at 10:13 PM, Rick Jones wrote: > On 11/24/2012 08:19 AM, Dave Taht wrote: >> >> On Sat, Nov 24, 2012 at 1:07 AM, Toke H=F8iland-J=F8rgensen >> wrote: >>> >>> "Paul E. McKenney" writes: >>> The UDP ping tests tend to not work so well on a loaded link, >>> however, since netperf stops sending packets after detecting >>> (excessive(?)) loss. Which is why you see only see the UDP ping times o= n >>> the first part of the graph. >> >> >> Netperf stops UDP_STREAM exchanges after the first lost udp packet. > > > The UDP_STREAM test will keep blasting along until the end-of-test timer > fires. It is the non-burst-mode UDP_RR test which comes to a halt on the > first lost datagram. > > >> After staring at the tons of data collected over the past year, on >> wifi, I'm willing to strongly suggest we just drop TCP packets after >> 500ms in the wifi stack, period, as that exceeds the round trip >> timeout... > > > How does WiFi "know" what the TCP RTO for a given flow happens to be? The= re > is no 500 millisecond ceiling on the TCP RTO. the lightspeed equivalent of 1 and half times around the planet is enough time to spend inside of one computer. As for the RTO, you're right... sorta. http://tools.ietf.org/html/rfc6298 But I cannot see any harm in wifi, in simply dropping > 500ms old packets, in the general case, and a lot of potential good. > > rick jones --=20 Dave T=E4ht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.= html