From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e7.ny.us.ibm.com (e7.ny.us.ibm.com [32.97.182.137]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e7.ny.us.ibm.com", Issuer "GeoTrust SSL CA" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 1C92921F1B8 for ; Mon, 3 Dec 2012 07:03:47 -0800 (PST) Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 3 Dec 2012 10:03:45 -0500 Received: from d01dlp03.pok.ibm.com (9.56.250.168) by e7.ny.us.ibm.com (192.168.1.107) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 3 Dec 2012 10:03:44 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id C24A9C9006A; Mon, 3 Dec 2012 10:03:42 -0500 (EST) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qB3F3eVf246712; Mon, 3 Dec 2012 10:03:41 -0500 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qB3F3cJH020345; Mon, 3 Dec 2012 08:03:40 -0700 Received: from paulmck-ThinkPad-W500 ([9.47.24.61]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id qB3F3aQZ019662; Mon, 3 Dec 2012 08:03:36 -0700 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id 55E82EBF62; Mon, 3 Dec 2012 07:03:31 -0800 (PST) Date: Mon, 3 Dec 2012 07:03:31 -0800 From: "Paul E. McKenney" To: Dave Taht Message-ID: <20121203150331.GI2605@linux.vnet.ibm.com> References: <20121123221842.GD2829@linux.vnet.ibm.com> <20121128172058.GB2474@linux.vnet.ibm.com> <20121202230635.GA16359@linux.vnet.ibm.com> <87obib5qf8.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12120315-5806-0000-0000-00001C7BD4FD Cc: Paolo Valente , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Eric Raymond , "codel@lists.bufferbloat.net" , "cerowrt-devel@lists.bufferbloat.net" , bloat , David Woodhouse , John Crispin Subject: Re: [Cerowrt-devel] FQ_Codel lwn draft article review X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list Reply-To: paulmck@linux.vnet.ibm.com List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 Dec 2012 15:03:49 -0000 On Mon, Dec 03, 2012 at 12:31:30PM +0100, Dave Taht wrote: > On Mon, Dec 3, 2012 at 12:24 PM, Toke Høiland-Jørgensen wrote: > > "Paul E. McKenney" writes: > > > >> And please see attached. Thoughts? > > > >"In addition, you network driver must be instrumented to support packet > ^^^^ your ethernet network driver Good catch, fixed! Thanx, Paul > different technologies have different answers. BQL is an answer to > ethernet. ADSL benefits from closely tieing buffering to being nearly > zero and to signalling the actual packet delivery from the hardware. > > Wifi, well, I don't want to talk about wifi... > > > scheduling..." > > > > So what happens if you run fq_codel on a non-BQL driver? > > you have no control. The tx queue rings are flooded before control is > handed back to the fq_codel scheduler. You can get some control back > on a non-BQL driver by reducing the number of tx descriptors > dramatically, but that leads to issues with small vs big packets.... > > Be worthwhile to plot BQL vs non-BQL on the same driver/device.... > > > > > -Toke > > > > -- > > Toke Høiland-Jørgensen > > toke@toke.dk > > > > -- > Dave Täht > > Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html >