From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e9.ny.us.ibm.com (e9.ny.us.ibm.com [32.97.182.139]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e9.ny.us.ibm.com", Issuer "GeoTrust SSL CA" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id E826D208AAD for ; Mon, 3 Dec 2012 07:08:04 -0800 (PST) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 3 Dec 2012 10:08:01 -0500 Received: from d01dlp03.pok.ibm.com (9.56.250.168) by e9.ny.us.ibm.com (192.168.1.109) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 3 Dec 2012 10:07:56 -0500 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id 5A5CFC9001C; Mon, 3 Dec 2012 10:07:55 -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 qB3F7s0R276694; Mon, 3 Dec 2012 10:07:54 -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 qB3F7dcD009969; Mon, 3 Dec 2012 08:07:40 -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 qB3F7cpi009761; Mon, 3 Dec 2012 08:07:38 -0700 Received: by paulmck-ThinkPad-W500 (Postfix, from userid 1000) id C6116EBF5B; Mon, 3 Dec 2012 06:58:49 -0800 (PST) Date: Mon, 3 Dec 2012 06:58:49 -0800 From: "Paul E. McKenney" To: Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= Message-ID: <20121203145849.GH2605@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> <87fw3n5m9g.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: <87fw3n5m9g.fsf@toke.dk> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12120315-7182-0000-0000-0000037A8F20 Cc: Paolo Valente , 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 15:08:05 -0000 On Mon, Dec 03, 2012 at 01:54:35PM +0100, Toke Høiland-Jørgensen wrote: > Dave Taht writes: > > > 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.... > > Right, so BQL is pretty much a requirement to get anything worthwhile > out of fq_codel? Or is that too strongly put? If I understand the code correctly, without BQL, FQ-CoDel does not get invoked at all. Thanx, Paul > Without BQL, exactly how much does the driver queue up? I've heard > someone say 1000 packets for ethernet, but is that in a different > context? E.g. pfifo_fast uses /sys/class/net/*/tx_queue_len for queue > length (I think?), but if the qdisc doesn't, does the driver? > > -Toke > > -- > Toke Høiland-Jørgensen > toke@toke.dk