From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-13-ewr.dyndns.com (mxout-027-ewr.mailhop.org [216.146.33.27]) by lists.bufferbloat.net (Postfix) with ESMTP id 3BAD22E0271 for ; Tue, 15 Mar 2011 17:45:55 -0700 (PDT) Received: from scan-12-ewr.mailhop.org (scan-12-ewr.local [10.0.141.230]) by mail-13-ewr.dyndns.com (Postfix) with ESMTP id 6B985A4BC38 for ; Wed, 16 Mar 2011 00:45:55 +0000 (UTC) X-Spam-Score: 0.0 () X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 70.61.120.58 Received: from smtp.tuxdriver.com (charlotte.tuxdriver.com [70.61.120.58]) by mail-13-ewr.dyndns.com (Postfix) with ESMTP id 1478DA4BC24 for ; Wed, 16 Mar 2011 00:45:55 +0000 (UTC) Received: from uucp by smtp.tuxdriver.com with local-rmail (Exim 4.63) (envelope-from ) id 1Pzes5-0007gG-3X; Tue, 15 Mar 2011 20:45:53 -0400 Received: from linville-8530p.local (linville-8530p.local [127.0.0.1]) by linville-8530p.local (8.14.4/8.14.4) with ESMTP id p2G0WZR7029081; Tue, 15 Mar 2011 20:32:35 -0400 Received: (from linville@localhost) by linville-8530p.local (8.14.4/8.14.4/Submit) id p2G0WYHw029079; Tue, 15 Mar 2011 20:32:34 -0400 Date: Tue, 15 Mar 2011 20:32:34 -0400 From: "John W. Linville" To: Rick Jones Message-ID: <20110316003234.GC28663@tuxdriver.com> References: <4D7F4121.40307@freedesktop.org> <20110315175942.GA10064@goldfish> <1300212877.2087.2155.camel@tardy> <20110315183111.GB2542@tuxdriver.com> <29B06777-CC5F-4802-8727-B04F58CDA9E3@gmail.com> <20110315205146.GF2542@tuxdriver.com> <1300224719.2087.2173.camel@tardy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1300224719.2087.2173.camel@tardy> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] Random idea in reaction to all the discussion of TCP flavours - timestamps? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Mar 2011 00:45:56 -0000 On Tue, Mar 15, 2011 at 02:31:59PM -0700, Rick Jones wrote: > On Tue, 2011-03-15 at 16:51 -0400, John W. Linville wrote: > > On Tue, Mar 15, 2011 at 09:40:06PM +0200, Jonathan Morton wrote: > > > > > > On 15 Mar, 2011, at 8:31 pm, John W. Linville wrote: > > > > > > > If you don't throttle _both_ > > > > the _enqueue_ and the _dequeue_, then you could be keeping a nice, > > > > near-empty tx queue on the host and still have a long, bloated queue > > > > building at the device. > > > > > > Don't devices at least let you query how full their queue is? > > > > I suppose it depends on what you mean? Presumably drivers know that, > > or at least can figure it out. The accuracy of that might depend on > > the exact mechanism, how often the tx rings are replinished, etc. > > > > However, I'm not aware of any API that would let something in the > > stack (e.g. a qdisc) query the device driver for the current device > > queue depth. At least, I don't think Linux has one -- do other > > kernels/stacks provide that? > > HP-UX's lanadmin (and I presume the nwmgr command in 11.31) command will > display the "classic" interface MIB stats, which includes the outbound > queue length. What it does (or should do) for that statistic in the > face of a multi-queue device I've no idea :) But that is capacity, right? Not current occupancy? I thought that was the outcome of an earlier thread? John -- John W. Linville Someday the world will need a hero, and you linville@tuxdriver.com might be all we have. Be ready.