Date: Wed, 3 Nov 2004 10:57:49 +0100 From: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl> To: freebsd-ipfw@freebsd.org Subject: Re: [PATCH] burstable dummynet pipe Message-ID: <20041103095749.GA56028@shellma.zin.lublin.pl> In-Reply-To: <20041102223835.B42486@xorpc.icir.org> References: <20041031203558.GA49557@shellma.zin.lublin.pl> <20041102223835.B42486@xorpc.icir.org>
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On Tue, Nov 02, 2004 at 10:38:35PM -0800, Luigi Rizzo wrote: Helo, > > Configuring `x bytes burst' means we are allowing to transmit x bytes > > with increased (by default: ~2x) speed. After that, traffic passes > > through pipe as usual (bw-limited), however, burst credit is slowly > > (by default: ~10x lower than bw) accumulated when pipe is idle (low > > to tell the truth, the 2x and 10x thing seems to me a rather > kludgy and arbitrary way to implement 'bursts'. > The most straightforward way to implement this feature is > to let the pipe be "burst" bytes ahead of the programmed rate, > which results in a rather trivial change to the current code. > If you really want to burst out data and recover credt at a > different rate, these extra rates should be configurable. Fully agree, these values are hardcoded because this is a concept preview, and as I wrote, this is a poor patch. It also won't work for pipes connected with WFQ queues (but I'm not too sure if it is worth implementing). > so if someone thinks of committing this patch in the current form, > please at least note in the commit log that i am opposed to that. Commiting it like this is a bad idea. I've posted this here only to see if someone is interested and maybe can pick it up. Since I do not even know C language, I'm not a proper person to implement this. I've made this patchset having two things in mind: . small burst may be a good thing for web users, they just: click, <reading webpage>, click, <reading webpage>, ... so we can allow them to exceed their bw for few seconds, just to load typical webpage. . bigger burst may be a good thing when limiting per-user upstream usage on assymetric lines, e.g. on 128kbit/512kbit ADSL limit user so one is able to send 64kbit/s up, however, after sending more than x MBytes (e-mail with attachment) his speed will go down to 32kbit/s. regards, -- Paweł Małachowski
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